Computational evaluation of a novel intraocular lens design for controlling negative peripheral pseudophakic dysphotopsia

Abstract

Purpose : Pseudophakic individuals experiencing negative peripheral dysphotopsia (DYS) report a persistent ‘shadow’ in their far peripheral visual field. The optical basis of DYS has been identified previously.¹ While some designs have been evaluated², no IOL designed specifically for controlling DYS are currently clinically available. In this study, the efficacy of a novel IOL design for controlling DYS is evaluated through computational modelling.

Methods : A 3D model of a pseudophakic eye based on the Escudero-Navarro Eye Model² was constructed (Figure 1). For control evaluation, an equiconvex intraocular lens (+22 D power, refractive index 1.55, 6 mm optic diameter) was placed in the model. Non-sequential optical ray-tracing using OpticStudio (Zemax, Kirkland WA) was conducted with incident light angle ranging from 55° to 100° in 0.5° steps. At each incident angle, 10,000 randomly distributed parallel rays were traced through the model. Using an analysis method based on Simpson (2019)³, the relative retina intensity distribution (RID) was computed from the range of incident angles. The analysis was repeated for all combinations of pupil diameters (PD) from 2.0 mm to 5.0 mm in 0.5 mm steps, and lens axial positions (LAP) from 0.0 mm to 1.0 mm in 0.1 mm steps. The evaluation process was repeated for an IOL comprising the same central optical zone parameters but enhanced with novel peripheral surface contours described using cubic Bezier curves for preventing DYS.

Results : For the control lens, discrete combinations of PD and LAP resulted in illumination gaps in the RID (e.g. Figure 2a), indicating potential presence of DYS. An interplay between PD and LAP was evident leading to DYS at various PD over different LAP (and vice versa). For the novel lens design, RID results show no illumination gaps at any combinations of PD and LAP (e.g. Figure 2b).

Conclusions : The novel IOL design appears to be effective in controlling DYS over a range of PD and LAP. The seemingly quasi-random clinical presentation of DYS may be partially explained by the interplay of PD and LAP on the formation of retina illumination gaps.

References
1. Holladay & Simpson 2017 JCRS
2. Escudero-Sanz & Navarro 1999 JOSA
3. Erie et al 2019 JCRS
4. Simpson 2019 JOSA

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.