PRK – photorefractive keratectomy – this method appeared more than 20 years ago. With PRK a laser ray works on the cornea surface; in the result a part of its protective layer, epithelium, is removed, and it takes time to recover it. After the operation a patient feels sensations of pain, watering and photophobia. Vision into the distance is recovered during 3-7 days. Full stabilization comes in 3-4 months.
PRK method is effective for correction of myopia up to –6 diopters, astigmatism up to –3 diopters and farsightedness up to +3 diopters. The operation is usually made not simultaneously on both eyes but with an interval about 7-14 days.
Nowadays this method is restrictedly applied to correct a special, definite pathology of cornea.
Disadvantages of PRK
- Sensations of pain in the eye are felt for 3 days after the operation.
- Vision is restored not at once.
- Full vision stabilization comes only in 3-4 months.
- The operation is not made simultaneously on both eyes.
- PRK can correct myopia only up to –6 diopters, astigmatism up to –3 diopters and farsightedness up to +3 diopters.