Purpose:
To test whether glaucomatous visual field defects are associated with changes in retinal vascular oxygen saturation in patients with open-angle glaucoma (OAG).
Methods:
Thirty nine patients with OAG with and without pseudoexfoliation underwent retinal oximetry and Octopus 123 visual field test. The mean visual field defect was evaluated in relation to oxygen saturation in corresponding retinal blood vessels (n=34). We also compared oxygen saturation between areas with asymmetrical visual field defects within the same eye (n=13). Statistical analysis was performed with Pearson’s Correlation and Student's t-test.
Results:
Oxygen saturation in retinal venules was correlated with visual field mean defect (r=0.4, p=0.02) whereas no correlation was found in retinal arterioles (r=0.06, p=0.7). Correlation was also observed between arteriovenous difference (r=-0.3, p=0.05) and scotoma (see figure). In patients with asymmetrical visual field defects within the same eye, the mean arteriolar oxygen saturation was lower (98±5%) in areas corresponding to a visual field defect compared to healthier areas (102±6%, p=0.04). The arteriovenous difference was also lower in areas corresponding to visual field defect (30±10%) than in healthier areas (37±10%, p=0.04). No difference was found in venules (p=0.3).
Conclusions:
Deeper glaucomatous visual field defects are associated with decreased arteriovenous difference in retinal oxygen saturation, possibly indicating decreased oxygen delivery to the retina. The preliminary data suggests disturbed oxygen metabolism in the glaucomatous retina.
Keywords: retina • oxygen • imaging/image analysis: non-clinical