Longitudinal change of peripapillary vessel density and retinal nerve fibre layer thickness in normal tension and primary angle closure glaucoma

Abstract

PurposeTo compare the rates of peripapillary vessel density (pVD) loss and retinal nerve fibre layer (RNFL) thinning in normal tension glaucoma (NTG) and primary angle closure glaucoma (PACG).MethodsBaseline age and severity-matched NTG and PACG eyes (75 eyes of 60 patients for each subtype) were observed longitudinally. All participants’ RNFL thickness were measured by optical coherence tomography (OCT); pVD were measured by swept-source OCT-angiography (OCT-A) and quantified by a customised MATLAB program. The rate of pVD loss and RNFL thinning were estimated by linear mixed-effects models.ResultsNTG eyes had significant pVD loss in all sectors (p≤0.05) while PACG eyes’ pVD loss was borderline significant in the global region (p=0.05). Significant RNFL thinning was detected in the inferotemporal and superonasal regions of both groups, and the superotemporal region in the NTG group (all p≤0.02). NTG had faster rate of pVD loss in the global (difference (95% CI) −1.08 (−1.90 to –0.27) %/year), temporal (−1.57 (−2.91 to –0.23) %/year) and superotemporal (−1.46 (−2.65 to –0.26) %/year) regions than PACG (all p≤0.02), without significant difference of the rate of RNFL thinning. A lower baseline mean deviation (MD) was associated with a faster rate of global pVD loss, while a lower baseline pVD was associated with a slower rate of global pVD loss in multivariable analyses (both p≤0.04).ConclusionsNTG had more extensive and faster rate of pVD loss than PACG. Baseline global pVD and MD were independently associated with the rate of pVD loss in NTG.

Longitudinal changes in optical coherence tomography angiography characteristics in normal‐tension glaucoma with or without high myopia

“…In another prospective study with a longer follow-up duration (2.6 years), Hou et al (2020) reported loss rates of macular VD and GCC thickness that were significantly different from zero in 80 eyes of individuals with POAG. In a retrospective study, Chan et al (2022) reported a peripapillary VD loss rate of −1.65%/year and an RNFL thinning rate of −0.25 μm/ year in 75 NTG eyes; however, only the peripapillary VD loss rate differed significantly from zero. Our results are similar with those of the previous studies.…”

“…In a retrospective study, Chan et al. (2022) reported a peripapillary VD loss rate of −1.65%/year and an RNFL thinning rate of −0.25 μm/year in 75 NTG eyes; however, only the peripapillary VD loss rate differed significantly from zero. Our results are similar with those of the previous studies.…”

“…However, longitudinal studies focusing on NTG progression remain scant. Chan et al (2022) and colleagues demonstrated that NTG eyes have faster peripapillary VD loss than do those with primary angle closure glaucoma (PACG), indicating that vascular change may be more important pathogenically in NTG than in PACG.…”

Progressive peripapillary capillary vessel density loss and long‐term visual field progression in Normal tension glaucoma

“…A recent study by Chan et al. (2022) compared the longitudinal changes in peripapillary vessel density (pVD), encompassing both large vessels and capillaries, between NTG and PACG. They observed faster rates of pVD reduction in NTG eyes when compared to PACG despite both groups showing similar rates of VF MD loss and RNFL thinning.…”

“…One possible hypothesis to explain these variations is that microcirculatory insufficiency may play a prominent role in the pathogenesis of glaucoma in NTG (Leung & Tham, 2022). In contrast, it is conceivable that PACG or POAG, particularly high‐tension glaucoma, may rely more heavily on IOP as a driving force (Chan et al., 2022; Gazzard et al., 2003).…”