What is Superficial Keratectomy (SK) and Phototherapeutic Keratectomy (PTK)?
What are the differences between SK and PTK?
SK mechanically removes the diseased epithelium. The front surface of the stroma can be polished with a diamond burr during the procedure to reduce the risk of future corneal erosions.
PTK removes the epithelium using the excimer laser, the same laser that is used in LASIK eye surgery. SK removes only the epithelium while leaving the underlying stroma intact. PTK cannot be made to stop exactly at the stroma, so it also removes some of it. Your doctor will advise you which procedure is likely to do the best for your condition.
What are SK and PK used for?
Opaque or irregularly-shaped epithelium causes blurry vision by not providing a clear or smooth surface for light to enter the eye. SK and PTK improves blurry vision by providing a new smooth, clear layer of epithelium. Sick epithelium tends not to stick well to the underlying cornea and can spontaneously peel off causing corneal erosions. SK and PTK improve these symptoms since the transplanted epithelium more normally adheres to the cornea.
If a patient is planning to have cataract surgery, an irregular cornea surface can make it almost impossible to calculate the replacement lens power or a proper treatment plan. Your doctor may therefore recommend SK or PTK prior to removal of the cataract so that these calculations will be more accurate.
Are SK and PTK painful?
Both procedures are painless since eye drops are used to numb the eye. After the procedure, the eye can be sore, feel scratchy or produce excess tears for several days and then is mildly uncomfortable for another week or so. A bandage contact lens is placed at the time of surgery to reduce postoperative discomfort. This contact lens is kept on the eye for several weeks to months until the eye fully heals.
Are SK and PTK guaranteed to work?
The ability of SK or PTK to improve vision from opaque epithelium is dependent on the severity of the corneal opacification. SK and PTK are successful about 90 to 95% of the time in stopping painful erosions.
What are the risks of SK and PTK?
The main risks include infection and corneal scarring. Antibiotic drops are therefore prescribed to help prevent infection. If a patient’s cornea is healing too slowly or developing scarring after their procedure, the doctor will likely start therapies to help with this. Treatment to lessen scarring is also generally given at the time of the procedure. A very low percentage of patients will need more cornea surgery, including possible cornea transplantation, to remove visually significant scarring.