Spontaneous alterations of the corneal topographic pattern.
OBJECTIVE
To assess whether the type of corneal topographic pattern is stable during a 1-minute pause in blinking in healthy subjects.


METHODS
First Department of Ophthalmology, Semmelweis University, Budapest, Hungary.


METHODS
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 instrument in a prospective observational study. The topographic pattern of each image was assessed from the color-coded topographic map and classified into 5 groups (in order of decreasing regularity: round, oval, symmetric bow-tie, asymmetric bow-tie, and irregular).


RESULTS
During the 60-second period, a change in the type of topographic pattern was found in 19 subjects (53%), whereas in 17 subjects (47%) the pattern was stable. The alteration of the topographic pattern was statistically significant (P<.001).


CONCLUSIONS
Immediately after blinking, the ocular surface regularity improves, possibly due to the building up of the tear film. This is followed later by the distortion of the ocular surface, which is the precursor of the tear-film break up phenomenon. Because of these changes, even in healthy eyes, the optimization and standardization of the postblink time of topographic image capture are very important, especially for planning refractive surgery.
Erdélyi
Béla
B
First Department of Ophthalmology, Semmelweis University, H-1083 Budapest, Hungary.
Csákány
Béla
B
Németh
János
J
D000328:Adult; D001767:Blinking / Q000502:physiology; D003315:Cornea / Q000033:anatomy & histology*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D013997:Time Factors