Optical Coherence Tomography Biomarkers in Acute Vogt-Koyanagi-Harada Disease: Clinical Significance of Hyperreflective Outer Nuclear Layer and Bacillary Layer Detachment.

Purpose: To assess the clinical importance of hyperreflective outer nuclear layer (HONL) and bacillary layer detachment (BALAD) on optical coherence tomography in acute Vogt-Koyanagi-Harada (VKH) disease.

Methods: A retrospective analysis of 24 patients with acute VKH, involving at least 12 months of follow-up.

Results: Among the 42 eyes with serous retinal detachment (SRD) at presentation, BALAD was identified in 21 eyes (50%) and HONL in 23 eyes (55%). Eyes with BALAD and HONL had poorer median best corrected visual acuity (BCVA) at baseline (p = 0.023, p = 0.002), but the final BCVA showed no difference between groups (p = 0.965, p = 0.287). The height of SRD at presentation was greater in eyes with BALAD and HONL than those without (p = 0.026, p < 0.001).HONL was strongly associated with SRD height (p < 0.001). The rates of loss of ellipsoid zone (EZ) and retinal pigment epithelium (RPE) integrity were higher in eyes with BALAD at 1 month (p < 0.05), although no significant difference was noted at 1 year (p = 0.520). In the HONL group, EZ and RPE integrity loss rates were higher at 1 month and 1 year (p < 0.05). Subfoveal choroidal thickness values did not vary based on the presence of HONL or BALAD at 1 month, 1 year, and during the last visit after treatment (p > 0.05). Ocular complication and recurrence rates were comparable across all groups (p > 0.05). HONL and BALAD were not considered significant risk factors for recurrence (p > 0.05).

Conclusion: In patients with acute VKH, HONL and BALAD were associated with more severe clinical features at presentation. However, HONL and BALAD did not affect long-term visual prognosis, recurrence, and development of ocular complications.