Assessment of Structural and Volumetric Choroidal and Retinal Indices in Eyes with Vogt-Koyanagi-Harada Disease
Muhammad Hassan, MD, Maria Soledad Ormaechea, MD, Sarakshi Mahajan, MD, Günay Uludağ, MD, Ariel Schlaen, MD, Quan Dong Nguyen, MD, MSc,
1. Byers Eye Institute, Stanford University, Palo Alto, CA, USA
2. Hospital Universitario Austral, Pilar, Buenos Aires, Argentina
Purpose: To compare retinal and choroidal indices among patients with stable Vogt-Koyanagi-Harada (VKH) disease without macular edema and post-resolution of the macular edema.
Methods: Patients with a confirmed diagnosis of stable VKH between 2009-2017 were divided into two groups based on the absence of macular edema (Group 1) and history of resolved macular edema (Group 2). SD-OCT (Heidelberg Spectralis®) was utilized to capture 5-line High Definition (HD) raster scan with Enhanced Depth Imaging. Semi-automated segmentation tool of Heyex Software Version 6.2 was utilized to segment the retinal layers into 1) Full Retina (FR); 2) Retinal Nerve Fiber Layer (RNFL); 3) Ganglion Cell Layer (GCL); 4) Inner Plexiform Layer (IPL); 5) Inner Nuclear Layer (INL); 6) Outer Plexiform Layer (OPL); 7) Outer Nuclear Layer (ONL); 8) Photoreceptor Layer (PRL); 9) Retinal Pigment Epithelium (RPE). A manual segmentation of choroid was also performed. Similar segmentation was performed on 22 normal eyes (11 patients).
Results: Forty-two eyes (22 patients) with VKH disease were analyzed. 32 eyes were in Group1 and 10 eyes in Group 2. Mean of average thickness and volume for the segmented layers were compared between the two groups and between the groups and controls (Table 1 and 2). The RNFL and INL layers were significantly thicker and voluminous while ONL and PRL were thinner with lower volume in Group 2 compared to other groups. Both study groups showed thickening and an increase in volume of OPL compared to normal eyes. The RPE layer was thickened with volumetric expansion in Group 1 but thinned out with a decrease in volume in Group 2. The mean central (1mm) choroidal thickness, average choroidal thickness, and choroidal volume were all significantly higher in group 1 compared to group 2 and controls. The choroidal indices were lower in group 2 compared to controls but failed to reach statistical significance.
Conclusions: VKH disease can exert significant effect on different retinal layers despite having minimal impact on the FRT. Furthermore, it has a pronounced effect on both choroidal thickness and volume. Macular edema is a very rare complication of VKH and the significant changes in choroid of patients with macular edema underscores the role of choroidal vasculature abnormalities as underlying pathogenesis.