Thinner Central Corneal Thickness is Associated with a Decreased Parapapillary Vessel Density in Normal Tension Glaucoma

Abstract

This retrospective cross-sectional study, which enrolled 124 normal tension glaucoma (NTG) eyes and 68 healthy eyes as the control, determined the association between central corneal thickness (CCT) and ocular parameters in NTG. CCT was measured using the Pentacam® system, optical coherence tomography angiography (OCT-A) was adopted to measure the peripapillary and macular area VDs, and spatial data were based on the Garway–Heath map as illustrated in OCT-A. Univariate and multivariate linear regressions were used to statistically analyze for associations between CCT and other factors. In this study, the mean age was similar for both the NTG and control groups. The mean CCT of the NTG group was significantly thinner than that of the control group (533.97 ± 33.11 µm vs. 546.78 ± 38.21 µm; p = .022). Considering all the factors, CCT negatively correlated with visual field (VF) pattern standard deviation (univariate, p = .045). To analyze structural and functional factors separately, we found a significant positive correlation between CCT and whole disc radial peripapillary capillary VD (VDRPC; multivariate, p = .019). To analyze the relationship between all factors and sectoral changes in VDRPC, a significant positive correlation was observed between CCT and inferior temporal VDRPC (univariate, p = .039) and inferior nasal VDRPC (VDRPC IN; univariate, p = .048). In conclusion, this novel study shows that among NTG participants, a thinner cornea correlated with weaker biomechanical properties susceptible to optic nerve tissue displacement, especially in response to mild transient elevation of IOP, leads to compromised ocular microcirculation.

Analysis of the Optic Nerve Head Microcirculation Using Optical Coherence Tomography Angiography and the Upstream Macrocirculation Using Color Doppler Imaging in Low-Tension and High-Tension Glaucoma Patients

“…Our findings of lower optic disc perfusion in glaucomatous eyes compared with age-, AL-, and OPP-matched healthy eyes were consistent with the findings from previous studies that showed decreased microvascular density in the optic disc of glaucoma patients [38][39][40][41]. Patients with POAG and LTG have lower perfused capillary density and optic disc perfusion compared with healthy controls [10,12]. Therefore, OCT-A can dif- LTG is less dependent on the IOP and may have a greater component of abnormal vascular function compared with HTG.…”

“…Xu et al [42] found that the peripapillary vascular density was significantly lower in LTG patients than HTG patients. There is no difference in the optic disc perfusion between patients with POAG and LTG who have similar levels of VF damage [12, 43]. POAG patients have lower perfused capillary density compared with LTG patients [10].…”

“…The differences in the vascular hemodynamic parameters between patients with low-tension and high-tension glaucoma (LTG and HTG, respectively) are unclear. Some studies have reported that LTG eyes have a significantly lower peripapillary vessel density (VD) than HTG eyes [11], whereas others have found no significant difference in peripapillary VD between HTG and LTG eyes [12].…”

Characteristic Differences between Normotensive and Hypertensive Pseudoexfoliative Glaucoma

“…Thinner corneas correlated with the response of the corneoscleral shell and the ocular vasculature to IOP-induced stress [47]. A recent study demonstrated thinner CCT is associated with a decreased parapapillary vessel density in NTG [48].…”

Correlation between radial peripapillary vascular density and reduced central corneal thickness in glaucoma suspect patients

“…The chaung study found significant thinner cornea in normal-tension glaucoma. They found also, that reduced corneal thickness in NTG correlated with decreased RPC peripapillary vessel density [ 33 – 35 ].…”