Purpose
To describe change in visual acuity by morphological responder status in the “alternative treatments to Inhibit VEGF in Age-related choroidal Neovascularisation (IVAN) clinical trial which compared two drugs ranibizumab versus bevacizumab and two treatment regimens namely monthly or as needed (discontinuous).
Methods
We computed the change in metric of total retinal thickness (TRT) measured on the optical coherence tomogram from baseline to 12 months and classified our participants into 3 morphological responder categories. Of the 509 eyes included in this analysis, reductions in TRT in the 75th percentile or greater were classified as responders (n = 126), those with changes in the 25th percentile or less as non responders (n = 128) and the rest as intermediate responders (n = 255). Plots of change in best corrected visual acuity (BCVA) for each of the responder groups by continuous or discontinuous treatment status were generated.
Results
At M3, the mean change in TRT was most marked in the responder group and flat in the non responder group, with intermediate responders achieving around 33% of the reduction in TRT seen in the responder group (Figure). Beyond M3, responders and intermediate responder groups showed no significant change, but TRT in non responders rose marginally. BCVA improved in all groups but was highest in responders. At M12 mean(SD) change in BCVA was 6.0 (13.2), 6.1 (12.3) and 3.0 (12.3) in responder, intermediate and non responders respectively . On comparing BCVA outcomes by continuous or discontinuously administered treatment, smaller improvements were seen with the latter but only in intermediate and non responder groups and did not reach statistical significance (non responders p = 0.26, intermediate p = 0.18,responders p = 0.14).
Conclusions
Despite absence of responsiveness to antiVEGF therapy on the metric of TRT, improvements in BCVA are seen in treated eyes. BCVA outcomes tended to be similar within morphological responder groups regardless of whether treatment was given every month or discontinuously . Tomographic morphological changes are only weakly associated with functional improvement as measured by BCVA.
Keywords: 412 age-related macular degeneration •
748 vascular endothelial growth factor •
754 visual acuity