Optical Coherence Tomography Study of Retinal Changes in Normal Aging and After Ischemia

PURPOSE. Age-related thinning of the retinal ganglion cell axons in the nerve fiber layer has been measured in humans using optical coherence tomography (OCT). In this study, we used OCT to measure inner retinal changes in 3-month-, 1-year-, and 2-year-old mice and after experimental anterior ischemic optic neuropathy (AION). METHODS. We used OCT to quantify retinal thickness in over 200 eyes at different ages before and after a photochemical thrombosis model of AION. The scans were manually or automatically segmented. RESULTS. In normal aging, there was 1.3-mu m thinning of the ganglion cell complex (GCC) between 3 months and 1 year (P < 0.0001) and no further thinning at 2 years. In studying age-related inner retinal changes, measurement of the GCC (circular scan) was superior to that of the total retinal thickness (posterior pole scan) despite the need for manual segmentation because it was not contaminated by outer retinal changes. Three weeks after AION, there was 8.9-mu m thinning of the GCC (circular scan; P < 0.0001), 50-mu m thinning of the optic disc (posterior pole scan; P < 0.0001), and 17-mu m thinning of the retina (posterior pole scan; P < 0.0001) in the 3-month-old group. Changes in the older eyes after AION were similar to those of the 3-month-old group. CONCLUSIONS. Optical coherence tomography imaging of a large number of eyes showed that, like humans, mice exhibited small, age-related inner retinal thinning. Measurement of the GCC was superior to total retinal thickness in quantifying age-related changes, and both circular and posterior pole scans were useful to track short-term changes after AION.