Blue-Light Filtering Intraocular Implants and Darker Irises Reduce the Behavioral Effects of Higher-Order Ocular Aberrations

Abstract

Purpose

Higher order ocular aberrations (e.g. entopic scatter) arising from cornea and lens, decreases retinal image contrast by dispersing part of the image-forming optics over a broad retinal surface. Selective filtering of the light that is most susceptible to aberration (high-energy “blue” light) may reduce some of the behavioral effects. This was tested by comparing the performance of a blue-light filtering (BLF) vs a clear intraocular lens implant (IOL).

Methods

52 participants with IOL (BLF: AlconSN60AT; clear: AlconSA60AT; N = 98 test eyes; M = 67.33 $\pm \mathrm{ }$7.48 years; 58.8% Female; 25.5% non-White) were recruited. Our outcome measure was based on the minimum resolvable distance between two points of light (two-point thresholds), formed using broadband xenon or isolated short-wave energy (425 nm). Iris color was measured by visual inspection and comparison against standard images.

Results

In the broadband condition, patients with BLF IOL had smaller two-point thresholds (M = 17.17 ± 5.71 mm; F_[1,48] = 2.60; p = 0.045) than clear controls (M = 20.93 ± 10.22 mm). Similar improvements were found in the short-wave condition (M_BLF=17.02 ± 5.30; M_clear=21.42 ± 10.99; p = 0.04). In the contralateral broadband comparison, eyes with the BLF had significantly smaller two-point thresholds (M = 18.10 ± 10.47 mm; t = −2.90, p < 0.001) than the clear IOL (M = 20.89 ± 10.61 mm). Similar effects were seen in the short-wave condition (M_BLF=18.23 ± 9.88; M_clear = 21.06 ± 10.47; p = 0.001). Darker iris color was related to reduced scatter across IOL types, in both shortwave (F_[2,48] = 4.62, p = 0.02) and broadband (F_[2,48] = 5.27, p = 0.009) conditions.

Conclusions

Anterior screening, be it by a darker iris or a BLF IOL, is directly related to decreases in two-point light thresholds.

Keywords:

• Entoptic scatter
• blue-light filtering intraocular lens
• two-point thresholds
• iris color

Acknowledgements

The authors would like to thank Dr. Lauren Hacker at the Georgia Center for Sight in Athens, GA for her assistance in recruitment, and to Colin Gardner and Dr. Sarah Saint for their assistance in data collection.

Disclosure statement

Author BRH has received consulting fees from Alcon Laboratories. Author LRH is the spouse of author BRH and, thus, has the same conflict as author BRH.

Additional information

Funding

This work was supported by an investigator-initiated grant from Alcon Laboratories. The study design, conduct, analysis and interpretation were completed entirely by the authors, without input from the study sponsor.