CENTRAL CORNEAL ENDOTHELIAL-CELL CHANGES OVER A 10-YEAR PERIOD

Purpose. To obtain longitudinal data to estimate longterm morphometric changes in normal human corneal endothelia. Methods. Ten years after an initial study, the authors rephotographed the central corneal endot helium of 52 normal subjects with the same contact specular microscope . ;The findings for the 10 subjects younger than 18 years of age a: th e initial examination were considered separately. For the remaining 42 adult subjects, the time between examinations averaged 10.6 +/- 0.2 y ears (range, 10.1 to 11 years). At the recent examination, these subje cts' ages averaged 59.5 +/- 16.8 years (range, 30 to 84 years). Outlin es of 100 cells for each cornea were digitized. Results. For the 42 ad ult subjects, the mean endothelial cell density decreased during the 1 0.6-year interval from 2715 +/- 301 cells/mm(2) to 2539 +/- 284 cells/ mm(2) (P < 0.001). The calculated exponential cell loss rate over this interval was 0.6% +/- 0.5% per year. There was no statistically signi ficant correlation between cell loss rate and age. During tile 10.6-ye ar interval, tile coefficient of variation of cell area increased from 0.26 +/- 0.05 to 0.29 +/- 0.06 (P < 0.001), and the pelcentage of hex agonal cells decreased from 67% +/- 8% to 64% +/- 6% (P = 0.003). For the 10 subjects 5 to 15 years of age at the initial examination, the e xponential cell loss rate was 1.1% +/- 0.8% per year. Conclusions. Hum an central endothelial cell density decreases at an average rate of ap proximately 0.6% per year in normal corneas throughout adult life, wit h gradual increases in polymegethism and pleomorphism.