Diagnostic Accuracy of Corneal and Epithelial Thickness Map Parameters to Detect Keratoconus and Suspect Keratoconus

Figure 2

The epithelial and topography maps of normal eye, suspect keratoconus, and keratoconus eyes. The green circles overlaid on epithelial thickness maps had diameters of 2.0 mm, 5.0 mm, 7 mm, and 9 mm. The top row was a randomly chosen normal left eye of a 26-year-old female. The topographic simulated K readings were 45.87 D and 47.23 D. The Sirius software classifier provided a normal class. Min-Max ET (2_5) and SN-IT ET (2_5) had normal values (−6 μm and −1 μm, respectively). Case 2 (middle row) was a 20-year-old female with suspect keratoconus in the right eye. Her CDVA was 1.0. The simulated K values were 43.83 D and 50.01 D. The topography map showed inferior steepening. The ET map showed apical thinning inferotemporally. Min-Max ET (2_5) and SN-IT ET (2_5) exceeded cutoff values (−14 μm and 8 μm, respectively). Case 3 (third row) was a 32-year-old female with keratoconus in her right eye. Her CDVA was 0.2. The simulated K readings were 46.61 D and 48.64 D. The Sirius software classifier showed keratoconus class. The ET map showed apical thinning with surrounding thickening. Min ET (0_2), Min-Max ET (0_2), Min ET (2_5), Min-Max ET (2_5), and SN-IT ET (2_5) exceeded cutoff values of detecting keratoconus (37 μm, −10 μm, 38 μm, −26 μm, and 9 μm, respectively). S = superior; T = temporal; I = inferior; N = nasal; K = keratometry; D = diopter; Min-Max = minimum-maximum; ET = epithelium thickness; SN-IT = superonasal-inferotemporal; μm = micron; CDVA = corrected distance visual acuity; Min = minimum.