Recurrent keratoconus.
Keratoconus is a progressive, noninflammatory, nonvascular axial corneal ectasia, with unclear etiology and pathogenesis. It has a prevalence of 50-230 per 100,000 and is a bilateral disorder in up to 90% of cases. The onset of keratoconus is usually at puberty and progresses over 10-20 years producing an irregular myopic astigmatism. The treatment depends on the severity of the irregular astigmatism. Advanced keratoconus, which cannot be treated with contact lenses, requires a surgical procedure--either penetrating keratoplasty, epikeratophakia, or thermokeratoplasty. The results of penetrating keratoplasty are good, with success rates of > 90% of the cases. Recurrence of keratoconus following penetrating keratoplasty has been previously reported, based on a clinical diagnosis, and confirmed by histopathological examination. We report the clinicopathologic features of two further cases of recurrent keratoconus.