Retinal Oximetry in Primary Open-Angle Glaucoma

Abstract

PURPOSE. To determine whether retinal vessel oxygen saturation is affected in primary open-angle glaucoma (POAG) patients. METHODS. Retinal oxygen saturation in patients with POAG was measured in retinal vessels with a spectrophotometric retinal oximeter in darkness, and visual fields were obtained. Oxygen tension (Po(2)) was calculated from oxygen saturation values. Statistical analysis was performed using Pearson's correlation and Student's t-test. RESULTS. Mean oxygen saturation in venules was higher in persons with poor visual fields (68% ± 4%, mean ± SD) than in those with good visual fields (62% ± 3%; P = 0.0018). The mean arteriovenous difference in oxygen saturation was lower in persons with poor visual fields (30% ± 4%, n = 9) than in those with good visual fields (37% ± 4%; P = 0.0003; n = 12). No correlation was found between saturation in retinal arterioles and visual field mean defect (n = 31; r = -0.16; P = 0.38). Oxygen saturation in retinal venules correlated positively with worsening visual field mean defect (r = 0.43; P = 0.015). Arteriovenous difference in oxygen saturation decreased significantly as the visual field mean defect worsened (r = -0.55; P = 0.0013). Mean Po(2) in venules was 38 ± 3 mm Hg. It was significantly higher in persons with poor visual field fields (40 ± 3 mm Hg) than in those with good visual fields (36 ± 2 mm Hg; P = 0.0016). CONCLUSIONS. Deeper glaucomatous visual field defects are associated with increased oxygen saturation in venules and decreased arteriovenous difference in retinal oxygen saturation. The data suggest that oxygen metabolism is affected in the glaucomatous retina, possibly related to tissue atrophy.

Oxygen saturation measurements of the retinal vasculature in treated asymmetrical primary open-angle glaucoma using hyperspectral imaging

“…16 Olafsdottir et al 27 reported significantly higher retinal venular oxygen saturations using the same retinal oximeter in glaucomatous eyes with 'poor visual fields' compared with 'good visual fields', 68% ( ± 4%) and 62% ( ± 3%), respectively. Importantly, an earlier study by Hardarson et al 16,27 found comparatively lower retinal mean (±SD) venous oxygen saturation in normal subjects of 55% (±14%). A commonly accepted limitation of the two-wavelength oximetry technique is the tendency to overestimate the true blood oxygen saturation particularly at lower oxygen saturations.…”

Glaucoma and ocular blood flow: an anatomical perspective

“…On the other hand, in all examined eyes arteriolar oxygen saturation and the retinal arteriovenous differences in oxygen correlated strongly with the patient's rim area. Olafsdottir et al found that deeper VF defects in patients with POAG were associated with decreased arteriovenous difference in retinal oxygen saturation and increased oxygen saturation in venules [86]. No correlation was present concerning retinal arterioles and VF defects.…”

DR HAGIS—a fundus image database for the automatic extraction of retinal surface vessels from diabetic patients

“…[9][10][11][12] Furthermore, impairment in ocular blood flow has been implicated in disease states such as diabetes, [31][32][33][34] glaucoma, 35,36 and other ocular diseases. 37 It is crucial for any automatic analysis of the retinal blood vessels that the extraction of these vessels is both possible and accurate enough, Table 3 The effect of diabetic retinopathy, hypertension, AMD, or glaucoma on accuracy, sensitivity, specificity, and kappa statistic for the IB and Gabor filter algorithms.…”