Analyzing Tomographic Thickness for Detecting Corneal Ectatic Diseases

Keratoconus and other ectatic corneal diseases (ECD) are classically referred as noninflammatory thinning disorders. While ECD are characterized by progressive bulging with steepening and conic protrusion of the cornea, thinning is a hallmark. Clinical diagnosis of moderate to advanced disease is not difficult because of the presence of irregular astigmatism and the development of classic biomicroscopic signs: Fleischer’s corneal epithelial iron ring, Vogt’s striae, Munson’s sign, and Rizzuti’s sign. However, the identification of subclinical mild forms of the disease in patients with normal best spectacle-corrected visual acuity and no other clinical signs is challenging and requires complementary imaging for diagnosis. A comprehensive tomographic evaluation of corneal thickness has become paramount for enhancing the diagnostic accuracy. The goal of this chapter is to present tomographic pachymetric evaluation of corneal architecture and its usefulness for diagnosing keratoconus.