A few corneal surgeons have suggested that corneal transplantation should be performed for early keratoconus as soon as contact lens wear becomes necessary for satisfactory vision. Although graft survival is excellent, graft rejection episodes are not uncommon in young keratoconus patients. Most corneal surgeons believe that keratoplasty should not be performed in keratoconus patients if the patients can still be fitted safely and comfortably and obtain good optical quality with contact lenses. Topographical analysis of the central 6 to 8mm of keratoconic corneas has permitted fitting custom-made contact lenses in patients with cones as steep as 80D while still maintaining apical clearance. Except in those extreme cases, the Rose K contact lens fitting sets and designs have facilitated fittings for most keratoconus patients and enabled many patients to avoid surgery.
Apical clearance is essential to avoid apical scarring as a complication of contact lens wear.
Fitting contact lenses with adequate tear exchange and good oxygen permeability also is required to avoid oxidative damage. Keratoconic corneas have been shown to lack some of the enzyme activities necessary to process free radicals to prevent severe oxidative damage. Those abnormal wound healing processes and responses to metabolic stress in keratoconic corneas with biochemical and molecular abnormalities cause many corneal specialists to not recommend intracorneal ring insertion. It is well known that deposits accumulate over time in the lamellar channels around the rings even in normal corneas. This deposition has been postulated to be caused by metabolic stress of the keratocytes.