Purpose: To evaluate whether the status of the external limiting membrane (ELM) or inner segment/outer segment junction (IS/OS) improves after intravitreal injection of ranibizumab for age-related macular degeneration (AMD). We also evaluated whether the pre-operative values of these parameters are associated with the visual prognosis.
Methods: This was a hospital-based, cross-sectional study. Seventy-six eyes of 76 treatment-naive AMD patients who received three monthly intravitreal injections of ranibizumab followed for more than 6 months with additional as-needed injections were investigated. Spectral domain OCT was used to evaluate the length of ELM, IS/OS, and foveal thickness pre- and post-operatively. Changes of ELM and IS/OS length were evaluated postoperatively. Correlation coefficients between pre-operative parameters and post-operative visual acuity were also analyzed.
Results: Significant changes were noted in mean logMAR (0.66 to 0.53), foveal thickness (231.1 to 151.1 μm), and IS/OS length (514.9 to 832.3 μm) after the treatment. ELM length did not improve significantly (1,312.4 to 1,376.7 μm). Restoration of IS/OS occurred where ELM is retained. Although pre-operative ELM length, IS/OS length, and foveal thickness showed correlation with post-operative logMAR (R = -0.51, -0.39, and 0.46, respectively), the most powerful predictive factor for visual prognosis was pre-operative logMAR (R = 0.77, p < 0.001).
Conclusions: IS/OS status improves in response to anti-VEGF therapy but ELM seems to have less plasticity. The status of IS/OS and ELM can be used as prognostic factors but the predictive power is inferior to that of baseline visual acuity.