Dose-dependent retinal damage in a LED white bright light model

Abstract

Purpose : The current study was performed to evaluateevaluate the feasibility to design a white bright light damage system using more efficient LEDs capable of inducing photoreceptor degeneration in a dose dependent manner.

Methods : Retinal damage was induced in 6-8 weeks old male Balb/c mice (Janvier Labs) at naïve, 30% (low), 60% (mid), or 100 % (high) for 30 min. White light damage was induced in a custom system using warm white LED strips (RGB+CCT 24 V CRI 98).
The retinal layers were measured in vivo by spectral domain optical coherence tomography (SD-OCT. Envisu R2200. Bioptigen/Leica Microsystems). Retinal thickness was analyzed using a proprietary convolutional neuronal network. The retinal function was evaluated by scotopic flash electroretinography (flash ERG. Celeris. Diagnosys LLC). Amplitude and latency of the a and b waves were manually analyzed. At the end point, animals were euthanized, and eyes were enucleated for histology/immunohistological analysis (to be available). Measurements were performed at at baseline and Day 7 after induction.
The data were graphed and statistically analyzed using the GraphPad Prism software (GraphPad Software). Data were analyzed by Two-way Repeated Measures Anova followed by Holm-Šídák’s multiple comparison test. Differences were considered significant at the P < 0.05 level.

Results : The outer retina appeared to suffer the highest degree of damage. With the outer plexiform layer (a decrease of 6% for the low, 44% for the mid and 50% for the high vs the Naïve) and inner segment (4%, 28% and 31%) showing significant light intensity dose-dependent changes (P<0.01). Similar changes were seen superior and inferior regions.
The photoreceptor a-wave amplitude significantly decreased in an intensity dose dependent manner in the iduced groups. At the 3 cd.s/m2, the amplitude decreased 6% in the low, 40% in the mid and 47% in the high intensity groups vs. the Naïve. The decrease in the retina functional outcomes presented a strong correlation with the outer retina layer thickness for the mid and high groups.

Conclusions : The designed system was capable of inducing retinal damage, focused on the photoreceptor layers, in a light intensity dependent manner. The adjustable system will allow for more customization of damage for the evaluation of test articles targeting dry age-macular degeneration

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.