Correlation Between Peripapillary Choroidal Thickness and Retinal Vessel Oxygen Saturation in Young Healthy Individuals and Glaucoma Patients

PURPOSE: To investigate the correlation between peripapillary choroidal thickness (CT) and retinal vessel oxygen saturation (SO2) in young healthy individuals and open-angle glaucoma (OAG) patients. METHODS: Fifty-four young healthy volunteers (aged 21.6 ± 1.1 years) and 48 OAG patients (aged 72.0 ± 9.1 years, visual field mean deviation -9.0 ± 8.1 dB) were included. Peripapillary CT was obtained using enhanced depth imaging optical coherence tomography (EDI-OCT). Arterial (SaO2) and venous (SvO2) retinal oxygen saturation were measured by a spectrophotometric retinal oximeter. RESULTS: Arterial and SvO2 retinal oxygen saturation were significantly higher in the glaucoma group (95.1 ± 3.3% vs. 92.3 ± 3.0% and 60.8 ± 6.3% vs. 55.4 ± 4.6%, P < 0.001, respectively), while arteriovenous oxygen difference was significantly lower (34.4 ± 6.0% vs. 36.8 ± 3.8%, P = 0.014). Arterial and SvO2 retinal oxygen saturation were positively correlated with peripapillary CT in the healthy group (Spearman's ρ = 0.48, P < 0.001 and ρ = 0.41, P = 0.002, respectively), but not in the glaucoma group (P > 0.05). Multivariate analysis confirmed that these findings were independent of age, intraocular pressure, and mean arterial blood pressure and revealed a negative correlation between arteriovenous oxygen difference and CT in the healthy group (β = -0.337, P = 0.03). CONCLUSIONS: In this study, we found a significant positive correlation between retinal vessel SO2 and peripapillary CT in young healthy individuals, but not in open-angle glaucoma patients. Further research is warranted to investigate whether the lack of correlation reflects a disturbance in the blood flow regulation in glaucoma patients. (ClinicalTrials.gov number, NCT01840202.).