Keratocyte Density in Clinically and Topographically Normal Eyes of Patients With Unilateral Keratoconus

Abstract

Purpose: : To evaluate keratocyte density in the fellow eye of unilateral keratoconus and compare it with keratocyte density in eyes of normal subjects.

Methods: : Nine clinically and topographically healthy eyes of patients with unilateral keratoconus (study group - Group 1) and 12 eyes of age matched normal subjects (control group - Group 2) were examined by in vivo corneal confocal microscopy. Inclusion criteria in the study group were clinical signs of keratoconus and marked asymmetric bow tie pattern in the topography of one eye, and absence of clinical signs and normal topography without any asymmetry in the fellow eye. Twelve refractive surgery candidates were used as controls. Confocal microscopy was performed (HRT II, Rostock Cornea Module, Heidelberg Engineering) and keratocyte density was evaluated in respect to the: anterior stroma, mid stroma and posterior stroma. Results were analyzed by non parametric tests.

Results: : Keratocyte density was lower in all layers of group 1 eyes when compared with normal controls. Median values and range in anterior corneal stroma of eyes in group 1 and controls respectively was: 454 cells/mm² (from 315 to 876 cells/mm²) and 612 cells/mm² (from 494 to 715 cells/mm²), p= 0.007; in mid corneal stroma of eyes in group 1 and controls: 231 cells/mm² (from 197 to 344 cells/mm²) and 326 cells/mm² (from 288 to 339 cells/mm²), p=0.003; in deep corneal stroma of eyes in group 1 and controls: 246 cells/mm² (from 207 to 327 cells/mm²) and 328 cells/mm² (from 307 to 402 cells/mm²), p=0.001.

Conclusions: : Topographically healthy eyes of patients with unilateral keratoconus have lower keratocyte density than normal eyes in all stromal layers. These eyes may have a higher probability to develop keratoconus and this may be associated with the reduced keratocyte density which they demonstrate.

Keywords: cornea: stroma and keratocytes • keratoconus