ObjectiveTo measure and analyze the oxygen saturation and retinal blood vessel diameter in the eyes of patients with convalescence Vogt-Koyanagi-Harada (VKH) syndrome. MethodsIn this cross-sectional study, 28 eyes of 14 patients with convalescence VKH syndrome (VKH group) and 20 eyes of 10 healthy subjects (control group) were enrolled. The oxygen saturation and retinal blood vessel diameter were detected by spectrophotometric oximetry unit. Retinal images were collected using filters with wavelengths of 570 nm and 600 nm in the darkroom by the same technologist and then the fused image was obtained. The oxygen saturation of retinal vessels was marked in different colors. The measurement was repeated 2-3 times for each patient, then take an average. A top-quality image in each eye was selected to detect the oxygen saturation and diameter of retinal vessel which located in 1.5-3.0 disc diameter from the optic disc. Image analysis and data acquisition were completed by another technologist. ResultsRetinal venous oxygen saturation was (54.34±8.05)% in the VKH group and (60.07±7.91)% in the control group. The former was lower than the latter, the difference was significant (t=2.443, P=0.017). The mean diameter of retinal arteries was (102.8±18.1) μm in the VKH group and (112.9±19.8) μm in the control group. The former was smaller than the latter, the difference was significant (t=2.406, P=0.018). There was no significant difference of the mean diameter of retinal veins, oxygen saturation of retinal arteries and the arterial-venous difference between two groups (t=-0.330, 0.804, -0.631; P=0.743, 0.403, 0.536). ConclusionsRetinal venous oxygen saturation and the mean diameter of retinal arteries are significantly decreased in patients with VKH syndrome. There is no significant difference of diameter of retinal veins, oxygen saturation of retinal arteries and the arterial-venous difference between VKH syndrome patients and healthy subjects.
ObjectiveTo observe the difference of retinal vessel oxygen saturation in glaucoma and normal eyes. MethodsA cross sectional study design was performed. Fifty eyes of 30 glaucoma patients (glaucoma group) and 41 eyes of 27 age-and sex-matched healthy subjects (control group) were included. Retinal vessel oxygen saturation was measured with a spectrophotometric retinal oximeter in darkness and visual fields were obtained by Humphrey filed analyzer. The glaucoma eyes were divided into two groups: mean defect (MD)<6 dB (28 eyes) and MD≥6 dB (22 eyes) according to mean defect of visual field. ResultsRetinal arteriolar oxygen saturation values in glaucoma group and control group were (94.52±6.51)% and (93.47±6.30)% respectively. No statistical difference was found in retinal oxygen saturation in arterioles (H=-0.949, P=0.343). Retinal venous oxygen saturation values in glaucoma group and control group were (57.57±7.96)% and (52.60±7.70)% respectively. The retinal venous oxygen saturation values in glaucoma group was higher than that in control group (H=-3.318,P=0.001). The retinal arteriovenous difference in glaucoma group and control group were (36.59±4.69)% and (42.41±6.73)% respectively. The retinal arteriovenous difference in glaucoma group was lower than that in control group (H=-4.148,P<0.01). The retinal arteriolar oxygen saturation values in glaucoma eyes with MD<6 dB and MD≥6 dB were (93.38±6.33)% and (95.71±6.54)% respectively, with no statistical difference (H=-1.857,P=0.063). Retinal venous oxygen saturation values in glaucoma eyes with MD<6 dB and MD≥6 dB were (54.83±6.10)% and (61.07±8.79)% respectively. The retinal venous oxygen saturation values in MD≥6 dB glaucoma eyes was higher than that in MD<6 dB glaucoma eyes (H=-2.599, P=0.009). The retinal arteriovenous difference in glaucoma eyes with MD<6 dB and MD≥6 dB were (38.12±4.34)% and (34.64±4.49)% respectively. The retinal arteriovenous difference in MD≥6 dB glaucoma eyes was lower than that in MD<6 dB glaucoma eyes (H=-2.463,P<0.05). ConclusionsCompared with healthy eyes, there is no change in the retinal arteriolar oxygen saturation, but the retinal venous oxygen saturation is higher and the retinal arteriovenous difference is lower. This feature is more obvious in MD≥6 dB glaucoma eyes.
ObjectiveTo investigate the diagnostic value of oximetry in sleep apnea hypopnea syndrome (SAHS). MethodsAdult patients suspected for SAHS were enrolled between May 2010 and May 2013. The patients underwent both polysomnography (PSG) and oximetry for further diagnosis. Apnea hyponea index (AHI) and oxygen desaturation index four (ODI4) were calculated on a single night. The relationship between AHI and ODI4 were analyzed. ResultsA total of 628 adult patients were recruited.ODI4 was linearly correlated with AHI with a regression coefficient of almost 1. The cut-off values of ODI4 for indentifing SAHS and moderate to severe SAHS were 10 events per hour and 20 events per hour, with specificities of 99.9% and 99.3%, and AUCs of 0.931 and 0.934, respectively. Female, lower weight and less severe SAHS patients were easily misdiagnosed. ConclusionsThere is a high agreement between AHI and ODI4. Oximetry is less likely misdiagnose SAHS.
Objective To evaluate the correlation of oxygen saturation of retinal vessels and diabetic retinopathy (DR) stages or HbA1c level in patients with DR. Methods Cross sectional study. A total of 102 patients (102 eyes) with DR and 20 age-matched healthy controls (20 eyes) (normal control group) were enrolled in this study. DR patients were divided into mild and moderate non-proliferative DR (NPDR) group (55 patients), severe NPDR group (26 patients) and proliferative DR (PDR) group (21 patients). DR patients were also divided into 3 groups according to the HbA1c level including HbA1c＞9% (8 patients), HbA1c 7% – 9% (33 patients) and HbA1c＜7% group (61 patients). The oxygen saturation of retinal vessel was measured by spectrophotometric oximetry unit in the retinal vessels with a diameter greater than 60 μm in the area around the optic disc. Results The retinal artery oxygen saturation of patients in severe NPDR group was significantly higher than that in mild to moderate NPDR group and normal control group (F=13.670,P＜0.05). The retinal vein oxygen saturation of patients in PDR group was significantly higher than that in mild to moderate NPDR group and normal control group (F=6.379,P＜0.05). The difference between retinal artery and vein oxygen saturation of patients in severe NPDR group was significantly bigger than that in mild to moderate NPDR group and PDR group (F=5.536,P＜0.05). The retinal artery and vein oxygen saturation in patients of HbA1c＞9% group were significantly higher than that in HbA1c 7% – 9% group and HbA1c＜7% group (F=9.989, 10.208;P＜0.05). The differences between retinal artery and vein oxygen saturation were same between patients in HbA1c＞9%, HbA1c 7%＜9% and HbA1c＜7% group (F=1.836,P＞0.05). Conclusions The retinal artery and vein oxygen saturation in DR patients are related to the DR stages. Severe NPDR patients show the highest retinal artery oxygen saturation as well as biggest difference between retinal artery and vein oxygen saturation. There is also a trend that retinal vein oxygen saturation increases with higher DR stages. In addition, there is a positive correlation between the levels of HbA1c and retinal vessel oxygen saturation.
Objective To analysis the effect of lens opacity on the measurement of retinal vessel oxygen saturation. Methods This was a cross sectional study. Forty four eyes of 44 patients with different degrees of lens opacity were enrolled. There were 23 males and 21 females. The patients aged from 48 to 84 years, with the mean age of (71.8±10.3) years. The mean best corrected visual acuity was 0.65±0.22. The mean intraocular pressure was (14.2±4.3) mmHg (1 mmHg=0.133 kPa). The mean equivalent spherical degree was (−0.05±2.10) D. The opitical quality analysis system was applied to measure intraocular objective scattering index (OSI) caused by lens opacity. According to the OSI, the opacity of lens was divided into four groups. Patients with OSI value ＜1.0 was grouped to level 1, which indicated that the lens were basically transparent; patients with OSI value between 1.0 and 3.0 was grouped to level 2, which indicated early cataract; patients with OSI value between 3.0 and 7.0 was grouped to level 3, which indicated progressive cataract; patients with OSI value ＞7.0 was grouped to level 4, which indicated the mature stage of cataract. The retinal oximeter Oxymap T1 was used to capture the fundus images under different wavelengths. Pearson correlation analysis was used to analyze the correlation between retinal oxygen saturation and age, intraocular pressure, equivalent spherical degree and OSI. One way ANOVA was used to analyze the difference of retinal oxygen saturation among groups. Results The mean retinal arterial oxygen saturation, venous oxygen saturation and arteriovenous difference was (90.70±6.46)%, (47.34±13.51)%, (43.36±10.09)%, respectively. The correlations of retinal arterial oxygen saturation, venous oxygen saturation and arteriovenous difference with age, intraocular pressure, equivalent spherical degree was not statistically significant (all P＞0.05). The retinal arterial oxygen saturation and venous oxygen saturation was negatively correlated with OSI (r=−0.462,−0.500; P=0.002, 0.001), the arteriovenous difference and OSI was positively correlated (r=0.373, P=0.013). According to lens opacity, there were 11 eyes in level 1, 9 eyes in level 2, 14 eyes in level 3, 10 eyes in level 4. There were significant differences of retinal artery and venous oxygen saturation among different lens opacity levels (F=5.340, 4.710; P=0.003, 0.007); meanwhile, the arteriovenous difference was not significantly different (F=2.048, P=0.123). The retinal arterial oxygen saturation and venous oxygen saturation was significantly lower in the level 4 lens opacity group than any other three groups (all P＜0.05), but there was no statistically significant difference among level 1 to level 3 lens opacity group. Conclusion The effect of lens opacity of level 1 to level 3 is limited on the measurement of retinal oxygen saturation, but level 4 lens opacity will cause decrease of retinal artery and venous oxygen saturation.
The retinal blood oxygen quantification method is a fast and non-invasive new retinal vascular imaging technology, which is used to reflect the metabolism of retinal blood oxygen and the micro-circulation of whole body by measuring, analyzing and quantifying the blood oxygen saturation of the main arteries and veins of the retina. The circulation state provides a reliable basis for medical diagnosis. Retinal blood oxygen saturation can be used as a biomarker for the diagnosis and evaluation of ophthalmologic and brain diseases such as diabetic retinopathy, central retinal vein occlusion, retinitis pigmentosa, glaucoma and Alzheimer's disease.