Minor effect of blue-light filtering on multifocal electroretinograms

Purpose: To assess the impact of blue-light filtering on retinal processing to evaluate potential side effects of these filters on visual function at the neural level.

Setting: Department of Ophthalmology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.

Design: Cohort study.

Methods: Multifocal electroretinograms (ERGs) were recorded monocularly after pupil dilation in pseudophakic patients with a colorless intraocular lens (IOL) under 2 conditions: (1) stimulus perception through a yellow-tinted filter with the filter characteristics of the AF-1 YA-60BB IOL (blue-light filter) and (2) stimulus perception through a neutral filter that homogeneously attenuates the effective stimulus intensity like the blue-light filter independent of the wavelength. First-order kernel multifocal ERGs were extracted at 61 visual field locations and averaged for 5 stimulus eccentricities. Amplitudes and implicit times were determined for the multifocal ERG components N1 (first negative deflection), N2 (second negative deflection), and P1 (first positive deflection).

Results: The study evaluated 20 patients. Typical multifocal ERGs were obtained for both conditions at all eccentricities. There were no significant differences in amplitudes or implicit times between the 2 conditions except for a slight P1 amplitude enhancement (6.9%) with the blue-light filter at an intermediate eccentricity (P = .003).

Conclusions: The bipolar cell-dominated multifocal ERG was largely unaffected by short-term effects of blue-light filtering. The induced change in the spectral composition of the stimulus did not significantly alter the activity at the input stage of the visual system, specifically the retinal network comprising photoreceptors, horizontal cells, and bipolar cells.