Peripapillary Vessel Density and Retinal Nerve Fiber Layer Thickness in Patients with Unilateral Primary Angle Closure Glaucoma with Superior Hemifield Defect
OCT angiography, Primary angle-closure, Primary angle-closure glaucoma, Retinal nerve fiber layer thickness, RPC vessel density, Superior hemifield loss
Citation Information :
Peripapillary Vessel Density and Retinal Nerve Fiber Layer Thickness in Patients with Unilateral Primary Angle Closure Glaucoma with Superior Hemifield Defect. J Curr Glaucoma Pract 2019; 13 (1):21-27.
Purpose: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness and radial peripapillary capillary (RPC) vessel density (VD) in the eyes with unilateral primary angle-closure glaucoma (PACG) with the visual field (VF) defect confined to the superior hemifield and compare these parameters with the corresponding perimetrically intact regions of the fellow eye with primary angle-closure (PAC) and normal control eyes, using optical coherence tomography angiography (OCTA).
Materials and methods: This prospective, cross-sectional study included 28 eyes with unilateral PACG, with VF defects restricted to the superior hemifield, 28 fellow eyes with PAC, and 30 age-matched normal controls. Peripapillary RNFL thickness and RPC VD were measured in the eight peripapillary sectors, using OCTA, and these parameters were compared among the corresponding sectors of PACG, PAC, and healthy eyes using analysis of variance (ANOVA) with the Bonferroni post hoc analysis.
Results: In PACG eyes, there was a significant difference in the RNFL thickness (p < 0.0001) and RPC VD (p = 0.001) between the superior and the inferior hemifield. In PAC and normal eyes, there was no significant difference in the RNFL thickness and RPC VD between the superior and the inferior hemifield. Within the perimetrically intact regions of the PACG eyes, the mean RNFL thickness was significantly reduced in the superonasal (SN) and upper nasal (UN) sectors (p = 0.02), but the VD did not show any significant difference, when compared to the fellow PAC eyes. In PACG eyes, the mean RNFL thickness was significantly reduced in the perimetrically normal SN and UN sectors (p < 0.0001) and the VD was reduced in the UN sector (p = 0.01), when compared to the normal eyes. When comparing the peripapillary sectors of the PAC and healthy eyes, RNFL thickness was reduced in UN (p = 0.02), lower nasal (LN) (p = 0.01), inferonasal (IN) (p = 0.02), and inferotemporal (IT) sectors (p = 0.03) and there was no significant difference in the VD in any of the sectors. Inside disc capillaries were preserved in all the three groups.
Conclusion: Sector-wise RNFL thinning seems to precede the vascular changes and functional loss in the PAC and PACG eyes.
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