Distinguishing Between Keratoconus, Forme Fruste Keratoconus, And Normal Eyes Through Analysis Of Corneal Epithelium And Stromal Thickness Maps Using Oct

To integrate objective parameters of the corneal epithelium and stroma obtained with a swept-source OCT (Anterion) for differentiation between normal eyes (N), keratoconus (KC), and forme fruste keratoconus (FFKC).

Rothschild Foundation Hospital - Paris, France

A total of 207 eyes from 207 patients were included and categorized into three groups: N (n = 118), FFKC (n = 31), and KC (n = 58). Eyes were grouped based on objective evaluation (Nidek) and subjective evaluation by the authors. Variables derived from the epithelium and stroma provided by OCT were compared between each group.

 Concerning epithelial parameters, the average thickness of the corneal epithelium was statistically higher in the KC group, showing progression among the three groups (N < FFKC < KC). The thickness of the thinnest point and epithelium in the central zone (0-2mm) was thinner in the KC group with an inferior decentering of the thinnest point. In contrast, epithelial thickness of the 4-6mm ring was statistically higher in the KC group (N < FFKC < KC). Among stromal parameters, average stromal thickness (KC < FFKC < N), minimum thickness (KC < FFKC < N), and stromal thickness from the center to periphery (KC < FFKC < N) were statistically different among the three groups.

Pachymetric maps of the corneal epithelium and stroma obtained through OCT can facilitate the diagnosis of keratoconus, including early cases, which holds particular significance in pre-operative screening for refractive surgery.