The corneal ectasia disorders, such as keratoconus, pellucid marginal degeneration, and postoperative corneal ectasia (keratectasia), share two main attributes: impairment of visual acuity and progressive corneal thinning and steepening that leads to asymmetric anterior and posterior corneal surfaces and irregular astigmatism.1,2 Variation in the thickness of the corneal epithelium can compensate to some extent and thereby mask underlying stromal topographic irregularities.3 For example, in...
