Ring-Based OCT Protocol for Retinal Ganglion Cell Complex Thickness Analysis in Mice

Optical coherence tomography (OCT) enables non-invasive, high-resolution imaging of retinal layers and is widely used to assess structural changes in preclinical models of retinal and optic nerve disease. However, OCT-based retinal thickness measurements in rodents remain insufficiently standardized, with differences in measurement location and segmentation methodology potentially limiting reproducibility and comparability across studies. We describe a standardized OCT-based protocol for ganglion cell complex (GCC) thickness measurement in mice using predefined retinal landmarks and manual segmentation. Six radial OCT scans separated by 30° are acquired around the optic nerve head, and GCC thickness is measured using ImageJ at three nominal radial distances on each side of the optic nerve: 1000, 1500, and 2000 μm. The applicability of the protocol was evaluated in a murine optic nerve crush (ONC) model. GCC thickness decreased significantly over time, from 68.8 ± 5.2 μm at baseline to 60.7 ± 8.0 μm at day 15 and 60.6 ± 9.8 μm at day 24. Radius- and quadrant-specific analyses further demonstrated the ability of the protocol to detect regional patterns of GCC thinning. This protocol provides a structured approach for OCT-based GCC thickness assessment in mice and may improve consistency and comparability across preclinical studies.