Identification of optical density ratios in subretinal fluid as a clinically relevant biomarker in exudative macular disease

PURPOSE: To investigate the potential role of optical density ratios (ODRs) obtained from subretinal fluid analysis in exudative macular disease and to identify the predictive role of ODRs under therapy in comparison to conventional morphometric measurements (CMMs). METHODS: Fifteen patients with neovascular age-related macular degeneration (nAMD) and 15 with acute central serous chorioretinopathy (CSC) were included in this prospective comparative and interventional case series. High-definition optical coherence tomography (SD-OCT) was performed according to a standardized protocol. nAMD patients received a standard treatment consisting of three monthly doses of intravitreous ranibizumab. Best corrected visual acuity (BCVA) was assessed at baseline (BSL) and weeks 2, 4, and 12. SD-OCT parameters were compared between CSC and nAMD at baseline. Predictive factors for functional recovery under ranibizumab treatment were identified in patients with nAMD. RESULTS: ODR showed highly significant differences between CSC and nAMD, whereas it was not possible to differentiate between these diseases on the basis of CMM. During follow-up, CMM correlated with BCVA at BSL only, whereas ODR showed a significant correlation with BCVA at week 4 and 12 during antiangiogenic therapy. CONCLUSIONS: Results suggest that CMM may correlate with BCVA at BSL, but has limited predictive value regarding recovery of visual function. Most interesting, ODR correlated with BCVA under therapy and was the only parameter that was pathognomic for nAMD in contrast to CSC in this study. ODR may reflect the status of the blood-retina barrier and may be used for pathophysiologic differentiation and prognostic purposes in exudative macular disease.