AIM: To investigate the effect of crystal turbidity on retinal oxygen saturation in patients with diabetic cataract.

METHODS:This was a cross-sectional study. Totally 68 patients with 68 eyes of diabetic cataract admitted to our hospital from June 2017 to December 2017 were selected as subjects. Retinal oximetry was used to measure the blood oxygen saturation of the retinal veins, veins, and their supraorbital, nasal, subnasal, and infraorbital branches. The objective scatter index(OSI)of the eye was measured by Visual Quality Analysis System II, and the degree of opacity of the lens was graded according to OSI.

RESULTS:The blood oxygen saturation of the retinal artery and its branches in this group were 101.39%±10.84%, 106.19%±11.40%, 103.22%±10.91%, 102.36%±20.31%, and 101.29%±13.88%, respectively. The oxygen saturation of the retinal vein and its branches were 62.51%±8.95%, 66.37%±10.74%, 64.81%±8.97%, 58.37%±13.85%, and 58.66%±19.94%, respectively. The difference between arteriovenous oxygen saturation was 40.72%±12.08%. In this group of patients, 68 patients with 68 eyes had an OSI value of 4.21±3.14. Among them, 15 eyes were turbid at the first stage, 14 eyes were turbid at level 2, 23 eyes were turbid at level 3, and 16 eyes were turbid at level 4. Pearson correlation analysis showed that the retinal veins, veins and their branches were negatively correlated with OSI(both P<0.01). The difference in retinal arterial and venous oxygen saturation was positively correlated with OSI(P<0.01). There were significant differences in the blood oxygen saturation between the retinal veins, veins and their branches in patients with different degrees of lens opacity(P<0.05). The retinal arterial, venous and branch oxygen saturation of patients with opacity of lens 4 was significantly lower than that of patients with opacity of lens 1, 2, and 3, and the difference was statistically significant(P<0.05). There were no significant differences in blood oxygen saturation between the patients with opacity of lens 1, 2, and 3(P>0.05). There was no significant difference in the difference of arteriovenous oxygen saturation between the patients with different degrees of lens opacity(P>0.05).

CONCLUSION: In patients with diabetic cataract, when the degree of lens opacity is 1 to 3, the degree of abnormality of retinal blood oxygen metabolism is not obvious. When the degree of lens opacity reaches 4, the blood oxygen saturation of the retinal veins, veins and their branches will decrease.