Oxygen venular saturation correlates with a functional loss in primary open-angle glaucoma and normal-tension...

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).

This study enrolled POAG and NTG patients exhibiting differences between the upper and lower total deviation (TD) that were either more than 10 or <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.

Evaluations of the worse and better hemifields in the patients with POAG who exhibited differences in the upper and lower hemifield TD that was <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.

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 <5 dB, there was a higher SaO₂ in the venous vessels in the worse hemifield in the patients with NTG.