A comparison of the diagnostic ability of vessel density and structural measurements of optical coherence tomography in primary angle closure disease

Abstract

Purpose : To evaluate the vessel density measurements of the optic nerve head (ONH), peripapillary and macular regions on optical coherence tomography (OCT) angiography in eyes with primary angle closure disease (primary angle closure glaucoma, PACG eyes and PAC eyes with history of high intraocular pressure, IOP) and to compare their diagnostic abilities with that of the ONH rim area, peripapillary retinal nerve fiber layer (RNFL) thickness and the macular ganglion cell complex (GCC) thickness measurements on OCT.

Methods : In a cross sectional study, 77 eyes of 50 control subjects, 65 eyes of 45 PACG and 31 eyes of 22 PAC patients underwent vessel density and structural measurements with spectral domain OCT. Area under receiver operating characteristic curves (AUC) and sensitivities at fixed specificities of vessel densities in ONH, peripapillary and macular regions were compared with rim area, RNFL and GCC thickness.

Results : All the vessel density and structural measurements were significantly lower (p<0.05) in the PACG compared to the control group. Vessel densities in the PAC eyes were comparable (p>0.05) to that in the control eyes while the superotemporal RNFL thickness was significantly lesser in the PAC group (127 µm vs. 135 µm, p=0.01). The AUC and sensitivity at 95% specificity of vessel densities within the ONH (0.76 & 42%) and macular region (0.69 & 18%) in PACG were significantly lower (p<0.001) than ONH rim area (0.90 & 77%) and GCC thickness (0.91 & 55%) respectively. The same of peripapillary vessel density (0.85 & 53%) was comparable (p=0.25) to the RNFL thickness (0.91 & 65%).
AUCs of vessel density and structural measurements in differentiating PAC from control eyes were all less than 0.65.

Conclusions : Diagnostic abilities of OCTA vessel density measurements of the ONH and the macular regions in PACG were significantly lower than the ONH rim area and GCC thickness measurements, respectively, while that of peripapillary vessel densities were comparable to the RNFL thickness measurements. Vessel density measurements were comparable, while the superotemporal RNFL thickness was significantly lower in PAC compared to control eyes. This implies that the structural changes in PACD occur earlier than the vessel density reduction seen with OCTA.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.