The First Blog in a 4-Part Series
Ever wonder about the origins of Laser Vision Correction? It’s actually a fascinating story, particularly because it was stumbled upon completely by accident. In the 1970’s, a Russian Ophthalmologist, Svyatoslav Fyodorov, removed glass splinters from the eye of a patient involved in an accident.[i] Prior to the accident, the patient was nearsighted and required glasses for distance vision. After the glass splinters were removed, the patient’s vision actually improved. That was the impetus for the development of the first refractive surgery procedure by Dr. Fyodorov, known as Radial Keratotomy (R.K.). R.K. was one of the very first refractive procedures.
To understand how this works, let’s review the functional anatomy of a normal sighted eye in comparison to a nearsighted (myopic) eye. In a normal sighted eye, light rays from an object come into focus directly on the retina.
A nearsighted (myopic) eye, however is anatomically longer than a normal sighted eye. Therefore, instead of light rays coming into focus directly on the retina, they come into focus in front of the retina, which creates a blurry image.
This condition can be improved by putting a concave lens in front of the eye with either eyeglasses or contact lenses. A concave lens is thinner in the middle and thicker around the edges and therefore, light rays that pass through this lens are refracted (bent) in a convergent manner which brings them into focus on the retina.
In order to accomplish this same effect with refractive procedures, since it’s not possible to shorten the eye, the cornea is flattened. In doing this, the light rays from an image have a shorter distance to travel, and can therefore come into focus directly on the retina, without the need for a corrective lens. In R.K., a diamond surgical blade, which could be calibrated to different corneal depths, was used to create radial incisions which flattened the cornea to correct nearsightedness (myopia). These incisions are likened to spokes on a bicycle tire.
Following the accidental finding, Dr. Fyodorov performed many R.K. procedures. From the post operative results of these procedures, he was able to fine tune the R.K. procedure and later predict the number of incisions required to correct different amounts of nearsightedness. Dr. Fyodorov’s data then served as a template for other refractive surgeons. R.K. is one of the earliest, and most widely practiced, refractive techniques from which our current laser vision correction technology evolved. Both LASIK and PRK laser vision correction performed today employ the same concept as the original R.K. procedure: changing the shape of the cornea to correct different refractive errors. The advancement in technology over the years has improved the safety and efficacy of laser vision correction. It has also enabled refractive surgeons to correct not only nearsightedness (as with R.K.), but farsightedness (hyperopia), astigmatism and presbyopia (the need for reading glasses over age 40), as well.