Acute ocular hypertension diminishes flicker-induced enhancement in retinal blood flow and full-field electroretinogram in a mouse model

Abstract

Purpose: Transient flickering light stimulation (FLS) was previously demonstrated to enhance both retinal blood flow (RBF) and full-field electroretinogram (ffERG) responses in wild-type mice. This study aimed to investigate the effects of acute ocular hypertension (AOH) on these flicker-induced changes in mice. Methods: Adult C57BL6J mice were randomly divided into three groups: the AOH, sham, and naïve groups. All animals underwent the following measurements, including scotopic and photopic ffERGs (pre- and post-12 hertz [Hz] FLS), optical coherence tomography (OCT), and Doppler OCT (pre- and post-12 Hz FLS), at baseline (day 0), day 16, and day 43. On day 8, intraocular pressure (IOP) was elevated to 80 millimeters of mercury (mm Hg) in the AOH group or maintained at 15 mm Hg in the sham group for 1 hour. The naïve group received no intervention. Results: Transient FLS significantly enhanced both RBF and photopic b-wave amplitudes in all three groups at day 0 (baseline). The AOH group showed significant reductions in the positive scotopic threshold responses and both inner and middle retinal layer thicknesses at days 16 and 43. Significant flicker-induced increases in RBF and b-wave amplitudes were observed in the sham and naïve groups at days 16 and 43. However, significant reductions in flicker-induced enhancements of RBF and b-wave amplitude were observed in the AOH group at days 16 and 43 compared with the sham and naïve groups. Conclusions: Flicker-induced enhancements in RBF and electro-retinal responses were impaired by AOH. This impairment suggests that the retinal functional hyperemia is sensitive to IOP elevation.