Relationship between oxygen saturation of the retinal vessels and visual field defect in glaucoma patients: comparison with each hemifield

Abstract

Purpose : To investigate the relationship between visual field defects in the upper and lower hemifields and the corresponding oxygen saturation of the retinal vessels in patients with glaucoma.

Methods : This study enrolled 44 glaucoma patients who had more than a 10 dB difference between the upper and lower total deviation (TD). Retinal vessel oxygen saturation was measured with a non-invasive spectrophotometric retinal oximeter. The hemifields in one eye of each patient were divided into worse (worse TD) and better (better TD) hemifield areas. We also examined an additional 40 glaucoma patients who had less than a 5 dB difference between upper and lower TD. Statistical analysis was performed using a Student’s t-test.

Results : Mean venous saturation of oxygen (SaO₂) was higher in the worse (59.0 ± 8.0%) versus the better (55.4 ± 7.2%) hemifield (P < 0.01). The mean arteriovenous difference in the SaO₂ was lower in the worse (44.4 ± 9.0%) versus the better (48.6 ± 11.4%) hemifield (P = 0.02). However, no statistical difference was found for the retinal SaO₂ in the venous vessels or for the arteriovenous difference between the worse and better hemifield in patients with less than a 5 dB difference in the upper and lower hemifield TD.

Conclusions : Advanced glaucomatous visual field defects are associated with increased SaO₂ in the venous vessels and a decreased arteriovenous difference in the SaO₂. Data suggest that there is a reduced retinal oxygen consumption in eyes with glaucomatous damage due to retinal ganglion cell loss.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.