Choroidal Vascularity Index among Filipinos with Non-Neovascular and Neovascular Age-Related Macular Degeneration using Binarization of Enhanced Depth Imaging Optical Coherence Tomography

Objective: This study compared the choroidal vascularity indices (CVI) among eyes with neovascular, nonneovascular age-related macular degeneration (AMD) and healthy controls. Methods: Spectral-domain optical coherence tomography (OCT) with enhanced depth imaging (EDI) from 52 eyes of 33 subjects were analyzed and designated into 3 groups: control, non-neovascular AMD, and neovascular AMD. Using Image J software, a 1.5 mm subfoveal choroidal area was segmented and binarized to measure total and luminal choroidal areas. The CVI was calculated as the ratio of luminal to total choroidal area. Correlation studies were done to assess relationship of CVI with best-corrected visual acuity (BCVA) and disease severity. Results: The overall median CVI was 0.66 (IQR = 0.62 – 0.69), with overall median total choroidal area of 696,707.60 (IQR = 530,776.80 – 806,348.00), overall median luminal choroidal area of 442,884.60 (IQR = 351,612.80 – 549,540.30), and an overall median choroidal thickness of 237.10 (IQR = 178.43 – 270.25). The overall median LogMAR BCVA was 0.30 (IQR = 0.10 – 0.54). Statistical comparisons showed no significant differences in the median CVI, median total choroidal area, median luminal choroidal area, and median choroidal thickness among the three groups (p>0.05). However, median BCVA was significantly different among the groups (χ2=35.98, p=0.001). Specifically, those with non-neovascular AMD and neovascular AMD had significantly worse visual acuity compared to the control group (p<0.05). Conclusion: The study found that CVI, as measured by binarization of EDI-OCT images, was not significantly different among AMD and control groups. BCVA, however, was significantly affected by AMD. These findings suggest that while CVI may not vary with AMD severity, BCVA remains a crucial diagnostic factor. Further research is needed to explore the relationship between choroidal vascularity and AMD using advanced imaging techniques.