Figure 2. Chronic unpredictable mild stress (CUMS) induced retinal nerve fiber layer (RNFL) thinning without intraocular pressure (IOP) elevation. A: IOP was measured weekly. The IOP of both groups of mice fluctuated slightly. No significant elevation of IOP was observed during the 5-week experiment. B: The RNFL thickness was determined at the end of 5 weeks of CUMS exposure. We observed a significant reduction in RNFL thickness via optical coherence tomography (OCT) measurement. Data are presented as mean ± standard error of the mean (SEM), n = 9–12. **p<0.01, ***p<0.005.