Astigmatic Keratotomy Complications

Introduction:

Astigmatism is a common eye problem causing distorted or blurred vision caused due to irregularities in the shape of the cornea or lens of the eye. Under normal circumstances, the lens and cornea have a smooth and cylindrical shape. Therefore it allows incoming light to focus onto the retina accurately behind the eye. However in patients affected with astigmatism, the cornea or lens is irregularly curved, which leads to refraction of light rays unequally. This unequal refraction causes the formation of two different focal points for the light and causes blurry vision at all distances. Astigmatism can cause deteriorating effects in both nearsightedness and farsightedness. Astigmatism is classified into corneal and lenticular astigmatism. If there are irregularities with the cornea then it is called corneal astigmatism, and the lens irregularities are categorized into lenticular astigmatism. It is diagnosed by an ophthalmologist or sometimes an optometrist can find it.

Various treatment options exist for this which include prescription eyeglasses, refractive procedures such as LASIK (laser-assisted in situ keratomileusis) or PRK (photorefractive keratectomy), and contact lenses can also be used. These treatments are aimed at compensating the curvature in the lens or cornea thereby improving vision and reducing symptoms of astigmatism. Astigmatic keratotomy is a surgery that is done to correct astigmatism and it involves making an incision in the cornea to reshape its curvature. Like any procedure, this also has complications associated with it.

What Are the Complications of Astigmatic Keratotomy?

Astigmatic keratotomy (AK) is a surgical technique that is used in correcting astigmatism by making an incision in the cornea for the purpose of reshaping its curvature either in the cornea or lens. It is generally considered to be safe by the surgeons. However, like any surgery, it comes with a few complications that may arise.

Over the decade, advancements in surgical procedures have minimized complications related to surgeries. Serious complications of this procedure can threaten vision due to bacterial keratitis (infection of cornea caused by bacteria), rupture of the globe (eyeball), endophthalmitis (inflammation of intraocular fluids), and cataract formation. In the initial months following surgery, patients infrequently experience light sensitivity and a fluctuation in visual acuity. Mild glare is common after this surgery and it is rarely found to be disabling the individual. Diurnal variation in visual acuity and refraction is frequently experienced although the event of fluctuation is not significant enough to require additional glasses.

Following are the side effects and complications of this surgery:

1. Overcorrection or Under-Correction: In some cases, surgical outcomes cannot be comprehended and the vision problem may be over or under-corrected. Overcorrection can be due to the cornea being excessively flat, and under-correction can be due to astigmatism not being addressed completely during the procedure. This will result in residual astigmatism and a lesser outcome in visual improvement.

2. Induced Astigmatism: Astigmatic keratotomy involves the use of precise incisions in the cornea or lens and if these incisions are not placed accurately or if the healing is incomplete, it can worsen or induce astigmatism rather than correcting it.

3. Flap Complications: If a partial thickness flap is created for this procedure, there are certain risks for complications to develop. These include flap dislocation, flap-related infections, and epithelial ingrowth. Epithelial ingrowth can be due to abnormal growth of surface cells under the flap.

4. Corneal Scarring: The healing process post the astigmatic keratotomy procedure can take longer and lead to corneal scarring. This can hamper the vision and affect the overall progress of the procedure.

5. Dry Eye Syndrome: Astigmatic keratotomy may disrupt the corneal nerves and affect tear film stability, thereby causing dry eye syndrome. This can result in discomfort and visual disturbances.

6. Infection: It is a rare complication of this procedure. Strict adherence to preoperative preparation, sterile techniques intraoperatively, and appropriate postoperative care can minimize this compilation.

How to Manage the Complications of Astigmatic Keratotomy?

Complications of astigmatic keratotomy are managed in the following ways:

1. Overcorrection or Under-Correction: In cases of overcorrection or under-correction following an astigmatic keratotomy procedure, various treatment options are considered for correcting vision. These include using eyeglasses, prescription contact lenses, and additional surgical procedures to correct vision. It is crucial to consult an ophthalmologist to assess the extent and need of correction required and he or she will recommend the most suitable approach.

2. Induced Astigmatism: Induced astigmatism that occurs due to worsening during surgery for astigmatism needs additional surgical procedures to correct the vision. These will involve further modification of incisions through a second surgery compensating for the induced astigmatism with the use of contact lenses or prescription glasses, considering alternative refractive procedures such as PRK (laser vision correction) or LASIK if deemed appropriate by the treating physician.

3. Flap Complications: In the case of flap complications, arising because of the corneal flap that was created during the astigmatic keratotomy procedure, immediate intervention is necessary. The specific issue will determine the appropriate course of action, which includes repositioning or removing of flap or undertaking further surgical procedures to address the complications that arise because of this which includes dislocation, epithelial growth, or infections. Regular follow-up visits with an ophthalmologist are important to monitor the healing process and ensure appropriate management.

4. Corneal Scarring: If astigmatic keratotomy leads to complications like corneal scarring, specialized treatments like corneal collagen cross-linking (for corneal tissue strengthening) or other techniques may be considered to alleviate or manage scarring. An ophthalmologist will evaluate the extent of the scarring and determine the most suitable approach.

5. Dry Eye Syndrome: In the event that astigmatic keratotomy develops dry eye syndrome, conservative measures can be recommended to manage dryness and promote tear film stability. These can be done by adapting to measures like using artificial tears, using lubricating ointments and gels, making lifestyle modifications such as reduction of eye strain (taking regular breaks from screen time and using digital devices), and in certain instances, pharmacological management along with advanced dry eye therapies.

Conclusion:

An important factor before undergoing an astigmatic keratotomy procedure is the discussion of potential risks, complications, and benefits of the surgery beforehand. If complications may arise, it is crucial to seek the help of an experienced ophthalmologist who will evaluate specific complications, provide an appropriate treatment plan, and choose the correct approach for managing the complications. They will also help in guiding the patients based on individual circumstances, as for each individual the results of surgery may vary. Regular follow-up visits and open communication with the treating physician will help the physician plan the appropriate treatment approach and also improve surgical outcomes.