Evaluation of the microstructure of cornea by in vivo confocal microscopy in contact lens wearing and non-contact lens wearing keratoconus patients

PurposeTo compare the microstructure of the central keratoconic cornea in contact lens wearing and non-contact lens wearing keratoconus subjects.MethodsOne hundred and one eyes of 56 keratoconic subjects were compared with control patients who wear contact lenses (22 subjects) and controls who do not wear contact lenses (40 subjects). The keratoconic subjects were assessed in 2 groups: the contact lens wearing keratoconus group (37 patients, 64 eyes, 20 female and 17 male; Group 1) and the keratoconus group comprising subjects who do not wear contact lenses (19 patients, 37 eyes, 9 female, 10 male; Group 2).ResultsThe mean age was 33 ± 12 years in the contact lens wearer keratoconus group, 31 ± 12 years in the non-contact lens wearer keratoconus group, 34 ± 12 years in the non-contact lens wearing control group and 29 ± 10 years in the contact lens wearing control group. Mean basal epithelial cell density was significantly lower in the contact lens wearer keratoconus group (p < 0.001) and in the non-contact lens wearer keratoconus group (p < 0.001) in comparison with controls. The anterior, intermediate and posterior keratocyte densities were significantly lower in both contact lens wearer keratoconic subjects (p < 0.001, p < 0.001, p < 0.001) and non-contact lens wearer keratoconic subjects (p < 0.001, p < 0.001, p = 0.004) as compared to controls. Endothelial cell density was not altered in keratoconic patients.DiscussionThe decrease in basal epithelial cell density and in keratocyte density may highlight the role of apoptosis in keratoconus. Endothelial cell density does not change in keratoconus, but extensive variability in endothelial cell size and shape may be encountered.