Technical note: Pre-surgical anisometropia influences post-LASIK binocular mesopic contrast sensitivity function.

PURPOSE: To investigate if pre-surgical anisometropia influences the post-LASIK binocular mesopic contrast sensitivity function (CSF). METHODS: Pre- and post-surgical binocular CSF was measured for 54 patients under mesopic conditions. Data on visual acuity and corneal topography were also obtained. RESULTS: The binocular contrast sensitivity declined significantly (r = 0.86; p < 0.001) with increasing pre-surgical anisometropia. Post-surgical interocular differences in corneal asphericity were also associated with increasing pre-surgical anisometropia. CONCLUSIONS: Pre-surgical anisometropia may be indicative of a possible significant deterioration of post-surgical mesopic binocular CSF, and therefore should be taken into account before surgery in analysing the possible disadvantages and limitations of refractive surgery.

Experiment on PMMA models to predict the impact of corneal refractive surgery on corneal shape: Comment.

Recently, two papers "Dorronsoro et al., Experiment on PMMA models to predict the impact of corneal refractive surgery on corneal shape, Opt. Express 14, 6142 (2006)" and "JR Jiménez et al., Deviations of Lambert-Beer's law affect corneal refractive parameters after refractive surgery, Opt. Express 14, 5411 (2006)" have been published on an important question in corneal refractive surgery: to explain the differences between post-surgical corneal elevation maps and those predicted after theoretical ablation. An analysis of Dorronsoro et al. data demonstrates that the failures in Lambert-Beer's law could be in the origin of shape discrepancies. New models and experimental data on deviations of Lambert-Beer's law might help to minimize post-surgical corneal discrepancies and thus optimise eye emmetropization.

Deviations of Lambert-Beer's law affect corneal refractive parameters after refractive surgery.

We calculate whether deviations of Lambert-Beer's law, which regulates depth ablation during corneal ablation, significantly influence corneal refractive parameters after refractive surgery and whether they influence visual performance. For this, we compute a point-to-point correction on the cornea while assuming a non-linear (including a quadratic term) fit for depth ablation. Post-surgical equations for refractive parameters using a non-linear fit show significant differences with respect to parameters obtained from a linear fit (Lambert-Beer's law). Differences were also significant for corneal aberrations. These results show that corneal-ablation algorithms should include analytical information on deviations from Lambert-Beer's law for achieving an accurate eye correction.