Abstract
Abstract: :
Purpose: To measure non-invasively the oxygen saturation in retinal arteries and veins in eyes with glaucomatous optic nerve atrophy due to open-angle glaucoma. Methods: The measurement of oxygen saturation in retinal vessels was performed by the "Imaging Spectrometer" (Germany, Jena). The non-invasive estimation of the oxygen saturation is based on the different extinction spectra of hemoglobin and oxy-hemoglobin. The reflectance spectra from the fundus were measured with a modified fundus camera RCM 250 combined with an imaging spectrograph CP 200, and an intensified CCD camera. The arterial and venous oxygen saturation in retinal vessels was investigated in 72 eyes of 58 healthy persons, in 57 eyes of 45 patients with primary open-angle glaucoma (POAG), in 62 eyes of 49 patients with Low Tension Glaucoma (LTG). The mean age, mean rim area, and mean defect of the controls, LTG group, and POAG group were: for controls 47±11y, 1.5±0.3mm², 0.6±1.3dB; for the LTG- group 41.8±8y, 1,0±0.7mm², 5.9±4.3dB; for the POAG group 42±10y, 0.9+-4.6mm², 8.1±7.0 dB. For statistical analyses, the non-parametric Mann-Whitney-Wilcoxon and the ANOVA test was used. Results: In eyes with LTG or POAG the oxygen saturation in retinal arteries was significantly decreased compared to control eyes (p<0.000, p<0.043, respectively). The oxygen saturation in retinal arteries averaged 92.4%±3.3%, 89.5±5.2%, and 90.9%±4.5% in controls, LTG, and POAG, respectively. We found no significant difference on venous oxygen saturation. The oxygen saturation in retinal veins averaged 55.4%±6.7%, 58.3±10.4%, and 55.7%±7.8% in controls, LTG, and POAG. The arterial oxygen saturation correlated significantly with the mean defect (R=0.16, p<0.028) and the rim-area (R=0.24, p<0.001). Conclusions: Glaucomatous eyes showed a significantly decreased arterial oxygen saturation in retinal vessels, while the venous oxygen saturation showed no change.
Keywords: 467 metabolism • 554 retina • 428 hypoxia