First Author: M.Sin CZECH REPUBLIC
Co Author(s): I. Sinova J. Rehak
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To determine the effect of pars plana vitrectomy (PPV) on oxygen saturation in retinal vessels in diabetic and non-diabetic patients after a one year follow up.
Department of Ophthalmology, University Hospital Olomouc, I.P. Pavlova 6, 77900, Olomouc, Czech Republic
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 edema and 57 non diabetic patients with macular hole and epiretinal membrane. Automatic retinal oximetry (Oxymap inc., Reykjavik, Iceland) was used on all patients 24 hours prior to PPV and 7 and 52 weeks after PPV (classic 20G or sutureless 23G). We analysed the data according to subgroup diagnosis and lens status.
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; Friedmann 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; Friedmann test). The value of the 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; Friedmann test). The subgroup analysis revealed that in diabetic patients, there were no statistically significant changes in oxygen saturation in blood vessels or in the A-V difference after PPV. Further, the analysis revealed that opacification of the lens leads to a decrease in oxygen saturation in contrast to clear lens and pseudophakic IOLs.
Oxygen saturation is higher in the retinal veins and arteries after pars plana vitrectomy in non diabetic patients and this lasted for at least 52 weeks. In contrast, in diabetic patients there was no increase in oxygen saturation in retinal vessels after vitrectomy. The lens status too, has significant effect on oximetry results and this should be born in mind for future clinical studies.