Quantitative Analysis of Retinal and Choroidal Vascular Parameters in Patients With Low Tension Glaucoma

Precis: By using OCT-A, we observed a reduction of the superficial macular, peripapillary, and optic nerve, as well as the choriocapillaris in eyes with low tension glaucoma, compared with normal controls. Purpose: The purpose of this study was to investigate macular and optic disc vascular parameters in patients with low tension glaucoma (LTG) using optical coherence tomography angiography (OCTA). Methods: In this cross-sectional study, images were prospectively acquired from both eyes of 26 patients with clinically diagnosed LTG and 22 age-matched volunteers with normal healthy eyes using the Zeiss swept-source (SS) OCTA (Plex Elite 9000, Carl Zeiss Meditec). Perfusion density (PD) and vessel length density (VLD) within a 5mm diameter circle centered over the macula and optic nerve head were analyzed. Results: The final analysis cohort included 49 eyes with LTG and 40 healthy control eyes. Mean age was 60 +/- 10 years in the LTG group and 60 +/- 17 years in the control group. The LTG group had a statistically significant reduction in PD of the choriocapillaris (CC) compared with normal controls (71.74 +/- 8.37% vs. 80.48 +/- 3.84%; P< 0.001). There was no statistically significant difference in PD between the LTG and control groups for the superficial vascular plexus (SVP), deep capillary plexus (DCP) or the optic nerve head and peripapillary area (ONH+ PP) (P> 0.05). The LTG group did show statistically significant reductions in VLD compared with normal controls for the SVP (2083.64 +/- 153.76mm/mm2 vs. 2154.63 +/- 144.18mm/ mm2; P= 0.03) and ONH + PP (1813.76 +/- 271.69mm/mm2 vs. 1950.23 +/- 169.33mm/mm2; P= 0.03), whereas the DCP VD was similar between the 2 groups (P> 0.05). Conclusions: Eyes with low tension glaucoma seems to show a lower CC perfusion density, as well as a lower SVP and ONH+ PP vessel length density compared to normal eyes.