SHORT-TERM AND LONG-TERM REPEATABILITY OF VISIOPTIC ALCON EYEMAP (VISIOPTIC EH-270) CORNEAL TOPOGRAPHER ON NORMAL HUMAN CORNEAS

The purpose of this study was to examine the shortterm and long-term ( 6 months) repeatability of the Alcon EyeMap (Visioptic EH-270)(a) Comp uterized Corneal Topographer on normal eyes. Three measurements were t aken on both eyes of 39 subjects with the corneal topographer. Both ey es of seven of these subjects were measured 6 months later in order to evaluate long-term repeatability. The data showed that short-term rel iability of the instrument was acceptable with a mean standard deviati on (SD) less than or equal to 0.5 D up to 3 mm (6-mm optical zone) fro m the center of the normal cornea. Beyond that distance, SD's of repea ted measures increased systematically, making the results less useful. Long-term repeatability of the instrument over a 6-month period was a cceptable clinically, although statistically significant differences w ere noted.