subject: Long Term Effects of LASIK and PRK Are Encouraging [print this page] Author: Jay Stockman Author: Jay Stockman
The long term side effects of refractive surgery have been a concern for all patients and doctors alike. When Radial Keratotomy(RK) was being performed; there were many unknowns. Flattening the corneas with radial corneal incisions stretched the endothelial layer decreasing its' ability to pump water out of the cornea. While most RK surgeons were not worried about the long term corneal hydration, questions did remain as to what would occur years after the procedure.
These RK patients do have corneal issues 10 plus years later. Their corneas often display a brownish line in the bottom half indicating iron left behind when the endothelial pump removes fluid from the cornea. In addition, most of these patients are far sighted with astigmatism and their prescription gets stronger later in the day. This makes it difficult to have an accurate eye glass prescription. Weakness of the cornea also increases the risk of corneal rupture when exposed to trauma.
LASIK and PRK do not flatten out the entire width of the cornea thus leaving the endothelial layer intact. This does not affect the pump or the functioning of the physiology of the corneal tissue. Therefore negative corneal changes that are displayed in RK patients should not occur in the LASIK and PRK patients.
According to an article published in the November issue of the Archives of Ophthalmology, there are no long term destructive corneal effects following LASIK and PRK. The study examined 29 myopic LASIK and PRK patients 9 years after the surgery and found them to display no abnormal changes. There was a 5.3% decrease in the endothelial cell density which corresponds to a normal cell decrease in individuals that never had the refractive procedure.
While the study did not examine far sighted post operative patients, they concluded that the results would be similar to the near sighted patients. Whereas post operative RK patients displayed corneal changes after 5 years, the LASIK and PRK patients did not show any signs after 9 years. Further studies must be conducted at longer post op intervals to fully examine the long term effects, but this initial study is very encouraging.About the Author:
