Spherical Aberration Customization to Extend the Depth of Focus with a Clinical Adaptive Optics Visual Simulator

Journal of Refractive Surgery
Lucia Hervella, Eloy A. Villegas, Consuelo Robles, Pablo Artal

Purpose: To evaluate the use of the VAO adaptive optics visual simulator (Voptica SL, Murcia, Spain) for customization of spherical aberration to increase depth of focus.
Methods: Through-focus visual acuity with both high- and low-contrast letters from +1.00 to −3.00 diopters (D) was measured in 17 dilated eyes with three different induced amounts of spherical aberration for a 4.5-mm pupil diameter: control (0 µm), −0.15 µm, and −0.30 µm.
Results: The defocus curves followed the same behavior with both values of contrast, but the visual acuity was 0.2 logMAR lower with low contrast. The mean values of high-contrast logMAR visual acuity at far, intermediate (67 cm), and near (40 cm) were −0.10, 0.11, and 0.37 for control, 0.04, 0.00, and 0.15 for −0.15 µm, and 0.23, 0.00, and 0.06 for −0.30 µm conditions. The 95% confidence interval ranged from ±0.14 to ±0.45 logMAR and the middle 50% of the distribution was approximately 0.2 logMAR.
Conclusions: Negative values of spherical aberration extend the depth of focus in different ways depending on each patient. The VAO is a new instrument that allows the visual customization of spherical aberration to enhance depth of focus.