Spontaneous alterations of the corneal topographic pattern

Abstract

This prospective observational study determined whether the type of corneal topographic pattern is stable during a 1-minute pause in blinking in healthy subjects. Corneal topographic images were recorded 5, 15, 30, and 60 seconds after a complete blink in the right eyes of 36 healthy subjects using the TMS-1. The topographic pattern of each image was assessed from the color-coded topographic map and classified into five groups in order of decreasing regularity: round, oval, symmetric bow-tie, asymmetric bow-tie, and irregular. During the 60-second period, a change in the type of topographic pattern was found in 19 (53%) subjects, whereas in 17 (47%) subjects the pattern was stable. The alteration of the topographic pattern was statistically significant (P < .001). The authors believe that these changes are related to alterations of the ocular surface related to tear-film break up phenomenon. They conclude that their results dispel dogma that the corneal topographic pattern is stable in a normal eye. Inasmuch as the corneal topographic appearance is an integral part of the decision to perform refractive surgery, and statistically significant changes in this pattern may occur during the 1-minute interval between blinks, the authors believe it is very important to optimize and standardize the post-blink time of topographic image capture.—Michael D. Wagoner