The effect of diabetes mellitus and retinal laser photocoagulation on corneal parameters: a specular microscopic study

Objectives: The aims of this study were to compare the endotelial structure and central corneal thickness in diabetic and non-diabetic subjects, and to evaluate the effect of retinal laser photocoagulation in patients with diabetic retinopathy on endotelial structure and central corneal thickness. Methods: Subjects were recruited from Al-Naser Eye Hospital, 110 eyes were examined and classified into three groups: diabetic, non-diabetic and diabetic retinopathy treated with laser photocoagulation. The endotelial structure was examined for cell density, coefficient of variation of cell área, percentage of hexagonal cells and central corneal thickness. Images were obtained and analyzed by specular microscope. Results: The mean central corneal thickness was statically thinner in diabetic than in non-diabetic subjects (498 mm versus 505 mm, p=0.029), no differences were observed between diabetic and non-diabetic groups with regard to the mean of coefficient of variation of cell size (p=0.410), mean hexagonality percentage (p=0.076), average cell size (p=0.214) and endotelial cell count (p=0.268). There were no statistically significant differences observed between diabetic and diabetic retinopathy subjects treated with laser photocoagulation in regard with specular microscopy parameters (p= 0.512). Conclusion: Diabetes mellitus has no clinical effects on corneal parameters; besides retinal laser photocoagulation is a relatively safe procedure without a pathological effect on corneal endothelium.