Abstract
Purpose: :
The noninvasive measurement of oxygen saturation in retinal arteries and retinal veins and capillary systemic oxygen saturation in normals and patients with BRVO.
Methods: :
The determination of retinal oxygen saturation was performed using the Imaging Spectrometer. The basis for the non-invasive estimation of the oxygen saturation is different extinction spectra of hemoglobin and oxyhemoglobin. The measurements of the reflectance spectra were performed in a wavelength range from 400 nm to 700 nm. The retinal oxygen saturation was measured with an entrance slit of 1.5 mm, spectral resolution of Δ < 2m, and local resolution Δs < 7.8µm.The determination of capillary systemic oxygen saturation was performed with blood gas analyser Radiometer ABL 510.We measured 83 healthy eyes, 23 eyes with retinal vein occlusion of nonischemic type and 15 eyes with retinal vein occlusion of ischemic type. The type of retinal vein occlusion (ischemic or nonischemic) was determined by fluorescein angiography.
Results: :
In normals the retinal oxygen saturation was in average 91%+-5% in arteries and 57% +-8% in the veins.In patients with venous retinal occlusion of nonischemic type the oxygen saturation was in average 88.5% +-3.2% in retinal arteries and 58.4% +-7.8% in retinal veins. In patients with venous retinal occlusion of ischemic type the oxygen saturation was in average 84.4% +-5.3% in retinal arteries and 36.2% +-6.8% in retinal veins.The comparison with the oxygen saturation in normal eyes shows significant decrease of oxygen saturation in arteries as well as in veins in eyes with venous retinal occlusion of ischemic type (P<0.001).The capillary systemic oxygen saturation in patients with venous retinal occlusion was in average 95%+-3%.
Conclusions: :
In the eyes with BRVO of ischemic type we found a significant decrease of local oxygen saturation in retinal veins and retinal arteries(P<0.001). In the eyes with venous retinal occlusion of nonischemic type we don’t found a significant difference of local oxygen saturation in the retinal arteries and retinal veins in comparition to normals (P=0.09 in arteries and P=0.21 in the veins).In the systemic capillary oxygen saturation we found no significant difference between normals and patients with venous retinal occlusion(P=0.51).
Keywords: retina • ischemia • oxygen