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Purpose: To evaluate the relationship between the ischemic index and the oxygen saturation in retinal vessels in patients with retinal vein occlusion., Design: Prospective, cross-sectional study., Methods: We performed a prospective study. The cohort consisted of 43 eyes of 43 patients with retinal vein occlusions (RVO), 23 of whom had central retinal vein occlusions (CRVO) and 20 who had branch retinal vein occlusions (BRVO). We evaluated the retinal vessel saturation using an automatic retinal oximetry device. The retinal ischemic index (ISI) was determined using ultra-widefield fluorescein angiography., Results: Mean arterial saturation (±SD) was 100% ± 11%, mean vein saturation was 52% ±13%, and mean A-V difference was 48% ± 16% in eyes with BRVO. The average ISI in the same group was 0.48 (range 0-1). There was no statistically significant correlation between the retinal ischemic index and retinal saturation in the BRVO group. The affected eye in the CRVO group had a mean arterial saturation of 101% ± 6%, vein saturation of 44% ± 11 % and A-V difference of 58% ± 10%. The average ISI in the CRVO group was 0.54 (range 0-1). A statistically significant negative correlation between ISI and vein saturation was found in the CRVO group (r = -0.686; P =.0003). A significant positive correlation between ISI and the A-V difference was found in the CRVO group (r = 0.893; P <.0001)., Conclusions: Oxygen saturation in the retinal vein and the arteriovenous difference correlated with the ischemic index in CRVO patients. No correlation was found for BRVO patients., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Aim: To determine if oxygen saturation in retinal vessels depends on the degree of diabetic retinopathy., Material and Methods: A prospective study comparing values of oxygen saturation in retinal arteries, veins, and arterio - venous (A-V) difference in healthy persons and in patients with diagnosed diabetes. The study included 114 eyes of 76 patients with diagnosed diabetes, and 57 eyes of 57 patients without diabetes as a control group., Results: The average retinal arterial saturation in patients without diabetes was 96.5 ± 2.6 %, and increased in patients with severe non-proliferative or proliferative diabetic retinopathy to 100.5 ± 5.6 %. The average venous saturation in patients without diabetes was 62.3 ± 7.4 % and increased to 74,0 ± 7.2 % in patients with severe non-proliferative diabetic retinopathy., Conclusion: In patients with diabetic retinopathy, we confirmed the increase of hemoglobin oxygen saturation as in the arterial as in the venous blood in retinal vessels; and significant decrease of arterio-venous difference according to the severity of diabetic involvement was confirmed as well.Key words: automatic retinal oxymetry, diabetic retinopathy, oxygen saturation, Oxymap.

Purpose: To determine the effect of pars plana vitrectomy (PPV) on oxygen saturation in retinal vessels in patients with diabetes and non-diabetes after a 1-year follow-up., Methods: This was a prospective consecutive interventional case series in 82 eyes in 82 patients. The sample consisted of 25 patients with non-proliferative diabetic retinopathy with macular oedema based on vitreoretinal traction or epiretinal membrane (ERM) and 57 non-diabetic patients with macular hole and ERM. Automatic retinal oximetry (Oxymap Inc.) was used on all patients 24 hr prior to PPV, and it was also used 7 and 52 weeks after PPV (classic 20G or sutureless 23G). We analysed the data according to subgroup diagnosis and lens status., Results: Arterial saturation increased significantly from 96.4 ± 2.9% at baseline to 96.6 ± 3.4% at week 7 and 97.3 ± 3.4% at week 52 (p < 0.0001; Friedman test). Vein saturation also increased significantly from 63.5 ± 7.9% at baseline to 66.1 ± 7.7% and 67.0 ± 7.2% at weeks 7 and 52 (p < 0.0001; Friedman test). The value of the arteriovenous (A-V) difference decreased significantly after vitrectomy from 32.8 ± 7.5% at baseline to 30.5 ± 7.5% and 30.3 ± 7.0% at weeks 7 and 52 (p < 0.0001; Friedman test). The subgroup analysis revealed that in patients with diabetes, there were no statistically significant changes in oxygen saturation in blood vessels or in the A-V difference after PPV. After vitrectomy, retinal vessel diameter reduced by about 3.5% in both groups of patients. Further, the analysis revealed that opacification of the lens leads to a decrease in oxygen saturation in contrast to a clear lens and pseudophakic IOLs., Conclusion: Oxygen saturation is higher in the retinal veins and arteries after PPV in patients with non-diabetes, and this lasts for at least 52 weeks. In contrast, in patients with diabetes, there is no increase in oxygen saturation in the retinal vessels after vitrectomy. After vitrectomy, retinal vessel diameter reduced in both groups of patients. Further, the nuclear cataract progression has substantial effect on oximetry results. Patients with nuclear cataract exhibited an increase in saturation in both arteries and veins, but the A-V difference remained the same., (© 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)