Is Corneal Transplant Needed in Keratoconus Patients?
|Scarring on the cornea|
Keratoconus we know can cause deterioration of vision due to the high nearsightedness and astigmatism brought about by the irregular corneal surface. You can imagine a road with a hilly peak. When keratoconus progresses, that peak can have scarring which makes the vision turn worse. Oftentimes patients would just see shapes and shadows and have difficulty recognizing images. At this time, it seems discouraging, but before jumping into the decision of a definite corneal transplant, why not try to have contact lenses fitted? In a more advanced condition, the contact lens of choice will be scleral lenses. Unlike small gas permeable lens which can pop out and be unstable in advanced cases, scleral lens vaults the entire cornea and so is stable and comfortable on eye. Scleral lenses make the cornea artificially smooth, allowing better quality of light rays to enter the eye. With corneal scars, one should not expect a 20/20 perfect vision, however, most often than not, vision can still reach about 20/40-20/50, which is about 5 to 6 lines on the normal Snellen chart. Though not perfect, this vision is enough to improve one’s functionality. Corneal transplant is a procedure where either the cornea is replaced entirely or in portion. Vision after the transplant in keratoconus patients is very promising with 85% having better than 20/40 vision1; however, corneal transplants are preferably delayed especially in younger patients. Although the survival rates of grafts in keratoconus cases are quite high, studies show that the survival of graft corneas in these patients would be about 20 some years.2 Therefore, an individual who had corneal transplants very early in life would expect to have more than 1-2 transplants in his lifetime.
Corneal transplantation in keratoconus patients is usually reserved in cases where the cornea is too thin, vision can no longer be improved even with contact lenses, contact lenses are unstable and pop out already or if patient cannot tolerate contact lens wear. An extra mile of scheduling a contact lens fitting can make a big difference in the future of younger keratoconus patients.