Purpose: To investigate whether there are differences in retinal oxygen saturation in upper and lower visual field hemispheres in primary open-angle glaucoma (POAG) and in normal-tension glaucoma (NTG). Methods: This study enrolled POAG and NTG patients exhibiting differences between the upper and lower total deviation (TD) that were either more than 10 or &lt
5 dB. Retinal oxygen saturation measurements in these patients with glaucoma were performed by a non-invasive spectrophotometric retinal oximeter. The Student's t-test was used for statistical analysis. Results: Evaluations of the worse and better hemifields in the patients with POAG who exhibited differences in the upper and lower hemifield TD that was &lt
5 dB (n = 25) showed that there were no statistically significant differences for the retinal venous saturation of oxygen (SaO2). However, there was a higher mean SaO2 in the worse (57.0 ± 7.5%) versus the better (54.3 ± 7.0%) hemifield in the patients with NTG (n = 22
p = 0.007). Evaluations of the patients with more than a 10-dB difference in the upper and lower hemifield TD showed statistically significant differences for the retinal venous SaO2 in the venous vessels between the POAG (n = 19) and the NTG (n = 26) patients. Conclusion: Although there was no significant difference in retinal SaO2 in the venules between the better and worse hemifield when the difference between the better and worse hemifield in the patients with POAG was &lt
5 dB, there was a higher SaO2 in the venous vessels in the worse hemifield in the patients with NTG.