Title : Evaluating electroretinogram responses to pan-retinal laser photocoagulation from different retinal pigmentations
Abstract:
Background: Pan-retinal laser photocoagulation (PRP) is used in the management of diabetic retinopathy, aimed at preventing the growth of abnormal blood vessels in the retina and reducing the risk of vision loss. Absorption of laser occurs from pigment cells within the retina, which vary between individuals. The impact of these pigmentation differences on retinal function changes following PRP is not understood. The RETeval device provides a means of assessing the retina's electrophysiological response to flashes of light, producing a waveform which reflects the activity of different retinal cell layers, offering insights into retinal function.
Methods: Twelve participants receiving PRP were recruited from the University Hospitals of Leicester Argon Laser clinic following mydriasis. Electroretinograms (ERGs) were recorded using RETeval, with three different protocols: Flicker 16 Td-s, Flicker 32 Td-s, and ISCEV Photopic Flash/Flicker Td-s, both before and after laser treatment. Fundus photographs were taken to quantify retinal pigmentation using red-green-blue (RGB) colour analysis, with ERG implicit times and amplitudes compared before and after laser, and between different pigmentation groups.
Results: Amplitudes in all protocols significantly decreased following PRP across all participants (p< 0.05). RGB analysis identified a cut-off score of 64 to differentiate between low and high retinal pigmentations. The ISCEV Photopic Flash/Flicker Td-s protocol revealed that a-wave amplitudes were significantly lower in participants in the high retinal pigmentation group after PRP, than the low retinal pigmentation group (p< 0.05).
Conclusion: PRP leads to an immediate reduction in retinal function. Retinas with higher pigmentation have a greater retinal function impairment following PRP, suggesting increased laser absorption, and highlighting the need for tailored treatment approaches to minimise these disparities. The chosen RETeval protocols provided quick and reliable assessments of retinal function within ophthalmology clinics, with the potential for its use of the device in patient groups that cannot comply with table-mounted tests.
