Peripapillary Vessel Density and Retinal Nerve Fiber Layer Thickness in Patients with Unilateral Primary Angle Closure Glaucoma with Superior Hemifield Defect.

Nagalla Balakrishna,Tarannum Mansoori

doi:10.5005/jp-journals-10078-1247

Abstract

ABSTRACTPurposeTo 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 methodsThis 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.ResultsIn 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.ConclusionSector-wise RNFL thinning seems to precede the vascular changes and functional loss in the PAC and PACG eyes.How to cite this articleMansoori T, Balakrishna N. 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.

Highlights

Glaucoma is a multifactorial optic neuropathy characterized by a progressive retinal ganglion cell loss and glaucomatous visual field (VF) defect
radial peripapillary capillary (RPC) are the most superficial of the capillary layers, seen between the internal limiting membrane (ILM) and the retinal nerve fiber layer (RNFL).[6] Optical coherence tomography angiography (OCTA) imaging with RTVue-XR 100 Avanti OCT (AngioVue, AngioAnalytics, Optovue Inc., Fremont, CA) has a three-dimensional orthogonal registration algorithm called the split spectrum amplitude-decorrelation angiography (SSADA) for imaging and quantification of peripapillary RPC and optic nerve head (ONH) microcirculation.[5,7]Studies with OCTA have demonstrated reduced ONH and peripapillary vessel density (VD) in the patients with glaucoma.8–11Recent OCTA studies have reported a significant difference in the RNFL thickness and VD in the perimetrically intact regions of primary open-angle glaucoma (POAG) eyes, when compared to the normal eyes.[10–12]
In the primary angle-closure glaucoma (PACG) eyes with a inferior rim notch and corresponding RNFL defect (Figs 2A and 3A) and perimetrically affected superior regions (Fig. 2B), the RNFL thickness was reduced in IN, IT, and LT sectors (Table 2, Figs 2C and 3B) and there was a corresponding decrease in RPC VD (Table 2, Figs 2D and 3C) when compared with the primary angle-closure (PAC) eyes

Summary

Introduction

Glaucoma is a multifactorial optic neuropathy characterized by a progressive retinal ganglion cell loss and glaucomatous visual field (VF) defect. The study included 28 patients with unilateral PACG with the VF defect restricted to only superior hemisphere, 28 fellow eyes with PAC, and 30 control healthy eyes with the normal VFs on SAP. There was no significant difference among the age, gender, IOP at the time of scan, central corneal thickness, history of systemic hypertension, diabetes mellitus, and disc area between the PACG patients and normal controls (Table 1). All values are represented as: mean ±standard deviation *Chi-square test €Independent samples ttest

C: Normal control

Findings

Discussion