Vessel density and retinal nerve fibre layer thickness following acute primary angle closure.

BACKGROUND: To evaluate changes in circumpapillary vessel density (cpVD) and retinal nerve fibre layer (cpRNFL) thickness after a successfully treated episode of acute primary angle closure (APAC) and to identify factors associated with glaucoma progression in these eyes. METHODS: Twenty-six patients successfully treated for a unilateral episode of APAC were included in this prospective study. Optical coherence tomography (OCT) cpRNFL thickness and OCT angiography (OCTA) cpVD were compared between 2 and 8 months after treatment. Multiple logistic regression analysis was conducted to identify factors that influenced cpRNFL outcome. RESULTS: cpRNFL thicknesses was thinner in the affected eye (94.0 µm (95% CI: 87.3 to 100.8)) than in the unaffected fellow eye (103.1 µm (99.3 to 106.9)) at 2 months (p=0.039). The cpRNFL thickness of the affected eye decreased 8 months after remission (89.5 µm (84 to 95)), but was unchanged in the unaffected eye. Although cpVD was significantly lower (p=0.001) in APAC eyes 2 months after treatment (56.7% (53.8 to 59.7)) compared with fellow eyes (62.9% (61.4 to 64.4)), there was no significant change in cpVD of the affected eye between 2 and 8 months. In the multivariable analysis, the only factor that was associated with cpRNFL progression was lower cpVD at 2 months after APAC remission (OR=1.79, p=0.036). CONCLUSION: Early reductions of the vessel density and long-term decrease in cpRNFL thickness were observed during the first 8 months after an APAC attack. A lower vessel density at 2 months was the best predictor of conversion to an abnormal cpRNFL thickness. Glaucomatous progression should be suspected in eyes with lower vessel density even after remission of an episode of APAC.