Evaluation of Visual Quality Following Monovision Correction by LASIK in Presbyopic Patients
In the following cohort study, researchers in Spain sought to evaluate visual quality after laser in situ keratomileusis (LASIK) performed to achieve monovision in presbyopic patients.
They performed LASIK with the Allegretto Wave Eye-Q 400 Hz laser and corrected the dominant eye for far vision and the nondominant eye for near vision by targeting –1.25D of myopia. The researchers programmed the F-CAT algorithm targeting a postsurgical corneal asphericity of –0.80 in the dominant eye and –1.00 in the nondominant eye and analyzed visual acuity, contrast sensitivity function, ocular aberrations, stereoacuity, the scattering index and the visual discrimination capacity preoperatively and 3 months postoperatively.
The study researchers enrolled 25 patients (50 eyes) with a mean age of 49.3 years ± 4.5 (SD). They found that postoperatively, more than 90% of patients had a binocular uncorrected distance and near visual acuity of 0.0 logMAR or better, although the contrast sensitivity function diminished, especially in the nondominant eye and with binocular vision. They noted that stereoacuity was significantly worse in all patients (p<.001) and that the visual discrimination capacity declined in nondominant eyes and under binocular conditions (p<.005); no significant changes occurred in dominant eyes (p=.614). Moreover, in all eyes, the mean objective scatter index value increased postoperatively, but not significantly (p>.05).
The researchers found that monovision correction by LASIK improved functional near vision in presbyopic patients. They found that although visual acuity was good for far vision, contrast sensitivity and stereoacuity diminished significantly.
SOURCE: Alarcón A, Anera RG, Villa C, et al. Visual quality after monovision correction by laser in situ keratomileusis in presbyopic patients. J Cataract Refract Surg. 2011;July 13