Abstract
Purpose::
To evaluate the visual effects of correcting higher-order wavefront aberrations in post-LASIK subjects using adaptive optics.
Methods::
Ten subjects were selected according to the following main criteria: myopic LASIK surgery performed at least three month before the experiment, preoperative myopia above 2.5D, age between 18 and 40. A crx1 adaptive-optics simulator (Imagine Eyes, France) was used to measure visual acuity in the subjects' right eyes in three configurations: 1) the device was set to an aberration-free system so that only the eye's aberrations were present; 2) the adaptive-optics was compensating for the eye's second-order aberrations; 3) all aberrations up to the 5th order were corrected. Sequences of Landolt C optotypes were generated by the Freiburg Acuity Test (Prof. Michael Bach, Germany) and presented at the crx1 internal microdisplay under a luminance of 50 cd/m2. The same measurements were performed using low (10%) and high (100%) contrast optotypes. The tests were conducted in a randomized order and each measurement was repeated twice. All experiments were conducted in natural pupil conditions under dim room illumination.
Results::
Low and high-contrast monocular visual acuities were significantly improved, respectively by 0.11 and 0.05 LogMAR in average, by correcting the second-order aberrations (Wilcoxon p<0.05). Further improvements in average visual acuity were observed when changing from second-order to full (orders 2 to 5) aberration correction. However, only the average increase of 0.07 LogMar in low-contrast acuity was found to be statistically significant (Wilcoxon p<0.05).
Conclusions::
The visual acuity of post-LASIK subjects is enhanced by correcting their residual spherical and cylindrical refractive errors. Low-contrast visual acuity is further enhanced when higher-order wavefront aberrations are also corrected.
Keywords: refractive surgery: LASIK • refractive surgery: optical quality • visual acuity