Use of the multifocal electroretinogram (mfERG) for assessing the response of 670 nm light emitting diodes (LED) photoillumination in an animal model with laser retinal injuries.

There is no uniformly accepted objective method to diagnose the functional extent of retinal damage following laser eye injury and there is no uniform therapy for laser retinal injury. J.T. Eells, et al, (1) reported the use of Light Emitting Diodes (LED) photoillumination (670 mn) for methanol-induced retinal toxicity in rats. The findings indicated a preservation of retinal architecture, as determined by histopathology and a partial functional recovery of photoreceptors, as determined by electroretinogram (ERG), in the LED exposed methanol-intoxicated rats. The purpose of this study is to use multifocal electroretinography (mfERG) to evaluate recovery of retinal function following treatment with LED photoillumination in a cynomolgus monkey laser retinal injury model. Control and LED array (670 nm) illuminated animals received macular Argon laser lesions (514 mn, 130 mW, 100 ms). LED array exposure was accomplished for 4 days for a total dose of 4 J/cm(2) per day. Baseline and post-laser exposure mfERGs were performed. mfERG results for five animals post-laser injury but prior to treatment (Day 0) showed increased implicit times and P1 waveform amplitudes when compared to a combined laboratory normal and each animal's baseline normal values. In general, preliminary mfERG results of our first five subjects recorded using both the 103-hexagon and 509-hexagon patterns indicate a more rapid functional recovery in the LED illuminated animal as compared to the control by the end of the fourth day post-exposure. Research is continuing to determine if this difference in functional return is seen in additional subjects and if statistical significance exists.