Why is there a wide pupil after lasik? Laser vision correction LASIK. What absolutely should not be done with anisocoria

LASIK surgery is the most widely advertised and widely performed vision correction for astigmatism and other diseases. Millions of surgeries are performed every year around the world.

Much has been said about its benefits, but the possible complications are not often covered. After LASIK, complications of one kind or another of varying severity are observed in approximately 5% of cases. Serious consequences that significantly reduce visual acuity occur in less than 1% of cases. Most of them can only be eliminated through additional treatment or surgery.

The operation is performed using an excimer laser. It allows you to correct astigmatism up to 3 diopters (myopic, hyperopic or mixed). It can also be used to correct myopia up to 15 diopters and farsightedness up to 4 diopters.

The surgeon uses a microkeratome tool to cut the top of the cornea. This is the so-called flap. One end remains attached to the cornea. The flap is turned to the side and access to the middle layer of the cornea is opened.

The laser then evaporates a microscopic portion of the tissue in this layer. This is how a new, more regular shape of the cornea is formed so that light rays are focused precisely on the retina. This improves the patient's vision.

The procedure is fully computer controlled, fast and painless. Once completed, the flap is returned to its place. In a few minutes it adheres firmly and no stitches are required.

Consequences of LASIK

The most common (about 5% of cases) are the consequences of LASIK, which complicate or lengthen the recovery period, but do not significantly affect vision. They can be called side effects. They are usually part of the normal post-operative recovery process.

As a rule, they are temporary and are observed for 6-12 months after surgery while the corneal flap is healing. However, in some cases they can become a permanent occurrence and create some discomfort.

Side effects that do not cause a decrease in visual acuity include:

Deterioration of night vision. One of the consequences of LASIK may be deterioration of vision in low light conditions, such as dim light, rain, snow, fog. This deterioration may become permanent, and patients with dilated pupils are at greater risk of this effect.

Moderate pain, discomfort, and a feeling of a foreign object in the eye may be felt for several days after surgery.

Watery eyes usually occur within the first 72 hours after surgery.

The occurrence of dry eye syndrome is an eye irritation associated with drying of the corneal surface after LASIK. This symptom is temporary, often more severe in patients who have suffered from it before surgery, but in some cases it can become permanent. Requires regular moistening of the cornea with artificial tear drops.

Blurred or double images are most often observed within 72 hours after surgery, but can also occur in the late postoperative period.

Glare and increased sensitivity to bright light are most noticeable in the first 48 hours after correction, although increased sensitivity to light may persist for a long time. The eyes may become more sensitive to bright light than they were before surgery. Driving at night may be difficult.

Ingrowth of the epithelium under the corneal flap is usually noted in the first few weeks after correction and occurs as a result of a loose fit of the flap. In most cases, ingrowth of epithelial cells does not progress and does not cause discomfort or visual impairment for the patient.

In rare cases (1-2% of all LASIK procedures), epithelial ingrowth can progress and lead to flap elevation, which negatively affects vision. The complication is eliminated by performing an additional operation, during which overgrown epithelial cells are removed.

Ptosis or drooping of the upper eyelid is a rare complication after LASIK and usually goes away on its own within a few months after surgery.

It must be remembered that LASIK is an irreversible procedure that has its own contraindications. It involves changing the shape of the cornea of ​​the eye, and after it is performed, it is impossible to return vision to its original state.

If the correction results in complications or dissatisfaction with the result, the patient's ability to improve vision is limited. In some cases, repeated laser correction or other operations will be required.

Complications of laser vision correction using LASIK technology. Analysis of 12,500 transactions

Refractive lamellar corneal surgery dates back to the late 1940s with the work of Dr. Jose I. Barraquer, who first recognized that the optical power of the eye could be altered by removing or adding corneal tissue1. The term "keratomileusis" comes from two Greek words "keras" - cornea and "smileusis" - to cut. The surgical technique itself, instruments and devices for these operations have undergone significant evolution since those years. From the manual technique of excision of part of the cornea to the use of freezing of the corneal disc with its subsequent treatment for myopic keratomileusis (MCM)2.

Then the transition to techniques that do not require tissue freezing, and therefore reduce the risk of opacities and the formation of irregular astigmatism, providing a faster and more comfortable recovery period for the patient 3,4,5. A huge contribution to the development of lamellar keratoplasty, understanding of its histological, physiological, optical and other mechanisms was made by the work of Professor V.V. Belyaev. and his schools6. Dr. Luis Ruiz proposed in situ keratomileusis, first using a manual keratome, and in the 1980s an automated microkeratome - Automated Lamellar Keratomileusis (ALK).

The first clinical results of ALK showed the advantages of this operation: simplicity, rapid restoration of vision, stability of results and effectiveness in the correction of high myopes. However, the disadvantages included the relatively high percentage of irregular astigmatism (2%) and the predictability of results within 2 diopters7. Trokel et al8 proposed photorefractive keratectomy in 1983(25). However, it quickly became clear that with high degrees of myopia, the risk of central opacities, regression of the refractive effect of the operation significantly increases, and the predictability of results decreases. Pallikaris I. et al. 10, combining these two methods into one and using (according to the authors themselves) the idea of ​​Pureskin N. (1966) 9, cutting out a corneal pocket on a pedicle, proposed an operation that they called LASIK - Laser in situ keratomileusis. In 1992 Buratto L. 11 and in 1994 Medvedev I.B. 12 published their variants of the surgical technique. Since 1997, LASIK has gained more and more attention, both from refractive surgeons and from patients themselves.

The number of operations performed each year already amounts to millions. However, with the increase in the number of operations and surgeons performing these operations, with the expansion of indications, the number of works devoted to complications increases. In this article, we wanted to analyze the structure and frequency of complications of LASIK surgery based on 12,500 operations performed in Excimer clinics in the cities of Moscow, St. Petersburg, Novosibirsk and Kiev for the period from July 1998 to March 2000. Regarding myopia and myopic astigmatism, there were 9600 operations (76.8%) were performed for hypermetropia, hypermetropic astigmatism and mixed astigmatism - 800 (6.4%), corrections of ammetropia in previously operated eyes (after Radial keratotomy, PRK, Through corneal transplantation, Thermokeratocoagulation, Keratomileusis, pseudophakia and some others) - 2100 (16.8%).

All operations under consideration were performed on a NIDEK EC 5000 excimer laser, optical zone - 5.5-6.5 mm, transition zone - 7.0-7.5 mm, and multi-zone ablation at high levels. Three types of microkeratomes were used: 1) Moria LSK-Evolution 2 - keratome head 130/150 microns, vacuum rings from - 1 to + 2, manual horizontal cut (72% of all operations), mechanical rotational cut (23.6%) 2 ) Hansatom Baush&Lomb - 500 operations (4%) 3) Nidek MK 2000 - 50 operations (0.4%). As a rule, all LASIK operations (more than 90%) were performed simultaneously bilaterally. Topical anesthesia, postoperative treatment - local antibiotic, steroid for 4 - 7 days, artificial tear according to indications.

Refractive results correspond to world literature data and depend on the initial degree of myopia and astigmatism. George O. Warning III proposes to evaluate the results of refractive surgery according to four parameters: effectiveness, predictability, stability and safety 13. Efficiency refers to the ratio of postoperative uncorrected visual acuity to preoperative best-corrected visual acuity. For example, if postoperative visual acuity without correction is 0.9, and before surgery with maximum correction the patient saw 1.2, then the effectiveness is 0.9/1.2 = 0.75. And vice versa, if before the operation the maximum vision was 0.6, and after the operation the patient sees 0.7, then the effectiveness is 0.7/0.6 ​​= 1.17. Predictability is the ratio of the planned refraction to the received one.

Safety is the ratio of maximum visual acuity after surgery to this indicator before surgery, i.e. A safe operation is when before and after surgery the maximum visual acuity is 1.0 (1/1=1). If this coefficient decreases, then the risk of the operation increases. Stability determines the change in refractive outcome over time.

In our study, the largest group was patients with myopia and myopic astigmatism. Myopia from - 0.75 to - 18.0 D, average: - 7.71 D. Observation period from 3 months. up to 24 months Maximum visual acuity before surgery was more than 0.5 in 97.3%. Astigmatism from - 0.5 to - 6.0 D, average - 2.2 D. Average postoperative refraction - 0.87 D (from -3.5 to + 2.0), patients after 40 years were planned to have residual myopia. Predictability (* 1 D, from the planned refraction) - 92.7%. Average Astigmatism 0.5 D (from 0 to 3.5 D). Uncorrected visual acuity was 0.5 or higher in 89.6% of patients, 1.0 or higher in 78.9% of patients. Loss of 1 or more lines of maximum visual acuity - 9.79%. The results are presented in Table 1.

Table 1. Results of LASIK surgery in patients with myopia and myopic astigmatism with a follow-up period of 3 months. or more (out of 9600 cases, it was possible to trace the results in 9400, i.e. in 97.9%)

Complications after laser vision correction using LASIK

Floor: not specified

Age: not specified

Chronic diseases: not specified

Hello! Please tell me what complications can occur after laser vision correction using the LASIK method?

They say that the consequences can be not only immediately after the operation, but also long-term, several years later. Which?

Tags: laser vision correction, CVS, laser correction, lasik vision correction, lasik method, lasik, corneal erosion, diffuse lamellar kerati, rubbing the eye after correction, eye erosion after surgery, rubbing the eye after lasik

Possible complications after laser vision correction

Keratoconus is a protrusion of the cornea in the form of a cone, formed as a result of thinning of the cornea and intraocular pressure.

Iatrogenic keratectasia develops gradually. Over time, corneal tissue softens and weakens, vision deteriorates, and the cornea becomes deformed. In severe cases, a donor cornea transplant is performed.

Insufficient vision correction (hypocorrection). In the case of residual myopia, when a person reaches the age of 40-45 years, this deficiency is corrected by developing presbyopia. If, as a result of the operation, the resulting quality of vision does not satisfy the patient, repeated correction is possible using the same method or using additional techniques. More often, hypocorrection occurs in people with a high degree of myopia or farsightedness.

Overcorrection is excessively enhanced vision. The phenomenon is quite rare and often goes away on its own in about a month. Sometimes wearing weak glasses is required. But with significant values ​​of hypercorrection, additional laser exposure is required.

Induced astigmatism sometimes appears in patients after LASIK surgery and is eliminated by laser treatment.

“Dry eye” syndrome - dryness in the eyes, a feeling of the presence of a foreign body in the eye, sticking of the eyelid to the eyeball. The tear does not properly wet the sclera and flows out of the eye. “Yugo eye syndrome” is the most common complication after LASIK. It usually goes away 1-2 weeks after surgery, thanks to special drops. If the symptoms do not go away for a long time, it is possible to eliminate this defect by closing the tear ducts with plugs so that the tears linger in the eye and wash it well.

Hayes occurs mainly after the PRK procedure. Clouding of the cornea is the result of a reaction of healing cells. They produce a secret. which affects the transparency of the cornea. Drops are used to eliminate the defect. sometimes laser intervention.

Corneal erosions can form due to accidental scratches during surgery. If postoperative procedures are carried out correctly, they heal quickly.

Deterioration of night vision occurs more often in patients with too wide pupils. Bright sudden flashes of light, the appearance of halos around objects, and illumination of objects of vision occur when the pupil dilates to an area larger than the laser exposure area. They interfere with driving a car at night. These phenomena can be smoothed out by wearing glasses with small diopters and instilling drops that narrow the pupils.

Complications during the formation and restoration of the valve may arise due to the fault of the surgeon. The valve may turn out thin, uneven, short, or cut off to the end (this happens extremely rarely). If folds form on the flap, it is possible to reorient the flap immediately after surgery or subsequent laser resurfacing. Unfortunately, people who have undergone surgery remain forever in the danger zone of trauma. Under extreme mechanical stress, flap detachment is possible. If the flap disappears completely, it cannot be reattached. Therefore, it is necessary to strictly observe the rules of postoperative behavior.

Epithelial ingrowth. Sometimes fusion of epithelial cells from the surface layer of the cornea with the cells located under the flap occurs. When the phenomenon is pronounced, such cells are removed surgically.

"Sahara syndrome" or diffuse lamellar keratitis. When foreign microparticles get under the valve, inflammation occurs there. The image before your eyes becomes blurry. Corticosteroid drops are prescribed for treatment. If such a complication is quickly identified, the doctor washes the operated surface after lifting the valve.

Regression. When correcting large degrees of myopia and hypermetropia, it is possible to quickly return the patient's vision to the level that he had before the operation. If the cornea maintains its proper thickness, a repeat correction procedure is performed.

It is too early to draw final conclusions about the positive and negative aspects of laser vision correction. It will be possible to talk about the stability of the results when all the statistics on the condition of people operated on 30-40 years ago are processed. Laser technologies are constantly being improved, making it possible to eliminate some of the defects of previous level operations. And it is the patient, not the doctor, who should decide on laser vision correction. The doctor only has to correctly convey information about the types and methods of correction and its consequences.

It often happens that the patient is not satisfied with the results of the correction. Expecting to receive 100% vision and not receiving it, a person falls into a depressed state and needs the help of a psychologist. A person's eye changes with age, and by the age of 40-45 he develops presbyopia and has to wear glasses for reading and near work.

This is interesting

In the USA, laser vision correction can be done not only in ophthalmology clinics. Small points equipped for carrying out operations are located near beauty salons or in large shopping and entertainment complexes. Anyone can undergo a diagnostic examination, based on the results of which the doctor will perform vision correction.

For the treatment of hypermetropia (farsightedness) up to +0.75 to +2.5 D and astigmatism up to 1.0 D, the LTK (laser thermal keratoplasty) method has been developed. The advantages of this method of vision correction are that during the operation no surgical intervention is performed in the eye tissue. The patient undergoes a preoperative examination, and before the operation anesthetic drops are instilled into him.

Using a special pulsed holmium laser of infrared radiation, tissue is annealed on the periphery of the cornea at 8 points with a diameter of 6 mm, the burned tissue shrinks. Then this procedure is repeated at the next 8 points with a diameter of 7 mm. Collagen fibers of the corneal tissue in places of thermal influence are compressed, and the central

Due to tension, the part becomes more convex, and the focus shifts forward to the retina. The greater the power of the supplied laser beam, the more intense the compression of the peripheral part of the cornea and the stronger the degree of refraction. The computer built into the laser, based on the data from a preliminary examination of the patient’s eye, automatically calculates the parameters of the operation. The laser only lasts about 3 seconds. The person does not experience any unpleasant sensations, except for a slight tingling sensation. The eyelid expander is not immediately removed from the eye so that the collagen has time to shrink well. Afterwards the operation is repeated on the second eye. Then a soft lens is placed on the eye for 1-2 days, antibiotics and anti-inflammatory drops are instilled for 7 days.

Immediately after the operation, the patient develops photophobia and a feeling of sand in the eye. These phenomena quickly disappear.

Restorative processes begin in the eye and the refractive effect gradually smoothes out. Therefore, the operation is performed with a “reserve”, leaving the patient with a weak degree of myopia up to -2.5 D. After approximately 3 months, the process of returning vision ends, and the person returns to normal vision. Over the course of 2 years, vision does not change, but the effect of the operation lasts for 3-5 years.

Currently, vision correction using the LTK method is also recommended for presbyopia (age-related vision deterioration). People aged 40-45 years often experience the appearance of farsightedness, when small objects and printed fonts become difficult to distinguish. This happens due to the fact that the steel frame loses its elasticity over the years. The muscles that support it also weaken.

To reduce vision regression based on the LTK method, a technique with a longer-lasting effect of thermal keratoplasty has been developed: diode thermokeratoplasty (DTC). In DTC, a constant diode laser is used, in which the energy of the beam supplied by the laser remains constant, and annealing points can be applied arbitrarily. Thus, it is possible to regulate the depth and location of coagulants, which affects the duration of healing of the corneal tissue and, accordingly, the duration of action of DTC. Also, with a large degree of hypermetropia, a combination of LASIK and DTK methods is performed. The disadvantage of DTC is the possibility of astigmatism and slight pain on the first day of surgery.

Complications after LASIK

and her safety

As we know, LASIK surgery may seem scary at first, but in fact, Opti LASIK ® laser vision correction is fast, safe, and almost immediately afterward, you will finally have the vision you've always dreamed of!

Safety of LASIK eye surgery

Corrective laser surgery is considered one of the most common procedures of choice today. Those who passed it are very happy about it. Results of a survey of patients who underwent LASIK surgery. showed that a whopping 97 percent of them (that's impressive!) said they would recommend the procedure to their friends.

Based on the results of controlled clinical trials conducted in the United States to evaluate the safety and effectiveness of the operation, FDA FDA: Abbreviation for Food and Drug Administration, a federal agency within the U.S. Department of Health and Human Services that is responsible for determining the safety and effectiveness of drugs and medical products. approved LASIK for use in 1999, and since then, LASIK has become the most widely accepted form of laser vision correction today, benefiting approximately 400,000 Americans each year. 1 In 93 percent of cases, patients' vision after LASIK is at least 20/20 or better. The impressive thing is that this operation takes only a few minutes and is almost painless.

Of course, as with any other surgical procedure, there are some safety considerations and complications that you may encounter. Take a quick look at the potential complications of LASIK before making any decisions.

Complications after LASIK

Laser technology and surgeons' skills have advanced significantly over the past 20 years since LASIK was first approved by the FDA in 1999, but no one can accurately predict how an eye will heal after surgery. As with any surgical procedure, there are risks associated with LASIK. In addition to the short-term side effects that some patients experience after surgery (see After LASIK Eye Surgery), some people may experience conditions that last longer due to differences in the healing process between people.

Listed below are some LASIK complications that you should discuss with your surgeon if they occur after surgery.

The need to use reading glasses. Some people may need to use reading glasses after LASIK surgery, especially if they were nearsighted to read without glasses before surgery. They are more likely to suffer from presbyopia - Presbyopia: A condition in which the eye loses its natural ability to focus correctly. Presbyopia is a natural result of aging and leads to blurry near vision. If presbyopia is diagnosed, glasses or corrective contact lenses must be used to maintain quality near vision distances. physiological condition that comes with age.

Decreased vision. Sometimes, indeed, some patients after LASIK note a deterioration in vision relative to previously optimally corrected vision. In other words, after laser surgery you may not see as well as you could with glasses or contact lenses before surgery.

Decreased vision in low light conditions. After LASIK surgery, some patients may not see well in low light, such as at night or in foggy, cloudy weather. These patients often experience halos. Halos: A visual effect - a circular haze or haze that may appear around a headlight or illuminated objects. or annoying glare around bright light sources, such as street lamps.

Severe dry eye syndrome. In some cases, LASIK surgery can result in insufficient tear production to keep the eyes moist. Mild dry eye is a side effect that usually goes away within about a week, but in some patients the symptom persists permanently. When determining whether laser vision correction is right for you, let your doctor know if you have been bothered by dry eye syndrome, have problems with contact lenses, are in menopause, or are taking birth control pills.

Need for additional interventions. Some patients may need enhancement procedures to further correct their vision after LASIK surgery. Rarely, patients' vision changes, and sometimes this can be attributed to an individual healing process that requires an additional procedure (re-treatment). In some cases, people's vision has decreased slightly and has been corrected by slightly increasing the power of the prescribed glasses, but this does not happen often.

Eye infections. As with any surgical procedure, there is always a small risk of infection. However, the laser beam itself does not transmit infection. After surgery, your doctor will likely prescribe prescription eye drops to protect against post-surgery infection. If you use the drops as recommended, the risk of infection is very low.

The FDA does not monitor the conditions of each surgery and does not inspect doctors' offices. However, the government requires surgeons to be licensed through state and local agencies and regulates medical products and equipment, requiring clinical studies that prove the safety and effectiveness of each laser.

To read the supporting material on choosing the right doctor. continue to the next section.

Comments on the review

Andrey June 6, 2012 Anything is possible! I know for sure that a lawsuit is now being prepared against AILAZ, due to the negligence of doctors.

Oksana Sergeevna Averyanova, AILAZ center September 14, 2012 I called and did not specifically find out the name of the patient - the “victim”, or the circumstances of the case. The answer was supposedly from a “representative” of the “affected person.” There have been no calls to our clinic from the court.

Laser vision correction

Messages: 2072 Registered: Sat Mar 26, 2005 04:40 From: Barnaul

My husband recently did this. Seems happy

The postoperative period is three days, the second is the most difficult, because the eyes are watery and hurt, there is increased irritability to light and everything bright, but even that is not scary. There are fewer unpleasant sensations during Lasik surgery, when the epithelial layer is incised and then put back in place (rather than burned out and then a new one grows), but they explained to us that with Lasik there is a greater risk that something will go wrong.

As I understand it, there are no special guarantees that vision will not begin to deteriorate again, this is a minus. On the other hand, for those who do not tolerate lenses well, this is still a solution, even if only for a few years.

I think I will also have surgery on myself, but only after I give birth for the second time, although they say that surgery is not a contraindication for natural childbirth, it’s still scary after giving birth; I personally had red eyes, you never know.

I am collecting reviews about laser vision correction.

If it’s not difficult, I ask those who have undergone laser vision correction to unsubscribe here!

If possible, indicate the degree of myopia (astigmatism, farsightedness), the method of laser correction and when it happened, the sensations during the operation, etc. You can indicate the clinic - what if this helps someone?

The most important thing is the result.

It is quite rare to have pupils of different sizes, but this also happens. In order to understand why this happens, you need to become familiar with the structure of the pupil. So, the pupil is a kind of hole that is formed by the free edges of the iris. The location is not in the center, but slightly shifted inward and downward. The black aperture indicates the retina. The pupil performs the main function of regulating the number of light rays transmitted to the retina. If a person looks at a bright light, the pupil slightly decreases in diameter, due to which the light rays are cut off.

This results in clear images. In the dark, the hole, on the contrary, becomes wider. Constriction of the pupil or dilation is achieved by a muscle that is innervated by sympathetic nerves. But the sphincter muscle is controlled by parasympathetic nerves. Thus, when a person experiences a feeling of fear, severe fright, or pain, the sympathetic nervous system is activated, which is why the pupil dilates. In addition, the pupil can expand when the eyeball turns towards the nose and when looking from an object that is close to a distant image. This is considered the norm. If pupils of different sizes are noted not under such circumstances, then we should talk about a pathology, which is called anisocoria.

Different pupil sizes are divided into two main types - physiological and congenital. Physiological anisocoria is assigned when there is a difference between the sizes of the pupils, but no diseases have been identified. This condition can be attributed to the individual characteristics of the human body. In addition, the disease is divided into subtypes, depending on the age of the person, since the causes are different.

Newborns, children

Pupils of different sizes in a child who has just been born indicate a congenital form of pathology. It may also be a sign of another disease or disorder. For example, if anisocoria occurs suddenly, the cause may be brain injury, the presence of a neoplasm, an aneurysm of the circulatory system in the cranial cavity, or encephalitis. If a child was born with a pathology, the cause may be underdevelopment of the autonomic nervous system or congenital diseases of the iris. As a rule, it is accompanied by drooping eyelids or strabismus. For older children's age category, a different etiology is characteristic. So, the reasons for different pupil sizes in a child are:

1. Injury to any part of the brain or visual apparatus.
2. Previous eye surgeries. Most often in this case, the sphinx or iris is damaged.
3. Encephalitis, meningitis.
4. Inflammatory processes in the iris and vascular aneurysm.
5. Neoplasms in the brain.
6. Intoxication with poisons and overdose when taking medications.
7. Adie's syndrome.

Adult population

Reasons for different pupil sizes in adults:

1. Diseases of an ophthalmological nature. These include uveitis, iridocyclitis, and iritis. Also the consequences after surgery and the presence of an implant in the cavity of the visual apparatus.
2. Causes of a neurological nature with a bright manifestation in the dark. Feature: a pathological deviation includes a pupil that is more constricted (smaller in size). This happens with Eydie, Horner syndrome and non-ischemic damage to the motor nerve fibers of the eye. Horner's syndrome deserves special attention, since it develops against the background of a huge number of pathologies of the brain, cervical spine and cancer. This species is characterized by a delay in pupil dilation during sudden changes in light. For example, when a person goes from a lighted room to a completely dark one.
3. Neurological diseases in which anisocoria is more pronounced in bright light. A pathological disorder is noted in the dilated pupil. This form occurs due to paralysis of the motor nerves of the visual apparatus, which develops against the background of strokes, aneurysms, neoplasms and inflammatory processes in the brain.
4. Another reason for pupils of different sizes may be long-term use of certain groups of medications. For example, anticholinergics or sympathomimetics. Quite often, anisocoria occurs with herpes zoster, which is localized in the ciliary ganglia.

Main symptoms

1. Decreased visual acuity and blurred vision.
2. Split objects and loss of vision.
3. Fear of bright light and headaches.
4. Impaired consciousness and pain in the visual apparatus.
5. Nausea and vomiting.
6. Increased body temperature.

Diagnosis and treatment

In order to diagnose a disease in which pupils of different sizes are noted, you need to consult an ophthalmologist. After a thorough examination, the doctor will prescribe appropriate treatment.

Diagnostics

Diagnosis includes a visual examination of the visual apparatus and instrumental research methods. This may be ophthalmoscopy, magnetic resonance imaging using a contrast agent, or EEG. In addition, the ophthalmologist measures intraocular pressure and examines the cerebrospinal fluid. Additionally, X-rays of the lungs and Doppler sonography of the circulatory system of the brain can be performed.

Treatment methods

The treatment method is prescribed based on the etiology and cause of pupils of different sizes. So, if a congenital or physiological form is diagnosed, then treatment may not be prescribed at all, since this is not considered a pathological deviation. Antibacterial therapy is used for inflammatory processes, and surgical intervention is used for neoplasms. If encephalitis, meningitis and the like are observed, then only comprehensive treatment is carried out. If the disease does not require treatment, but the patient wants to correct the defect, surgery may be prescribed. In many cases, therapy using eye drops may be used. More often. Depending on why pupils of different sizes occur, anti-inflammatory and corticosteroid medications may be prescribed.

ATTENTION! It is strictly forbidden to self-medicate and use eye drops. Remember, drug therapy can only be prescribed by an ophthalmologist after a thorough examination.

Complications

If you do not promptly pay attention to pupils of different sizes, especially in a form that requires surgical intervention, serious disorders may follow that lead to the development of diseases of the eyes, circulatory system and brain. In some cases, the outcome can be fatal.

Procedure LASIK or Lasik(laser in situ keratomileusis), which is usually called simply laser vision correction, is a type of refractive surgery to treat nearsightedness, farsightedness and astigmatism. LASIK is performed by an ophthalmologist using a laser. A laser is used to reshape the cornea to improve visual acuity (the clarity and sharpness of the visible image). LASIK surgery is similar to other surgical corrective procedures such as photorefractive keratectomy (PRK) (also called ASA - advanced surface ablation). Side effects include halos, flashes, trouble driving at night, and dry eyes. LASIK and PRK are superior to radial keratotomy in the surgical treatment of refractive error. For patients with moderate to severe myopia or thin corneas who cannot be treated with LASIK, artificial lens implantation remains a popular alternative. Thus, for some patients, LASIK is an alternative to glasses or glasses.

History of LASIK laser correction

Barraquer's early work

In the 1950s, Spanish ophthalmologist José Barraquer developed microkeratome and keratomileusis techniques in Bogotá, Colombia. In his hospital, he cut thin (one hundredth of a millimeter thick) flaps of the cornea to change its shape. Barraquer also examined how much cornea should be left intact to ensure consistent long-term results. This work was followed by the work of a Russian scientist, Svyatoslav Fedorov (1920–2000), who developed radial keratotomy (RK) in the 1970s and created the first implantable posterior chamber contact lenses (implantable artificial lenses) in the 1980s.

Medical laser

In 1968, Mani Lal Bhaumik developed a carbon dioxide laser at the Northrop Research and Technology Center at the University of California, USA. This was the beginning of the excimer laser, the cornerstone of laser eye surgery. In May 1973, a meeting of the Denver Optical Society of America was held in Denver, Colorado, USA, where Bhaumik announced his success with the laser. He later patented his invention.

Application of medical laser in refractive surgery

In 1980, Rangaswami Srinivasan at the IBM Research Laboratory discovered that an ultraviolet excimer laser could etch living tissue with precision and without thermal damage to the surrounding area. He called this phenomenon “ablative photodecomposition” (APD). Five years later, in 1985, Stephen Trockel of the Edward S. Harkness Eye Institute at Columbia University in New York City published his work using the excimer laser in radial keratotomy. He wrote:

“Central corneal flattening, obtained by radial incisions with diamond scalpels, was duplicated with radial incisions by laser in 18 enucleated human eyes. Incisions made with 193 nm far-ultraviolet light emitted by the excimer laser produced corneal flattening ranging from 0.12 to 5.35 diopters. Both the depth of the corneal incisions and the degree of corneal flattening are related to the laser energy used. Histopathology revealed unusually smooth edges of laser cuts.”

Together with his colleagues, Charles Munnerlyn and Terry Clapham, Trockel founded the company VISX USA inc. In 1989, Marguerite B. McDonald, MD, performed the first refractive surgery on a human VISX eye.

Introduction of LASIK vision correction procedure

Patent

On June 20, 1989, Golem A. Payman received a US patent for LASIK surgery (US4840175). It was like this:

“Method and apparatus for changing the curvature of a living cornea using an excimer laser. A thin layer is removed from the living cornea, leaving the inner surface exposed. The surface or thin layer is then machined with a laser beam along a specified pattern to remove the desired parts. The thin layer is then returned to the surface. Cutting off the central region of the surface or thin layer makes the cornea less curved, while removing the annular region extending from the center of the surface or layer increases the curvature of the cornea. The desired target pattern is formed using an adjustable diaphragm, a variable-sized rotating aperture, a movable mirror, or a movable fiber optic cable through which the laser beam is directed to the exposed inner surface or cut-off thin layer."

Fulfillment in the USA

The LASIK technique was introduced in the United States after successful use elsewhere. The US Food and Drug Administration (FDA) has begun testing the excimer laser. The first company to receive excimer laser approval for photorefractive keratectomy was Summit Technology. In 1992, under the guidance of the FDA, Pallikaris introduced the LASIK technique to ten VISX centers. In 1998, the Kremer Excimer Laser, KEA serial number 940202, was approved by the FDA for the exclusive use of LASIK surgery. Summit Technology subsequently became the first company to receive FDA approval to mass produce and distribute excimer lasers. VISX and other companies followed.

Pallikaris suggested that the corneal flap could be raised with a microkeratome prior to excimer laser PRK. The addition of a flap to PRK has become known as LASIK laser vision correction.

Further developments in LASIK

From 1991 further developments followed, such as faster lasers; contact spots of a larger area; no-scalpel cutting of the flap; intraoperative corneal pachymetry; methods “with wavefront optimization” and “with wavefront control”. However, the use of an excimer laser carries the risk of damaging the retina and optic nerve. The goal of refractive surgery is to avoid permanently weakening the cornea by the incisions and delivering less energy to the surrounding tissue.

Experimental methods

• “Simple” LASIK surgery: LASEK, Epi-LASIK;
• Bowman's sublayer keratomileusis (LASIK with thin flap);
• PRK with wavefront control;
• Advanced artificial lens;
• Femtosecond laser intrastromal vision correction: use of femtosecond correction, such as femtosecond lens extraction, FLIVC or "IntraCOR");
• Keraflex: thermobiochemical solution, CE marked for refractive correction, undergoing European clinical trials for the correction of myopia and keratoconus;
• Laser "Technolas FEMTEC": ablation "IntraCOR" without incisions for myopia; is undergoing clinical trials to correct other myopia conditions.

Procedure process

The procedure involves creating a thin flap over the eye, folding it to reconstruct the tissue underneath using a laser, and moving it into place.

Preoperative procedures

Contact lenses

Patients wearing soft contact lenses are asked to stop wearing them 5 to 21 days before surgery. One industry organization recommends that patients who wear hard contact lenses stop wearing them for a minimum of six weeks, plus an additional six weeks for every three years that hard contact lenses are worn. The cornea is vascular because it must be transparent to function properly. Its cells absorb oxygen from the tear film. Thus, contact lenses with low oxygen permeability reduce the absorption of oxygen by the cornea, which sometimes leads to the formation of new blood vessels in the cornea.

This causes a slight increase in the duration of inflammation and healing time, as well as some pain during surgery due to more bleeding. Although some contact lenses (especially modern rigid gas permeable and soft silicone hydrogel lenses) are made from materials with greater oxygen permeability, which helps reduce the risk of new blood vessels forming in the cornea. Patients considering LASIK surgery are cautioned to avoid excessive contact lens wear. It is usually recommended that they stop wearing contact lenses several days or weeks before LASIK laser vision correction.

Preoperative examination and preparation

In the US, the FDA has approved LASIK for ages 18 and older. More importantly, the patient's eye prescription must not change for at least one year before surgery. Before the procedure, the patient may be examined with pupil dilation and informed. Before surgery, the patient's cornea is examined with a pachymeter to determine the thickness and with a topographer, a corneal topography machine, to measure the contour of the surface. Using low power lasers, the topographer creates a topographic map of the cornea. The procedure is contraindicated if the topographer detects complications such as keratoconus. In the preparatory process, astigmatism and other deviations from the norm in the shape of the cornea are also diagnosed. Using this information, the surgeon calculates the volume and location of corneal tissue to be removed. The patient is prescribed a self-administered antibiotic in advance to minimize the risk of infection after the procedure and is sometimes offered a short-acting oral sedative as preparatory medication. Anesthetic eye drops are administered before the procedure.

Operation

Creating a flap

A soft corneal suction ring is applied to the eye, holding the eye in place. This step in the procedure can sometimes cause small blood vessels to rupture, leading to bleeding or subconjunctival hemorrhage into the white (sclera) of the eye. This safe side effect goes away within a few weeks. Increased absorption causes short-term blurred vision in the treated eye. When the eye is immobilized, a flap is created. This process is achieved with a mechanical microkeratome, using a metal blade or femtosecond laser, which creates a series of tiny, closely spaced bubbles in the cornea. A rod is left at one end of the flap. The flap is folded back to expose the stroma, the middle layer of the cornea. The process of lifting and rolling the flap can sometimes be awkward.

Laser correction

The second stage of the procedure uses an excimer laser (193 nm) to reconstruct the corneal stroma. The laser vaporizes the tissue in a precisely controlled manner without damaging the adjacent stroma. Tissue ablation does not require heat burning or actual cutting. The layers of tissue removed are one-tenth of a micrometer thick. Performing laser ablation in the deeper corneal stroma results in faster visual recovery and less pain compared to the older technique, photorefractive keratectomy (PRK). During the second stage, the patient's vision becomes blurry as the flap is lifted. The patient can only see white light surrounding the orange laser light, which can cause mild disorientation. The excimer laser uses an eye tracking system that follows the patient's eye position up to 4,000 times per second, changing the direction of laser pulses in the treatment area. A typical pulse is about 1 millijoule (mJ) of pulse energy in 10-20 nanoseconds.

Moving the flap

After altering the stromal layer with the laser, the LASIK flap is carefully moved over the treatment area by the surgeon and checked for air bubbles, foreign bodies, and proper fit on the eye. The flap remains in place through natural adhesion until healing is complete.

Postoperative care

Patients are usually prescribed a course of antibiotic and anti-inflammatory eye drops. They continue to take them for several weeks after surgery. Patients are advised to rest and given a pair of tinted eye shields to protect the eyes from bright light and safety glasses to prevent eye rubbing during sleep and reduce dry eyes. They are also required to moisten their eyes with preservative-free artificial tears and follow the instructions for administering the prescribed drops. Patients should be sufficiently informed by their surgeon about the importance of proper postoperative care to minimize the threat of complications.

Wavefront guided LASIK

Wavefront-guided LASIK is a variation of LASIK surgery in which, instead of applying a simple focusing force correction to the cornea (as in the traditional LASIK procedure), the ophthalmologist applies a spatially varying correction by directing a computer-controlled excimer laser with measurements from a wavefront sensor. The goal is to achieve a more ideal eye from an optical point of view, although the final result still depends on the physician's success in predicting changes that occur during healing and other factors that may relate to the uniformity/irregularity of the cornea and the axis of any residual astigmatism. In older patients, scatter from microscopic particles (cataracts or incipient cataracts) may play a role that outweighs any benefit from wavefront correction. Therefore, patients expecting so-called “super vision” from such procedures may be disappointed.

Australian ophthalmologist Noel Elpins, who developed the vector analysis technique to analyze astigmatism in cataract, refractive and corneal surgery, has long advocated combining "vector planning" with the wavefront-guided LASIK procedure. Elpins argued that the purely refractive approach represented by wavefront analysis was contrary to the experience developed over the years in corneal surgery. Refractive surgeons have long known that corneal uniformity is the basis for excellent visual outcomes. Because refractive and corneal topographic astigmatism do not always level out, correction of intrinsic optical errors surgically sculpted onto the cornea can increase corneal irregularity.

Elpins believes that the path to "super vision" requires more individual reduction of corneal astigmatism than is typically attempted, and that any residual astigmatism should be uniform (as opposed to uneven). These are the basic principles of vector planning that are missed in a simple wavefront controlled treatment plan. Elpins' observation was confirmed in a prospective study of LASIK patients, which found a greater reduction in corneal astigmatism and better visual outcomes under twilight conditions using wavefront technology combined with vector analysis (Elpins method) than using wavefront technology alone; equivalent higher order deviations were also found.

No good data have been found to compare the percentage of LASIK procedures that use wavefront guidance versus the percentage that do not, nor the percentage of refractive surgeons who prefer one technique over the other. Wavefront technology continues to be considered an "advancement" in LASIK with purported benefits; however, it is clear that not all LASIK procedures are performed with wavefront guidance.

Surgeons so far say that patients are generally more satisfied with this technique than with previous methods, especially with regard to the less frequent occurrence of “halos,” a visual artifact caused by bispherical deviation that occurred in the eye with earlier methods. Based on their experience, the US Air Force described the wavefront-guided LASIK procedure as providing "superior visual results."

Results of LASIK surgery

The planning and analysis of corneal reshaping techniques such as LASIK have been standardized by the American National Standards Institute, an approach based on the Elpins method of astigmatism analysis. The FDA website states the following regarding LASIK:

Before undergoing a refractive procedure, you should carefully weigh the risks and benefits based on your own value system and try to avoid being influenced by friends who have had the procedure or doctors who encourage you to do so.

Patient satisfaction

Surveys about the LASIK procedure reveal 92-98% patient satisfaction rates. In March 2008, the American Society of Cataract and Refractive Surgery published a meta-analysis of patient satisfaction based on 3000 articles reviewed from international clinical journals. Data from the previous 10 years revealed a 95.4% patient satisfaction rate among LASIK patients.

Controversy regarding safety and effectiveness

The reported safety and efficacy data are open to interpretation. In 2003, the Medical Defense Union (MDU), the largest insurer for doctors in the United Kingdom, reported a 166% increase in claims for laser eye surgery; however, MDU argued that some of these claims are the result primarily of LASIK patients' unrealistic expectations, rather than of faulty surgery. A 2003 study published in the medical journal Ophthalmology", it was found that nearly 18% of treated patients and 12% of treated eyes required retreatment. The authors concluded that larger initial correction, astigmatism, and older age are risk factors for LASIK retreatment. In 2004, the UK's National Institute for Health and Care Excellence (NICE) reviewed a systematic review of four randomized control studies before issuing recommendations for the use of LASIK in the UK's National Health Service (NHS). Regarding the effectiveness of the procedure, NICE said:

Current data on the LASIK procedure for the treatment of refractive errors indicate that it is an effective method for selected patients with mild to moderate myopia,

Data suggest that its effectiveness is lower in severe myopia and farsightedness.

Regarding the safety of the procedure, NICE reported that:

There are concerns about the long-term safety of the procedure and the available evidence is insufficient to support its use in the NHS without specific provisions for consent, audit or research.

Some refractive surgeons in the UK and US, including at least one author of the study cited in the report, suggested that NICE was relying on heavily outdated and poorly researched information. NICE issued revised guidance (IPG164) in March 2006, stating that:

Available evidence suggests that photorefractive (laser) surgery to correct refractive errors is safe and effective for use in appropriately selected patients.

On October 10, 2006, WebMD reported that a statistical analysis found that the risk of infection for contact lens wearers is higher than the risk of infection from LASIK. People who wear contact lenses daily have a 1 in 100 chance of developing a serious contact lens-related eye infection after 30 years of use and a 1 in 2,000 chance of significant vision loss as a result of infection. Researchers estimate that the risk of significant vision loss due to LASIK is approximately 1 in 10,000.

On February 25, 2010, Morris Waxler, a former US Food and Drug Administration (FDA) official involved in the approval of laser vision correction (LASIK) devices, expressed concerns about the risk of serious side effects from LASIK and the original FDA approval process. His concerns regarding the safety of LASIK were discussed in an interview on the program " Good morning America" On January 6, 2011, Waxler demanded that

“The Food and Drug Commissioner has revoked FDA approval (PMA) for all LASIK devices and issued a Public Health Alert with a voluntary recall of LASIK devices to stop the epidemic of permanent eye damage caused by lasers and microkeratomes used for LASIK laser vision correction. »

Waxler stated:

The FDA was not fully aware of LASIK injuries prior to and during FDA reviews of documents filed supporting the safety and effectiveness of LASIK devices under 21 CFR 812 and 21 CFR 814. In addition, LASIK manufacturers and their employees refused to release information on the safety and effectiveness of LASIK devices. effectiveness from their reports to the FDA on investigational exempt devices (IDEs). They also hid LASIK injuries from the FDA in the context of a settlement in countless lawsuits. IDE Clinic-sponsored studies selected the best data and withheld and withheld from the FDA information that clearly indicated that LASIK had an excessive adverse event rate (greater than 1%). These actions were an industry-wide effort orchestrated in whole or in part by manufacturers and their employees to circumvent the law and FDA regulations. I will provide confidential information regarding these matters separately to the FDA's Division of Criminal Investigations.

Patient dissatisfaction

Some patients with poor results from LASIK surgical procedures report significantly reduced quality of life due to vision problems or physical pain associated with the surgery. Patients who have suffered complications from LASIK have created websites and discussion forums where future and past patients can discuss the surgery. In 1999, Ron Link, an RK patient, founded Surgical Eyes in New York City as a resource for patients with complications from LASIK and other refractive surgery. Since then, Surgical Eyes has become the Vision Surgery Rehabilitation Network (VSRN). No patient advocacy organizations have changed their official position on refractive surgery, despite allegations by Morris Waxler, Ph.D., of criminal behavior during the approvals process. Between 1998 and 2006, the US FDA received 140 “negative reports regarding LASIK.”

Higher order deviations

The term "higher order abnormalities" refers to vision problems that require special diagnostic testing and cannot be corrected with regular glasses. Such abnormalities include “flares,” “ghost images,” “halos,” etc. Some patients describe these symptoms after surgery and associate them with the LASIK technique, including flap formation and tissue ablation.

Improvements in LASIK technology have reduced the risk of clinically significant visual impairment after surgery. There is a relationship between pupil size and abnormalities, which may result from unevenness of corneal tissue between the intact portion of the cornea and the portion that has been reshaped. Daytime vision after LASIK is optimal because the pupil size is smaller than the size of the LASIK flap. However, at night, the pupil may dilate so that light passes through the edge of the LASIK flap, causing abnormalities. LASIK and PRK can cause spherical deviation if the laser does not correct enough when moving outward from the center of the treatment area, especially when most of the correction has been done.

Others suggest that higher order abnormalities were present before surgery. They can be measured in micrometers, where the smallest FDA-approved laser beam size is approximately 1000 times larger at 0.65 mm. In situ keratomileusis performed at an older age increases the incidence of higher order corneal wavefront abnormalities. These factors demonstrate the importance of carefully selecting patients for LASIK treatment.

Other side effects

Patient advocacy group USAeyes lists the most commonly reported complications of LASIK as:

Dry eyes from surgery;

· Excessive or insufficient correction;

· Vitamin D deficiency from sun sensitivity and therefore avoidance;

· Fluctuations in visual acuity;

· Halos and flashes occur around bright lights at night. At night, the pupil may dilate and become larger than the flap, leading to changes in the edge of the flap or stroma, causing visual distortions that do not occur during the day when the pupil is smaller. An eye examination for large pupils is performed before surgery, when the risk of this symptom is assessed.

• Ghost images or
• Double vision;
• Sensitivity to light;
• Large pupils;
• Eyelid irritation;
• Striae (wrinkles on the flap);
• Decentred ablation;
• Foreign bodies or growth under the flap;
• Thin or loop flap;
• Induced astigmatism;
• Corneal stretching;
• Floaters in the eyes;
• Epithelial erosion;
• Posterior vitreous compartment;
• The spotted hole occurs with a frequency of 0.3%;
• Light contamination (glare) is another complication commonly reported by LASIK patients.

Dry eyes

Most often, patients after refractive surgery complain of dry eyes. It is reported by some patients in the immediate postoperative and late postoperative period. In 2001, a 48% incidence rate within 6 months of LASIK was reported in Finland. In 2006, a 36% incidence rate at 6 months was reported in the United States. Treatment includes artificial tears, prescription tears, and punctal occlusion. Puncture occlusion involves inserting a collagen plug into the lacrimal canal (the natural drainage of the eye).

Some patients complain of symptoms of dry eyes; despite this treatment, dry eyes may be persistent. The incidence of persistent dry eye is estimated to be 28% for Asian eyes and 5% for European eyes. Approximately 90% of the corneal sensory nerves are separated in LASIK. Sensory nerve fibers in the cornea are important in stimulating tear production. One year after LASIK, the bundles of nerve fibers located under the basement membrane are less than half their normal density. Five years after LASIK, the nerves located under the basement membrane first return to a density that is not significantly different from the density before LASIK. Some patients also experience reactive lacrimation, in part to compensate for chronically decreased basal tear production.

Complications after laser vision correction

Complications of the LASIK procedure are classified as preoperative, intraoperative, early postoperative, or late postoperative:

Intraoperative complications with the flap

The flap complication rate is estimated to be approximately 0.244%. Flap complications (such as displaced flap or folds in the flap requiring translation, diffuse lamellar keratitis, and epithelial ingrowth) are common for lamellar corneal surgery but rarely result in permanent loss of visual acuity. The incidence of these microkeratome-related complications decreases as the experience of the treating physician increases.

Slipped flap

A “slipped flap” is a corneal flap that has separated from the rest of the cornea. The chances of this happening are greatest after surgery, so patients are usually advised to go home and sleep to allow the flap to adhere and heal. Patients are usually given sleep goggles or guards that are worn for several nights to prevent the flap from moving during sleep. A short operation may reduce the chances of this complication because there is less time for the flap to dry.

Particles inside the flap

Particles from the inner surface of the flap" are of uncertain clinical significance. Particles of varying sizes and reflectivities are clinically visible in approximately 38.7% of eyes examined in ocular clear media studies and in 100% of eyes examined in confocal microscopy.

Early postoperative complications

Diffuse lamellar keratitis (LK)

DLC is an inflammatory process with the accumulation of white blood cells in the inner surface between the ASIK flap and underlying the corneal stroma. The American organization USAeyes reports the occurrence in 2.3% of cases after LASIK surgery. It is most often treated with steroid eye drops. Sometimes the eye surgeon will need to lift the flap and manually remove the accumulated cells.

Infection

The incidence of infectious reactions to treatment is estimated at 0.4%.

Keratoconus

Keratoconus is a genetic condition that causes the cornea to thin after surgery. Although preoperative screening screens for this condition, it is possible that in rare cases (about 1 in 5,000) it appears later in life (after 40 years). If it occurs, the patient may need rigid gas permeable contact lenses, intrastromal corneal rings and segments (Intacs), cross-linking of corneal collagen with riboflavin, or corneal transplantation.

Subconjunctival hemorrhage

There are reports of cases of subconjunctival hemorrhage, which is estimated at 10.5%.

Late postoperative complications

The abundant data available on the chances of long-term complications are not yet proven and may change due to advances in experience, instruments, and techniques.

Epithelial ingrowth

The incidence of epithelial ingrowth is estimated to be 0.1%.

Late traumatic flap displacement

Late traumatic flap displacement has been reported seven years after LASIK.

Others

Formation of microfolds

Microfolding is defined as “the most inevitable complication of LASIK, the clinical significance of which appears to be negligible.”

Diagnosis of glaucoma

After LASIK surgery, it may be more difficult to measure intraocular pressure (used to diagnose and treat glaucoma). The changes also affect the calculations used to select the correct artificial lens for cataract surgery. This is known as “refractive surprise.” Preoperative, operative, and postoperative measurements may be helpful.

Rare cases

• Retinal detachment: The incidence of retinal detachment is estimated to be 0.36%;
• Formation of new vessels in the choroid: the incidence of new vessels in the choroid is estimated at 0.33%;
• Uveitis: The incidence of uveitis is estimated to be 0.18%.

Climbers

Although the cornea typically becomes thinner after LASIK surgery due to the removal of part of the stroma, refractive surgeons try to maintain maximum thickness to avoid structural weakening of the cornea. Lower barometric pressure at higher altitudes has not been shown to pose an undue risk to LASIK patients. However, some climbers experience myopic changes at very high altitudes.

Effect on leukocytes and keratocytes of the cornea

There are reports of a decrease in the number of keratocytes (fibroblasts) of the cornea after LASIK laser vision correction.

The onset of senile farsightedness

People with myopia (nearsightedness) who approach a certain age (after age 40 - closer to age 50) when they need reading glasses or bifocals may find that they still need reading glasses even though that they had undergone LASIK refractive surgery. In general, nearsighted people need reading glasses or bifocals later in life compared to emmetropic people (seeing without glasses), but this benefit may be lost if they undergo LASIK. This is not a complication, but an expected result of the physical laws of optics.

Although there is currently no method to completely eliminate the need for reading glasses in this group, it can be minimized by performing a variant of the LASIK procedure called mild monovision. In this procedure, performed exactly like LASIK vision correction, the dominant eye is adjusted for distance vision and the non-dominant eye is adjusted for the patient's reading glasses prescription. This allows the patient to achieve an effect similar to wearing bifocal glasses. Most patients tolerate this procedure very well and do not notice any changes between near and far vision, although a small percentage of patients have difficulty adjusting to the effect of monovision. This can be tested for several days before surgery by wearing contact lenses that mimic the effect of monovision. Recently, a variant of the laser ablation model called "PresbyLASIK" has been developed to reduce or eliminate dependence on reading glasses while maintaining distance vision.

Age Considerations

New advances in surgical vision correction provide patients with more choice. People in their 40s and 50s who are considering LASIK laser vision correction to improve their vision may also consider being evaluated for implantable lenses, especially if there are signs of early stage cataracts.

LASIK is one of the most commonly chosen surgical procedures in the United States today. People's perception of LASIK is based largely on advertising, which deliberately entices patients to undergo surgery without providing patients with information about the risks, side effects and contraindications.

The perceived benefits of LASIK surgery are clear, while the risks and negative effects are not well known to the general public. It is naive to assume that a surgeon who has a financial interest in a patient's choice of LASIK will provide adequate informed consent.

LASIK is irreversible and may result in long-term debilitating complications. In 100% of cases after LASIK, there are harmful effects even in the absence of clinically significant complications. In such a context, the choice of surgery is not acceptable since safer alternatives exist in the form of glasses or contact lenses.

Introduction

When the first lasers received FDA approval for LASIK, few people knew about the complications and long-term safety of the procedure. Early clinical trials did not study the harmful effects of LASIK thoroughly enough. Since that time, a number of medical studies have identified the risks of LASIK. It is now widely reported in ophthalmic medical journals that complications such as dry eye and low-light vision impairment are common and that corneal flap formation permanently reduces the tensile strength and biomechanical integrity of the cornea. In 1999, in the wake of the initial popularity of LASIK, Marguerite B. McDonald, a refractive surgeon emeritus and then the magazine's chief medical editor EyeWorld stated in the editorial: We've just begun to hack into the rising LASIK curve in this country. There will be more than enough surgical techniques to satisfy everyone if we are open to sharing information honestly and openly, and despite attempts at resistance from our colleagues when we offer a different perspective to a patient with unsatisfactory results. Who said, “When the tide comes in, all the boats in the harbor rise?” Today, many prominent refractive surgeons are looking for more acceptable and safer surface ablation techniques, such as PRK and LASEK, which do not create a corneal valve. LASIK still continues to be the most commonly performed procedure.

Dry eye

A report by the American Academy of Ophthalmology published in 2002 stated that dry eye syndrome is the most common complication of LASIK /1/. Refractive surgeons are aware that LASIK induces dry eye, while patients are not fully informed about the etiology, chronic nature and severity of this condition.

“My dry eye after LASIK is not a private problem, as some ophthalmologists say. It is not true. I estimate 10% of the time I am blind due to the pain of not being able to open my eyes. When I had my surgery, I was told that only a small number of patients experience complications with this procedure. This is important evidence that this critical side effect is quite common.". David Shell, a LASIK patient who testified before an FDA panel in August 2002.

Persistent dry eye and quality of life after LASIK
The patient chooses LASIK surgery with the expectation of an improved quality of life. Instead, many live with chronic pain from LASIK-induced dry eye. The FDA website states that dry eye after LASIK can be long-lasting (http://www.fda.gov/cdrh/LASIK/risks.htm). The patient should be informed that LASIK surgery cuts the corneal nerves that are responsible for tear production and that these nerves will no longer return to normal. The inability to sense and respond to dryness can result in damage to the optical surface (eye).

Medical research into the duration and severity (features) of dry eye.
Dry eye disease is a painful, chronic condition for some patients following LASIK surgery. In 2001, Hovanesian, Shah, and Maloney showed that 48% of LASIK patients reported symptoms of dryness at 6 months postoperatively, including ulceration, sharp pain, and sticking of the eyelid to the eyeball.

A Mayo Clinic study published in 2004 found that 3 years after LASIK, corneal nerve density was only 60% of preoperative levels. In 2006, Baylor College of Medicine researchers reported dry eye in 36% of all patients more than 6 months after LASIK and in 41% of eyes with (improved valve coagulation?) /4/. These studies were based on objective medical tests rather than patient surveys, which is important because patients with nerve damage may not experience dryness.

The scientific literature is replete with case reports and reports of LASIK-induced dry eye. This complication is widely known in medicine as the most common complaint of LASIK patients, so the problem is confirmed by expert consensus. Most dry eye treatments provide only partial symptomatic relief. LASIK-induced dry eye cannot be restored. Online advertisements and forums dedicated to patients with dry eye after LASIK are a testament to this widespread complication.

Deterioration of night vision

Millions of LASIK surgeries have been performed in the United States over the past decade. Many patients now suffer from blurred vision at night. Some patients, especially those with dilated pupils, are at risk when driving (cars) at night and can no longer live a normal independent life.

“Every day when I drive to work and listen to the radio, I hear a lot of advertisements, including advertisements for the center where I had surgery, which talk about 95, 98 percent of patients who achieve visual acuity of 20/20 or 20/40 or better. , which is presented as success. I consider this criterion successful. However, sometimes in very weak daylight, vision deteriorates due to glare, halos, numerous image halos due to the fact that I had LASIK with my 8mm pupil...

FDA approval of devices must include not only approval for use within certain limits of myopia, astigmatism, or hypermetropia, but also within certain limits of pupil size, so that use of these devices outside the established limits for pupil size is considered a prohibition of the use of the device ... ". Mitch Ferro, a LASIK patient who testified before an FDA panel in August 2002.

Unfortunately, the FDA turned a deaf ear to this recommendation and did not include pupil size limits in either the approval or the presence of a large pupil as a contraindication for LASIK. Instead, the FDA approved LASIK lasers with a vague note regarding large pupils. It was the FDA's discretion to communicate these notes to patients, but it was not enforced, thereby violating the full informed consent rights of many patients with large pupils.

Deterioration in the quality of vision depending on lighting conditions is often noted by LASIK patients. Patients with a pupil that dilates more than the LASIK treatment area have an increased risk of vision-impairing visual aberrations and loss of contrast sensitivity /5/. Even patients with normal pupil sizes are at risk because the laser loses effectiveness on the slope of the cornea, resulting in a smaller-than-intended optical zone /6/. Newer laser technologies attempt to compensate for this by increasing laser energy around the periphery of the ablation zone, but this method removes more corneal layers, which increases the risk of surgically induced keratectasia /7/.

In a study published in 2004, dark-adapted pupil diameters in refractive surgery candidates ranged from 4.3 to 8.9 mm, with an average diameter of 6.5 mm /8/. This finding explains why many patients have severe night vision aberrations in the first days after refractive keratectomy when small optical zone settings, within 4 mm, are used. In an attempt to overcome the discrepancy between the optical zone and the pupil diameter, the treatment zone was gradually increased over several years. However, even the 6.5 mm zone generally used today does not prevent aberrations in patients with wide pupils, as well as with a high degree of correction and the associated small effective optical zone.

Image deterioration and low-light visual aberrations were predictable after LASIK. These problems have been widely studied and described in connection with previous refractive procedures such as keratotomy and PRK and have been associated with pupil size /9/. If the optical power of the cornea is not constant within the pupil diameter, this results in visual aberrations and loss of contrast sensitivity. After cataract surgery or lens replacement, patients also complain of poor vision at night when the pupil dilates. Even when a phakic intraocular lens is used instead of LASIK for safety reasons, some patients experience persistent interference with night vision.

Public Concern about the Effects of LASIK Surgery
Dr. Leo Maguire warned in advance about the health hazard caused by deterioration of night vision after laser surgery /10/. The following is an excerpt from an editorial published in the March 1994 issue of the American Journal of Ophthalmology:

“I hope the reader will now understand how a patient can have clinically acceptable visual acuity of 20/20 in daylight and remain susceptible to clinically dangerous visual aberrations at night if the patient's visual system must deal with altered refraction, increased glare, reduced contrast detection, and certainly degraded peripheral vision. Four times more people die in car accidents at night than during the day, and this figure is well established. Night driving requires hazardous visual experience in adults without aberrations. When we discuss night vision aberrations, we are talking about the painful effects of refractive surgery."

Brief chronology of the scientific literature regarding night vision impairment after corneal refractive surgery
Factors influencing poor night vision in low light after refractive surgery have been discussed in articles and reported by experts for two decades:

1987 “In order for the patient to have a glare-free zone centered on the fixation point, the optical zone of the cornea must be larger than the entrance of the pupil. The larger the optical zone, the larger the glare-free zone” /11/.

1993 “The diameter of the optical zone should be at least as large as the diameter of the pupil to prevent glare in the foveal region, and larger than the size of the pupil to avoid glare in the parafoveal region” /12/.

1996 “At night, when the pupil dilates, light rays passing through the treated and untreated surfaces of the cornea reach the retina in different places and produce a halo” /13/.

1997 “Calculations of changes in corneal transmission function show that a significant loss of visual resolution due to PRK is acceptable, the effect becomes very significant as pupil size increases” /14/.

1998 “...after PRK, the diameter of the pupil largely determines the number and nature of aberrations” /15/.

1999 “Functional vision changes for the worse with a decrease in contrast and an increase in pupil size” /16/.

2000 “The increase in optical aberrations was significantly related to actual pupil size” /17/.

“Thus, the optical system may have no refractive errors in the center of the pupil and an increasing error in the area adjacent to the center. The resulting image may be clear with a small pupil diameter, but deteriorate as it increases in size” /18/.

2002 “The relationship between pupil size and optical clarity is most important in minimizing this interference in radial keratotomy. In PRK and LASIK, pupil size, diameter and location of the ablation zone are also important factors” /19/.

The LASIK industry fails to make adjustments in response to scientific evidence about the importance of matching the effective optical zone to the patient's pupil size. As a result, many LASIK patients have poor vision in low light conditions.

Iatrogenic keratectasia

The cornea is constantly exposed to normal outward intraocular pressure. Collagen plates of the cornea provide its shape and biomechanical stability. LASIK thins the cornea and tears the collagen plates, significantly weakening the cornea. The result is further protrusion of the posterior cornea, which can progress to a condition known as keratectasia, characterized by loss of corrected visual acuity and possible corneal damage requiring corneal transplantation.

The FDA, laser manufacturers, and refractive surgeons recognize that there must be limits on corneal flap thickness, ablation depth, and optical zone diameter based on corneal biomechanics. When the FDA initially approved the use of lasers for LASIK, a minimum of 250 microns was established for the thickness of the cornea under the flap after LASIK surgery to prevent corneal instability and progressive forward bulging. More recent reports in the scientific literature have shown that 250 microns is not sufficient to guarantee biomechanical stability of the cornea /20, 21/. In response, some surgeons have stopped performing LASIK or increased the residual corneal thickness in their practices. However, the bulk of surgeons continued to adhere to the FDA's original 250 micron rule, even though this limit was shown to be insufficient.

The 250 micron rule is often inadvertently violated during a surgical procedure because the microkeratomes that form the valve in LASIK are poorly predictable and produce valves of varying thicknesses /22/. For this reason, the thickness of the valve must be measured intraoperatively. Most surgeons do not use these important measurements during surgery, putting patients with a thicker-than-expected valve at increased risk.

Keratectasia may develop over the months or years following apparently successful LASIK /23/. Because most cases are underreported, the true proportion of these dramatic complications may remain unknown. The only way to prevent surgically induced keratectasia is to stop LASIK itself. It is important to remember that LASIK is an option (i.e. there is an alternative). There is no medical reason to put patients at risk of vision loss due to a non-life-saving surgical procedure.

Incomplete corneal healing after LASIK

The human cornea is unable to fully heal after LASIK. In 2005, Emory University researchers found persistent pathological changes in all examined corneas after LASIK, including diffuse lamellar keratitis (Saharan sands), separation of the valve from the stromal bed, ingrowth of epithelium under the flap at its edge, clogging of the interface with epithelial cells, and ruptured and randomly oriented collagen fibrils /24/. The study showed that the healing response never completely restores normal corneal stroma.

Another study demonstrated that the LASIK valve produced a residual scar whose tensile strength was only 28.1% of that of a normal cornea, and the valve itself recovered to only 2.4% of the normal value (25). This publication reports that one of the authors raised the valve 11 years after LASIK, again demonstrating long-term weakening at the interface after LASIK treatment. Reports of late cases of valve dislocation confirm that LASIK patients become lifelong vulnerable to traumatic valve injury.

Other complications and reasons for concern

Other vision-threatening complications have been observed as a result of LASIK surgery, such as infections, retinal and macular detachments and tears and hemorrhages, optic nerve damage, diffuse lamellar keratitis, uneven valve, folding and striae of the valves, epithelial defects and epithelial ingrowth . These and other complications can have strong, long-lasting adverse effects.

Bilateral simultaneous LASIK
Performing LASIK on both eyes on the same day is convenient and financially beneficial for the surgeon, but not in the best interest of the patient. In a 2003 survey of members of the American Society of Cataract and Refractive Surgery (ASCRS), 91% of surgeons surveyed did not offer patients the choice to operate on one eye at a time /27/. Bilateral simultaneous LASIK puts the patient at risk of vision loss in both eyes and deprives the patient of the right to informed consent for surgery on the other eye.

Inaccurate IOP measurement after LASIK
Changes in corneal thickness and its biomechanical properties due to LASIK have an impact on IOP measurements, resulting in falsely low values. LASIK patients face a lifelong risk of undetectable ocular hypertension, which can progress to glaucoma. Glaucoma is the leading cause of blindness.

Difficulty in cataract surgery after LASIK
Like all people, LASIK patients will develop cataracts at some point. The altered corneal surface due to LASIK makes it difficult to accurately measure intraocular lens power during cataract surgery. This may result in a “refractive surprise” after cataract removal and will put the LASIK patient at risk for needing repeat surgery.

LASIK results - deterioration of near vision (loss of near vision)
Patients are usually poorly informed that they will need reading glasses after age 40, regardless of whether they have had LASIK or not. Nearsighted patients who have not undergone refractive surgery can still see near naturally after age 40 simply by removing their glasses. LASIK increases the need for reading glasses because it shifts the eye's focus from close to distant. Loss of near vision after LASIK myopia correction affects many everyday activities, not just reading. LASIK patients in their 40s may discover that they simply bargained for some glasses instead of others.

Progressive loss of corneal keratocytes after LASIK
A Mayo Clinic study showed a persistent decrease in corneal keratocyte density after LASIK /28/. Keratocyte cells are essential for the functioning of the cornea. This progressive loss of corneal keratocytes may have long-term effects on corneal stability, refractive stability, and cellular integrity of the cornea after LASIK. Ophthalmologists have discussed that progressive loss of keratocytes may eventually lead to post-LASIK ectasia /28, 29/.

Limited conditions for rehabilitation after LASIK
LASIK is irreversible and additional attempts at visual rehabilitation after failed LASIK are extremely limited. Rigid gas permeable contact lenses can improve vision if the patient tolerates the lenses and can be fitted. The process of fitting contact lenses after LASIK can be expensive, time-consuming, and complicated by LASIK-induced dry eye syndrome. Many patients end up struggling desperately to function with poor vision. In extreme cases, a corneal transplant may be required.

Patient satisfaction

The success of LASIK is determined in the “LASIK industry” by measuring uncorrected visual acuity in bright light. Patients correct their vision to remove glasses or contact lenses and are unaware that this may result in loss of quality of vision. Patient reviews (examinations) generally show high levels of satisfaction with LASIK. However, an alarming number of “satisfied patients” also report complications such as visual disturbances and dry eye.

In the March 1994 American Journal of Ophthalmology, in an editorial already mentioned here, Dr. Leo Maguire warned of misleading patient satisfaction rates:

“Patients who have undergone keratorefractive surgery can be both happy with the result and have degraded vision. How can refractive surgery be a possible healthcare issue if the patient is happy with the result? An integral part of this issue is that a patient without complaints is a patient without decreased vision. This argument has not been thoroughly studied. The keratorefractive literature contains disturbing examples of patients with visual impairments exposing themselves and others to significant risk of night-time motor vehicle accidents and yet being satisfied with the outcome.”

In 2001, a survey of PRK and LASIK patients found that 19.5% reported difficulty working, 27.1% reported adverse symptoms, 34.9% reported optical problems, 33.7% reported impairment due to blinding, and 41.5% reported difficulty with driving /30/.

In one report, researchers argue that factors such as the Hawthorne effect (stadium effect?) and cognitive dissonance may play a role in patient satisfaction with LASIK results [31]. The “stadium effect” has a positive effect on survey results because patients perceive that they are involved in the learning process. Cognitive dissonance is a change in one's attitude or belief in eliminating an internal conflict with the negative consequences of an irreversible procedure.

The LASIK industry says there is no evidence linking poorly performed LASIK to depression or suicide. However, it is likely that if there may be a positive impact on quality of life caused by the apparent success of LASIK, we should also assume that there may also be a negative impact on quality of life caused by unsuccessful LASIK.

Newest technologies

Wavefront-aware LASIK and wavefront optimization with LASIK
The latest laser technologies have been developed to reduce the impact of aberrations and interference in night vision. As the complications of existing technologies received negative public response, there was a push to develop and market alternative technologies. The “real” rate of complications is openly discussed not when the procedure is popular, but when new, “improved” technology is being pushed. The LASIK industry and LASIK surgeons aggressively promote new technologies as “safer and more effective,” blaming older technologies for past complications. Although the introduction of wavefront and wave-optimized LASIK was accompanied by hype, research has shown that these methods actually increase, but do not reduce high-order aberrations, which reduce visual acuity compared to the intact eye /32, 33/. A review of the literature on wavefront LASIK leads to a conclusion that does not support the claim that wavefront LASIK is superior to conventional LASIK /34/. Wavefront, like previous types of refractive surgery, fails to deliver on its promises.

Creation of a valve using a femtosecond laser (Intralace-LASIK).
Mechanical microkeratome blades are associated with complications during valve formation and epithelial damage. Femtosecond laser-based keratome is now being promoted as a safe alternative. Studies have shown that the femtosecond laser creates a valve with less deviation from the predicted value than mechanical microkeratomes. However, this does not reduce the number of most complications associated with the LASIK procedure and, moreover, entails the appearance of severe photophobia /35/ - a complication of this particular technology. The femtosecond laser makes it more difficult to lift the valve than if it were created by a blade, which may result in an increased incidence of valve rupture.

The femtosecond laser keratome requires longer eye fixation during valve formation than the mechanical keratome. Cases of vitreous detachment when using blade microkeratomes exceeded 13% overall, and in patients with high myopia they were more than 21% /36/. Increasing the fixation ring exposure time when using a femtosecond laser is likely to significantly increase these values ​​for vitreous detachment, as well as for other serious complications: retinal detachment, macular hemorrhage, retinal vein occlusion, and optic nerve damage due to LASIK.

Examination of current literature reviews reveals problems associated with the femtosecond laser, namely: malformation of the valve, inflammation of the interface, wrinkling of the valve, infectious keratitis, inflammation of the corneal stroma (corneal syndrome?), delayed healing, macular hemorrhages and the appearance of gas bubbles in the anterior chamber after surgical intervention /37 - 43/. The FDA's Medical Device Adverse Events Database (http://www.fda.gov/cdrh/maude.html) contains a number of reports regarding femtosecond laser keratomas.

Conclusion

Vision has always been considered the most important of all five senses. Loss of vision as a result of the chosen surgical procedure can lead to intense experiences, more severe than from the deterioration of the “perception of other senses.” LASIK surgery is performed on healthy eyes with good corrected vision, therefore LASIK should be held to a higher standard than other medical procedures we choose.

The LASIK failure criteria used should include induced visual disturbances, dry eye, corneal abnormalities, and the psychological impact of a poor outcome.

Patients were denied the full truth about the negative effects of LASIK; therefore, they were unable to provide informed consent. The LASIK industry has been impervious to medical research findings that should improve safety standards. Instead, LASIK surgeons are resisting raising safety standards in identifying groups of potential candidates and protecting themselves from liability.

The American Medical Association endorses certain principles of medical ethics. One of them reads: “The doctor will adhere to the standards of professionalism, will be honest in all professional relationships, will fight to make public the doctor’s shortcomings: both in personal terms and in terms of competence, tendency to lie and fraud, for the purpose of a decent existence(http://www.ama-assn.org/ama/pub/category/2512.html).

The white wall of silence, coined by Dr. Marguerite McDonald in 1999, violates this principle.

In refractive surgery it has been and is now a fact that the patient's interests are placed second only to financial interests. Physicians are ethically required to put the patient's interests first. LASIK is not a necessary surgical procedure, but it certainly harms the eyes of every patient; therefore, this is a violation of the basic doctrine of medicine: “The main thing is to do no harm.” Therefore, the practice of LASIK should be stopped.

Myagkikh A.I.

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This is both a symptom of dangerous conditions and simply a cosmetic flaw. But is it a disadvantage? Rather a highlight, although if the size of the pupils differs very much, it looks quite scary at first glance.

Most people know that the pupils dilate and contract under the influence of light, capturing exactly as much as is needed for more or less normal vision. So, when you see someone’s pupils of different sizes, especially if the difference is insignificant, you should not raise the alarm - you need to ask the person to turn their face to the light and compare the size of the pupils again, perhaps the point was precisely that different amounts of light fell on different eyes Sveta.

If pupils of different sizes differ significantly in light and in twilight, that is, the difference between them greatly increases or decreases, this is already a reason to visit doctors in the near future, even if vision does not suffer.

Using special ophthalmic drops can also dilate one pupil, making the person look scary. In this case, vision will be blurry, even if myopia or farsightedness is not diagnosed. However, the effect of the drops wears off quite quickly, so this condition cannot be called pathological.

Sometimes, as doctors say, such a reaction can be observed to some vaccination vaccines, which, in general, is also quite harmless. On the other hand, a symptom such as pupils of different sizes, the reasons for which are not clear, may indicate serious

Diseases of the eyes, brain and rest of the nervous system.

The first thing to do in this case is to ask the person if he has recently had a head injury. If the answer is positive, it is better to play it safe and go to the hospital, since serious brain damage can lead to a very, very sad outcome, while timely medical assistance can save another life.

Children may have pupils of different sizes due to birth trauma. So a visit to a pediatric neurologist on this issue is mandatory.

If there have been no head injuries, you should immediately visit an ophthalmologist, as well as a neurologist. In the event that specialists do not find any diseases or pathologies in their area of ​​competence, you can continue to surprise people with such an unusual appearance feature. For example, David Bowie has lived with such a twist since he was a teenager when he suffered an eye injury. However, his vision remained the same, and his strange appearance perhaps even added to his popularity.

After various operations, the pupils may also remain different for some time. Usually doctors talk about 1-3 months, but it happens that the full function of the muscle responsible for the dilation and constriction of the pupil is not restored.

It's simple: there is no need to panic when you see different pupils, especially if a visit to the doctors has already given you confidence that there are no diseases or injuries. Well, a cosmetic defect, unfortunately, is almost impossible to remove. And is it necessary, especially if there are no inconveniences?