Longitudinal Structural and Microvascular Imaging of Mouse Retina After Optic Nerve Crush Using Temporal Speckle-Averaging Visible Light OCT.

Purpose: To report high-resolution optical phenotyping of retinal structure and microvasculature after optic nerve crush (ONC) in the mouse using speckle-reduced visible light optical coherence tomography (Vis-OCT). Methods: Unilateral ONC was performed in 3-month-old wild-type mice (n = 13). In vivo Vis-OCT imaging was conducted on both injury and control eyes at baseline (before ONC) and 3 and 10 days post ONC. Volumetric averaging was applied to reduce speckle noise. The volume of nerve fiber bundles, retinal layer thicknesses, and trilaminar vessel densities in the superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP) were measured. Immunohistochemical analysis was done in the mice at day 10 to quantify the retinal ganglion cell density. Results: After ONC, retinal nerve fiber bundle volume increased by 28% at day 3 and decreased by 11% at day 10 relative to baseline (P < 0.01), corresponding with a 40% loss in retinal ganglion cell density. Ganglion cell complex thickness followed a similar trend, with an 8% increase at day 3 and a 13% decrease at day 10 (P < 0.01). The inner nuclear layer and the combined outer plexiform layer and outer nuclear layer exhibited persistent swelling at both day 3 and day 10. In contrast, vessel densities across the superficial vascular plexus, intermediate vascular plexus, and deep vascular plexus remained unchanged over the period of observation. Conclusions: Speckle-reduced Vis-OCT provides high-resolution, high-contrast, in vivo imaging that accurately captures retinal structural and microvascular changes following ONC in mice. Significant alterations in structure occur early, although microvascular changes were undetected in this ONC mice model.