RK, short for radial keratotomy, was a process that involved making incisions in the cornea to correct a patient's vision. The aim of this procedure was to changes the cornea's curvature, which resulted in the cornea being flattened out, which corrected myopia.
While the procedure isn't performed much these days, people that did undergo it would receive a thorough eye exam before any action was taken. Some of the things that would be measured and recorded include astigmatism, the corneal curvature, the cornea's thickness and intraocular pressure. Your eyes would be examined for signs of potential future problems as well as for diseases.
After the above info was taken, it would be entered into a computer program, alongside the patient's age and sex. The programs used provided a range of info about the incisions, including the number of incisions to be made, the depth, position and the length of the incisions.
A series of between four and 16 incisions, sometimes more, were made in the cornea's outer portion or in the mid-periphery. A knife shaped like a diamond was often used to make the incisions, which do not have an impact on the normal viewing zone of one's eyes. Also, major anesthesia was not required to undergo the procedure, but local anesthesia was used because this is what made the procedure nearly painless.
When the patient became comfortable and their eye became numb, the next step was to put a lid speculum in place, as this causes the eyelids to retract. The center of the eye was then marked, but before any incisions were made, the knife that was used was set under the microscope. Accuracy was ensured because a guard is on the instrument.
The diamond shaped instrument was preferred over steel ones. This is because results tend to be unpredictable with steel instruments. At least that's the opinion of many surgeons that performed the procedure back in the 1980s and 1990s.
Additional incisions may have been required if the patient had an astigmatism present. If the astigmatism was severe, then the incisions were made in a specific manner, similar to the pattern of a step-ladder. The incisions were placed in a perpendicular direction, right towards the cornea’s steepest curvature. What this did was create a new surface on the cornea.
Side Effects From RK
There were side effects that occurred from RK. However, they were relatively rare. That being said, some of the rare and potential side effects included:
- Vision that fluctuated, which was especially the case during the first month or two following the surgery.
- A cornea that was weaker and was at risk of rupturing if it was hit directly.
- Sensitivity to light
- Difficulty getting contact lenses into one's eyes
At one point in time, radial keratotomy was frequently used to correct myopia. However, more advanced and effective procedures have come along and RK is not widely used anymore. Some of the procedures that replaced it include Lasik, PRK and Lasek.