Evaluating The Protective Effect Of A Yellow Filter In The Rodent Model Of Light-induced Retinopathy (LIR)

Abstract

Purpose: : There are indications that compared to clear intraocular lenses (IOL), yellow IOL may protect the retina from the deleterious effects of light by blocking the "blue" light. We assessed this with our rodent model of LIR.

Methods: : Adult (n=20) and newborn (n=12) mice were exposed (adults: 6 consecutive days; neonates: between postnatal days 14-28) to a bright luminous environment of 2500 lux within clear Plexiglas cages covered (YL) or not (BL) with a Roscolux #98 yellow filter (i.e. the same spectral characteristics as commercially available "yellow" IOL’s). The efficacy of the yellow filter was evaluated with the electroretinogram (ERG) at 1 and 7 days post exposure.

Results: : (Adult mice): On day 1, both groups yielded amplitude measurements that were significantly reduced (p<.05) compared to normal values. Of interest, the photopic ERGs of the YL group was the largest (70± 21µvolts vs 85± 24µvolts); a difference that was, however, no longer measurable by day 7. (Neonate mice): Photopic (normal: 72± 10µvolts, BL: 43± 14µvolts, YL: 60± 10µvolts) and scotopic (normal: 676± 113µvolts; BL: 289± 43µvolts, YL: 330± 28µvolt) ERGs were significantly (p<.05) reduced in amplitude following bright light exposure. However, while there were no significant differences in scotopic amplitudes between the BL and YL groups (p>.05), photopic ERGs were significantly larger in the YL group (p<.05).

Conclusions: : We have previously shown that in our model of LIR, the scotopic ERG is affected earlier and significantly more compared to the cone ERG. Blocking the blue light contribution to the bright luminous environment did not prevent damage to the rod-driven ERG but appeared to have successfully protected the cone mediated ERG; the latter effect being most pronounced in our neonate LIR model. It remains to be determined however if this protective effect is permanent or transient as suggested from our adult mice model. Supported by NSERC and Réseau Vision.

Keywords: electroretinography: clinical • electroretinography: non-clinical • age-related macular degeneration