Changes in circumpapillary retinal vessel density after acute primary angle closure episode via OCT angiography

Purpose To investigate the changes and evaluate the diagnosis value of circumpapillary vessel density (VD) in cases of acute primary angle closure (APAC). Design Case–control study. Methods APAC patients with a history of unilateral acute attack were enrolled. The eyes with acute episode constituted the case group while the contralateral eyes without attack consisted of the control group. Ophthalmic examinations including slit-lamp examination, best-corrected visual acuity, intraocular pressure and visual field were carried out. Retinal nerve fiber layer (RNFL), macular ganglion cell complex (GCC) were measured by spectral-domain optical coherence tomography, while VD was assessed by optical coherence tomography angiography. Results The whole en face image vessel density (wiVD), circumpapillary vessel density (cpVD) and inside disk VD for both all vessels and capillary were all significantly lower in the APAC eyes compared to the fellow eyes ( P < 0.01 for all). In APAC eyes, the wiVD, inside disk VD and cpVD both for all vessels and capillary were all positively correlated with RNFL and GCC thicknesses but negatively correlated with the mean deviation (MD), pattern standard deviation (PSD) and the duration of acute attack (all P < 0.01). From the ROC curve, the cpVD cap, wiVD cap , cpVD all and wiVD all all showed comparable diagnostic ability with RNFL, GCC and MD to differentiate eyes with APAC from the fellow eyes (all P > 0.05). The inside disk VD cap and VD all demonstrated significant lower diagnostic ability than the cpVD cap, wiVD cap , cpVD all and wiVD all (all P < 0.001). Conclusions In APAC eyes, circumpapillary VD decreased significantly compared with the fellow unaffected eyes. They were significantly correlated with thicknesses of RNFL and GCC, and visual field MD and PSD in the APAC eyes. The patients with longer duration of acute attack were more likely to have lower cpVD. For APAC, the diagnostic ability of wiVD and cpVD was similar with RNFL, GCC and MD and was higher than inside disk VD.