Peripapillary retinal artery in first diagnosed and untreated normal tension glaucoma

Abstract Backgroud Glaucoma, an important cause of visual impairment in many countries, remains a common eye condition due to difficulties in its early diagnosis. We analyzed the characteristics of retinal arteries to add a valuable technology for helping the normal tension glaucoma (NTG) diagnosis. Methods This study included 51 patients with newly diagnosed NTG with hemifield defects and 60 age-matched controls. Peripapillary retinal arteriolar calibers (PRACs) photoed by non-mydriatic retinal camera were measured using ImageJ by two masked readers. We also performed spectral-domain optical coherence tomography to evaluate retinal nerve fiber layer thickness (RNFLT) and optic disc parameters. Their relations to retinal arteriolar calibers were investigated by univariate and multivariate linear regression. The area under the receiver operating characteristic curve (AUROC) was used to confirm the powers to detect NTG by PRACs. Results PRACs in four quadrants were significantly reduced in individuals with first diagnosed NTG (82 ± 15.1 μm, 80 ± 13.6 μm, 71 ± 11.6 μm, and 64 ±10.0 μm) compared with those in age-matched controls (101 ± 9.8 μm, 105 ± 8.7 μm, 90 ± 7.5 μm, and 82 ± 9.8 μm). Superotemporal and inferotemporal PRACs in the visual field-affected hemifield were narrower than those in the unaffected hemifield in NTG group (P≤0.004). Temporal PRACs in the RNFL unaffected hemifield were significantly narrower than in healthy eyes (P<0.001). Superotemporal PRAC showed a significant correlation with superior RNFLT (β=0.551, P<0.001), and a similar relationship was found between inferotemporal PRAC and inferior RNFLT (β=0.296, P=0.050). These associations were independent of IOP. The diagnostic capability of temporal PRACs was satisfactory (superotemporal PRAC; AUROC 0.983, cut-off value 84.7 μm, inferotemporal PRAC; AUROC 0.946, cut-off value 94.2 μm). Conclusions Superotemporal PRAC and inferotemporal PRAC are valid parameters for discriminating patients with NTG. And it is likely that narrowed peripapillary vessels preceded the RNFL damage detected by digital retinal camera.