Steeper structure-function relationship in eyes with than without a parapapillary deep-layer microvasculature dropout

Ji-Ah Kim,Hyunjoong Kim,Eun Ji Lee,Tae-Woo Kim

doi:10.1038/s41598-018-32499-8

Abstract

The degree of visual field (VF) loss can vary widely at a given level of retinal nerve fiber layer (RNFL) thickness. The cause of this variability is not fully understood. This cross-sectional study investigated whether the presence of choroidal microvasculature dropout (MvD) influences on the structure-function relationship among glaucomatous eyes. Seventy-one primary open-angle glaucoma (POAG) patients with choroidal MvD as determined by optical coherence tomography angiography (MvD+ group), and 71 age- and inferotemporal (IT) RNFL thickness-matched POAG patients without MvD (MvD– group) were included. VF sensitivity within the region corresponding to the IT RNFL sector was averaged using the total and pattern deviation fields. The slope of log-scale RNFL thickness versus VF defect was significantly steeper for the MvD+ than the MvD– group, as determined by both total and pattern deviation maps (P = 0.004 and <0.001, respectively). Both total and pattern VF deviation were significantly worse in the MvD+ than in the MvD– group (P = 0.002 and 0.007, respectively). Same results were obtained in subgroup analyses for eyes with thick and thin RNFL thickness (all P ≤ 0.027). These data suggest that parapapillary MvD is associated with poorer function of the remaining axons in eyes with POAG.

Highlights

Glaucoma is characterized by a progressive loss of retinal ganglion cells (RGC) and their axons, accompanied by a reduction in visual field (VF) sensitivity
Our group demonstrated that the parapapillary choroidal microvasculature dropout (MvD) defined by the OCTA corresponds to the true perfusion defect determined by indocyanine green angiography (ICGA)[10]
Parapapillary choroidal MvD may be attributable to vascular compromise in the common arteriole before it divides into choroidal and optic nerve head (ONH) branches

Summary

Introduction

Glaucoma is characterized by a progressive loss of retinal ganglion cells (RGC) and their axons, accompanied by a reduction in visual field (VF) sensitivity. At a given level of retinal nerve fiber layer (RNFL) thickness, the degree of VF loss can vary widely. In clinical settings, this poses a diagnostic dilemma regarding the likelihood of disease and whether the severity of glaucoma should be primarily gauged on the basis of structure or function or a combination of both[1]. Ischemia in the area of the MvD may disrupt the blood–optic nerve barrier, resulting in the release of vasoactive or toxic substances into the ONH21 These substances may have a negative effect on the function of optic nerve axons

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