Bacillary Layer Detachment in Acute Vogt-Koyanagi-Harada Disease.

Objectives: To evaluate the frequency and treatment response of eyes with bacillary layer detachment (BLD) in acute Vogt-Koyanagi-Harada (VKH) disease using spectral-domain optical coherence tomography (SD-OCT). Materials and Methods: We retrospectively reviewed the medical records of 58 eyes of acute VKH patients with at least 6 months of follow-up between January 2009 and March 2021. SD-OCT, color fundus photographs, and fluorescein angiography images were analyzed in all patients. Results: The study included 58 eyes of 29 patients. BLD was detected in 33 of the 58 eyes (56.9%) at baseline. Mean serous retinal detachment (SRD) height was 918.50±336.64 μm in the BLD group and 215.33±167.83 μm in the group without BLD (p<0.05). A positive correlation was found between SRD height and the presence of BLD (r=0.783, p<0.05). BLD was significantly more common in patients with a baseline SRD height greater than 500 μm (p<0.05). As subfoveal central choroidal thickness (CCT) could not be measured by enhanced depth imaging-OCT at baseline due to extreme choroidal thickness in all eyes, the earliest post-treatment CCT measurements were analyzed. At the completion of pulse steroid therapy, mean CCT was 425±82.87 μm in the BLD group and 385.58±82.87 μm in the group without BLD (p=0.04). The mean time to BLD resolution was 12.88±6.5 days (range: 2-26). Conclusion: BLD is a common tomographic finding in eyes with acute VKH disease and can be differentiated from the associated SRD through careful SD-OCT analysis. Though it is mostly observed in patients with more serious disease, the presence of BLD has no negative effect on long-term visual function.