Effect of tear film break-up on higher-order aberrations measured with wavefront sensor

PURPOSE: To investigate whether optical wavefront aberrations vary with tear film break,up. DESIGN: Observational case series. METHODS: Higher order aberrations were examined for 20 eyes of 20 normal subjects with a Hartmann-Shack wavefront sensor before and after tear film break-up. RESULTS: Higher-order aberrations for photopic vision (central 4 mm diameter) after tear film break,up increased 1.44 fold compared to higher,order aberrations before tear film break,up (P = .001, paired t-test). Higher order aberrations after tear film break,up for scotopic vision (central 6 mm diameter) were also 1.23 times higher than those before break,up (P = .005, paired t-test). CONCLUSION: Wavefront sensing enabled us to evaluate the induced irregular astigmatism caused by tear film break,up quantitatively. Wavefront aberrations should be measured carefully to avoid the effects of tear film break-up, especially in wavefront-guided refractive surgery. (C) 2002 by Elsevier Science Inc. All rights reserved.