Age-related changes in corneal thickness and endothelial characteristics

Purpose: To determine the influence of age on central corneal thickness (CCT), endothelial cell density (ECD), average cell size, coefficient of variation in cell size, and percentage of regular hexagonal cells; and to estimate the average ECD and CCT in seven age groups. Materials and methods: After obtaining informed consent, 211 Caucasian patients (358 eyes) were examined using a noncontact specular microscope at the Center of Eye Diseases in Vilnius University Hospital Santariskiu Clinic. The main corneal parameters were: ECD, average cell size, coefficient of variation in cell size, percentage of regular hexagonal cells, and CCT. Subjects (20-89 years) were stratified by age into seven groups. Correlations between CCT, endothelial parameters (ECD, percentage of regular hexagonal cells, average, coefficient of variation), and age were found. Student's t-test and Pearson's correlation coefficient (r) values were calculated. Results: A total of 114 (54.03%) women and 97 (45.97%) men participated in the study. Average ECD (cell/mm(2)) ranged from 2,931 (+/- 371) in 20-29 year olds to 2,222 (+/- 182) in 80-89 year olds; CCT (mu m) ranged from 563 (+/- 44) in 20-29 year olds to 540 (+/- 35) in 80-89 year olds. A strong inverse correlation was observed between age and corneal ECD (r=-0.650, P < 0.01) and a weak inverse correlation was observed between age and CCT (r=-0.156, P < 0.01). ECD and CCT correlated directly (r= 0.232, P < 0.01). The average size of corneal endothelial cells directly correlated with age (r=0.586, P < 0.01). There was no correlation between age and the coefficient of variation in cell size nor the percentage of regular hexagonal cells (P > 0.05). Conclusion: Young people have higher ECD. CCT also decreases, but its dependence on age is weaker. A lower cell density indicates a thinner cornea. The variation in cell size and percentage of regular hexagonal cells are not dependent on age.