Abstract
Purpose: :
To dynamically measure wavefront aberration and visual acuity in the dry eye and the normal eyes.
Methods: :
Both right and left eyes of twenty one dry eye patients and fifteen normal subjects were tested for dynamic wavefront aberrations within 45 sec period using the Multi-file mode of a Hartmann-Shack wavefront sensor (WASCA) with a time resolution of one sec. Dynamic visual acuity (VA) was tested for the subjects within 150 sec using a multi-functional VA tester (MFVA-100) with a time resolution about two sec. Eye blink during the test period was also recorded.
Results: :
Every subject showed dynamic change in both the RMS of wavefront aberrations and the visual acuity during the test period, but the change pattern varied substantially from individual to individual. The difference in amplitude of the change in wavefront aberration and VA (Maximum - Minimum) could be as great as 3 times between the subjects. While the dynamic change was blink-dependent for some subjects, relatively stable aberration or VA with eye blink was observed for others. Mean change was greater in the dry eye group than the normal group for either the higher order wavefront aberrations (t=4.12, p<0.00025) or the VA (t=2.92, p<0.005).
Conclusions: :
We have successfully measured dynamic change in wavefront aberrations in the whole eye and the visual acuity with relatively high time resolution. Substantial variation in the patterns of dynamic changes between subjects was observed for both dry eye and normal groups, but the dye eye tends to vary more than normal eye.
Keywords: cornea: tears/tear film/dry eye • aberrations • visual acuity