Refractive Surgery After Radial Keratotomy (RK)
Serving Los Angeles, Orange County, California and Surrounding Communities
Refractive surgery after radial keratotomy can help improve your vision. It may also decrease or even eliminate the need for any glasses or contact lenses. Radial Keratototmy (RK) was a procedure for treating nearsightedness. It worked by flattening the corneal curvature, which is too steep in myopic eyes. Perhaps you had RK when there was no other option. It probably worked for many years and then gradually reading became a problem. Now perhaps you are wearing even distance glasses, or astigmatism is bothering you. The wonderful surgeon who improved your vision is now retired. So what do you do now?
Dr.Khanna may be able to help. He has helped many patients improve their sight after Radial Keratotomy.
Why RK Was Discontinued in the U.S.
RK consisted of making vertical incisions in the cornea penetrating up to 95 percent of corneal depth. The number of incisions ranged from two to eight depending on your vision prescription. Some surgeons were more aggresive and made 16 or even 64 cuts on the cornea.
These incisions weakened the cornea. The eyes are filled with fluid that exerts outward pressure and a weakened cornea may not be able to keep its curvature against that pressure. That leads to fluctuations in vision between morning and night. Residual astigmatism may also be contributing to glare at night. Sometimes rubbing the eyes can improve vision.
The PERK Study
The U.S. National Eye Institute did a ten-year study called the Prospective Evaluation of Radial Keratotomy (PERK) to evaluate the short-term and long-term effectiveness of one of the RK techniques. Researchers concluded that although RK did improve myopia, its effectiveness varied from patient to patient.
It also demonstrated that there was an annual drift towards corneal flattening which caused the eye to be become gradually more farsighted. The results of this study showed that a post-RK eye was permanently unstable and this led to RK falling out of favor in the U.S.
Challenges in Operating on Post-RK Eyes
- The cornea is very flat – because after RK flattened the cornea, there was the gradual progressive flattening;
- There is astigmatism or irregular astigmatism – conditions that causes blurriness at all distances and are not corrected by curvature changes;
- The posterior curvature is different – the rear corneal curvature varies between patients, affecting surgical outcomes;
- The optical zone is small – the area where surgical changes can be made;
- Ophthalmic diagnostic instruments may not be able to display accurate readings – all instruments presume the cornea being measured has predetermined normal values; but after RK, each cornea is different.
- IOL (Intraocular Lens, such as ReSTOR® or Crystalens®) power calculations may also require modifications because of each post-RK cornea being different.
Restorative Surgical Methods after RK
Despite those challenges, there are various methods to improve vision after RK corneal incisions have been made. They require a corneal surgeon like Dr. Khanna to analyze the exact problem and devise a tailor-made solution.Since a corneal surgeon is trained in multiple technologies, he can combine them to improve your individual vision.
Dr.Khanna can use Wavefront LASIK to enlarge the optic zone and eliminate astigmatism or hyperopia. He can use Intacs to strengthen the corneal cross linkage, which increases the cornea’s rigidity. Intacs are a type of corneal insert.
Rajesh Khanna, M.D., is also skilled in lens exchange surgery. If you have cataracts, special calculations and highly skilled surgery would be required. If you want to see far and near in each eye than PRELEX may be an option (Presbyopic Lens Exchange).
Special tests for Refractive Surgery After Radial Keratotomy (RK)
- Ocular Coherence Tomography of Macula
- Pachymetry Map by OCT
- Color Corneal Topography
- Wavefront analysis
- Manual and Auto refraction repeated at different times of day
- Dilated Eye exam
Treatment options for Refractive Surgery After Radial Keratotomy (RK)
- Combination of PIE and Lasek
The best way to determine what is right for you is to come in for a consultation at the Khanna Vision Institute. Please contact our Orange Country office today.