Purpose:
It is well known that rigid contact lens wear affects cornealshape. Nevertheless previous studies of the shape of keratoconiccorneas included many rigid contact lens wearers. In this study,we evaluated corneal shape indices in keratoconics but excludedthose who had previously worn contact lenses. We compared theseto normal corneas.
Methods:
We retrospectively analyzed the corneal topography (KeratronScout) and tomography (Orbscan IIz) of 97 keratoconic patients(182 eyes) who had no history of contact lens wear and 97 non-contactlens wearers (194 eyes) who had no apparent corneal disorders.
Results:
Five percent of keratoconic eyes showed a claw-shaped topographypattern. The keratoconic group showed significantly steeperand thinner corneal indices than the control group, includinganterior best-fit sphere (BFS), posterior BFS, minimal thickness,center thickness, and mean peripheral thickness. The keratoconicgroup also showed significantly higher elevations from bothanterior and posterior BFS compared to the control group.
Conclusions:
Claw-shaped patterns were observed with keratoconus. Compareto normal corneas, keratoconic eyes were thinner, at not onlycentrally (including the apex) but also in the periphery. Inkeratoconic eyes, the elevations from BFS were more prominentin the posterior than anterior surface.
Keywords: keratoconus • cornea: clinical science • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology