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J.R. Jimenez, R.G. Anera, L. Jimenez del Barco, R. Gutierrez, C. Villa; Interocular–differences In Corneal Asphericity And Aberrations Diminish Binocular Contrast–sensitivity And Binocular Summation After Lasik . Invest. Ophthalmol. Vis. Sci. 2004;45(13):199.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To analyze binocular function (binocular contrast–sensitivity function) and the role of interocular differences in corneal asphericity and corneal aberrations after laser in situ keratomileusis (LASIK). Methods: Binocular, both monocular CSF (contrast–sensitivity function) and interocular–differences in Q (asphericity) and corneal aberrations were measured pre– and post–surgery in 128 eyes of 64 patients. Binocular summation is calculated as the quotient of the binocular CSF divided by the average of the two monocular CSFs. The CSF test was conducted with the VCTS 6500 for spatial 1.5, 3, 6, 12 and 18 cpd. Corneal data were taken with an Eye–Sys 2000 topographer and corneal aberrations data were obtained from the VOL–3D programme. Results: Average binocular summation significantly diminishes (P=0.009) after LASIK for subjects with high interocular–differences in corneal asphericity (Q–difference>0.14) and aberrations. For these subjects (who also show high initial myopia), deterioration in binocular CSF data is higher than found for monocular CSF data. Subjects with low interocular–differences in corneal asphericity (Q–difference<0.14) and aberrations show a non–significant decrease (P=0.12) in binocular summation. Conclusions: The deterioration in binocular function for subjects with high interocular–differences in corneal asphericity and aberrations justify that the new proposals of ablation algorithms include criteria that improve binocular, and not just monocular, visual performance after refractive surgery. One simple practical criterion would be to minimize interocular–differences in Q after LASIK to values lower than 0.1.
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