Optical Density Analysis of Subretinal Fluid in Vogt Koyanagi Harada Disease, Posterior Scleritis and Acute Central Serous Chorioretinopathy

To assess the diagnostic/prognostic utility of the Optical Density (OD) from subretinal fluid (SRF) analyses across Vogt-Koyanagi-Harada disease (VKH), posterior scleritis (PS) and acute central serous chorioretinopathy (CSCR). This study was conducted in treatment-naive patients with VKH, PS and CSCR presented with SRF. Optical coherence tomography (OCT) images were analysed using ImageJ. OD ratios (ODR) were calculated as the ratio of OD of SRF to OD of vitreous (ODR1-2), retinal pigment epithelium (ODR3) and retinal nerve fibre layer (ODR4). Associations between demographics, ocular findings, OCT findings, best corrected visual acuity (BCVA) change and OD were analysed. The study comprised 64 patients/81 eyes. ODR1 and ODR2 were found significantly higher in CSCR than VKH (p = 0.004 and 0.031). ODR4 showed significantly higher in PS than VKH (p = 0.013). With an increase in the anterior chamber reaction, there was a significant increase in OD of SRF and ODR3 in the PS (p = 0.034 and 0.016). BCVA showed a significant improvement in all groups at 12-month follow-up (p < 0.05). In the VKH, the OD of vitreous and ODR3 positively correlated with baseline BCVA (p = 0.006 and < 0.001) and ODR4 with 12th-month BCVA (p = 0.03). This study demonstrates that OD has the potential to serve as a non-invasive, objective, and easily interpretable method for differentiating between VKH, PS, and CSCR. The OD can be used as a valuable method for prognostic evaluation in relation to visual acuity outcomes, especially in the VKH group.