Clinical characteristics of choroidal microvasculature dropout in normal-tension glaucoma versus nonarteritic anterior ischemic optic neuropathy: an optical coherence tomography angiography study

The present study investigated the characteristics of choroidal microvasculature dropout (CMvD) in eyes with nonarteritic anterior ischemic optic neuropathy (NAION) versus those in eyes with normal-tension glaucoma (NTG). This study included 27 NAION, 27 NTG, and 27 healthy control subjects. CMvD was observed in 15 eyes (55.6%) of the NAION group and 20 (74.1%) of the NTG group. The area and angular width of CMvD were significantly greater in eyes with NAION (0.278 +/- 0.172 mm(2) and 86.5 +/- 42.3 degrees) than in those with NTG (0.138 +/- 0.068 mm(2) and 35.1 +/- 16.2 degrees, p = 0.002 and p < 0.001, respectively). CMvD in eyes with NAION were distributed in 120-250 degrees and most frequently located at the temporal region, while CMvD in eyes with NTG showed double peaks at 220-280 degrees and 110-140 degrees and most frequently located at the inferotemporal region. The factors associated with the discrimination of NAION from NTG were greater area of CMvD (OR, 1.181; 95% CI, 1.021-1.366; p = 0.025) and location closer to the temporal region of the CMvD (OR, 0.904; 95% CI, 0.838-0.975; p = 0.009). The clinical characteristics of CMvD differed between eyes with NAION and those with NTG. Optical coherence tomography angiography may provide an additional approach to differentiating glaucoma from NAION.

Automated summary

This study compared the characteristics of choroidal microvasculature dropout (CMvD) in eyes with nonarteritic anterior ischemic optic neuropathy (NAION) and normal-tension glaucoma (NTG). The area and angular width of CMvD were significantly larger in NAION eyes, mainly located in the temporal region, while NTG eyes showed a different distribution pattern. Factors distinguishing NAION from NTG included larger CMvD area and closer proximity to the temporal region. Optical coherence tomography angiography could be a helpful tool in differentiating these two conditions.