Abstract
Purpose :
This study investigates through-focus behavior of halo and glare of real intraocular lenses (IOLs) as perceived by observers in a see-through system. The purpose of this work is to get insight on how residual refractive errors can influence visual symptoms from different IOL technologies.
Methods :
Measurements were performed using the novel see-through system IOL Telescope Type 2 (IOL-T2) described earlier (Lundström L. et al., ARVO 2022). This system ensures 1:1 transfer of scattering from IOL plane into the physical pupil plane of the observer. In this study, the IOL-T2 without the IOL inside has negligible spherical aberration (SA).
Halos and glare were assessed with a “inner and outer ring test”, presented earlier (Jenkins M.D. et al., ARVO 2022). The protocol included 3 rings with luminance 52, 23 and 8 cd/m2 respectively.
The observers were looking through the IOL-T2 at on-axis glare source on a dark screen, 3 m away from the eye. The glare source was a white LED with a 1.5 mm aperture, set to luminance 537 cd/m2. The screen was a white diffusive foam board. The ring test was imaged on the screen with a projector.
In this study 4 aspheric IOLs of +20.0 D were tested: monofocal, enhanced monofocal, diffractive extended depth of focus (EDOF) and refractive EDOF. All tested lenses have negative SA. Therefore, when loaded into the IOl-T2, combined SA of the whole system is negative.
The ring test was performed for [-1; +1] D defocus range in 0.5 D steps. Experiments were done on 4 healthy subjects with cycloplegia, the pupil was restricted by a 4 mm physical aperture in the IOL plane.
Results :
For all 3 rings, the through-focus ring sizes of diffractive EDOF IOL are larger compared to both monofocals and the refractive EDOF for the whole defocus range. Additionally, the ring size curves for refractive EDOF and monofocal IOLs are flatter than for diffractive EDOF IOL. All IOLs show asymmetric through-focus ring sizes behavior for positive and negative defocus, most likely due to spherical aberration of the setup.
Conclusions :
In this study through-focus behavior of the IOL-induced visual symptoms was evaluated using the novel IOL-T2. Results show that refractive EDOF IOL behaves in the same way as the monofocal models in the whole tested defocus range. The curves also suggest that visual symptoms of the refractive EDOF IOL have similar dependence on residual defocus as compared to both monofocal models.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.