A common indication for keratoplasty is keratoconus. The eye-care practitioner must decide when to recommend keratoplasty for the keratoconic patient. This is often not a simple, straight-forward decision.
Keratoplasty for keratoconus is highly successful; however, there is a long recovery period and a risk of severe ocular complications. A number of factors must be considered in deciding when to do a keratoplasty. One of the most important is the patient’s functional vision.
If the best acuity with their contact lenses prevents them from doing their job or carrying out their normal activities, a transplant must be considered. The actual measured visual acuity may be quite different for different patients.
Precise contact lens fittings are necessary before recommending a corneal transplant. One study found that 69% of keratoconics, most referred for transplant, could be successfully fit with contact lenses if special lens designs were used.
Thus, prior to transplant, every effort should be made to optimally fit the patient with contact lenses, especially if there is not significant corneal scarring affecting vision. However, a few patients become intolerant to contact lenses and require a transplant earlier than otherwise would be necessary.
If the patient has a large area of thinning, a very decentered cone, or significant blood vessel growth into the usually clear cornea, called neovascularization, a transplant may be performed earlier than otherwise indicated by the visual performance, as these factors may require a larger than normal transplant button size and/or increase the chance of rejection if allowed to advance too far.