Abstract
Abstract: :
Purpose: It is known that tear film on the ocular surface becomes unstable when patients wear soft contact lenses (SCL) or undergo LASIK surgery. If a patient keeps eyes open exceeding tear break–up time, visual function may be deteriorated by induced irregular astigmatism with tear film instability. This situation may occur during various activities, such as driving, computer work, and reading. In this study, we examined visual acuity, corneal topography, and higher order aberration after 10 seconds of eye opening (practical visual performance) in the same patients when they wore SCL and after LASIK. Methods: Six patients who had worn SCL before LASIK were examined by following tests immediately and after 10 seconds of eye opening; 1) functional visual acuity (Continuous Functional Visual Acuity Measurement Device, NIDEK), 2) surface regularity index (SRI) and surface asymmetry index (SAI) (TMS–2N, TOMEY), and 3) higher order aberration (OPD–scan, NIDEK). Results were compared before (with SCL), and 1 and 3 months after LASIK. Results: 1) Functional visual acuity was significantly decreased after 10 seconds of eye opening compared with immediately after eye opening both with CL and after LASIK. There was a tendency that functional visual acuity more decreased when patients wore SCL. 2) SRI and SAI were significantly increased after 10 seconds of eye opening compared with immediately after eye opening when patients wore SCL, but not after LASIK. 3) Higher order aberration did not change after 10 seconds of eye opening either with SCL or LASIK. Conclusions: Our results suggest that prolonged eye opening induces decreased quality of vision in eyes with SCL wear and LASIK surgery. In the conditions of that blink is sustained, such as VDT works and driving, visual performance may be more compromised with SCL wear compared with LASIK.
Keywords: refractive surgery: optical quality • contact lens • cornea: tears/tear film/dry eye