Preoperative and postoperative measurements of retinal vessel oxygen saturation in patients with different grades of cataracts

PurposeTo assess the retinal vessel blood oxygen saturation preoperatively and postoperatively in patients with different grades of cataracts. MethodsThis study included 40 eyes from 40 patients with senile cataracts ranging from grade 1 to 3. All 40 eyes received standard phacoemulsification and intraocular lens implantation. The mean retinal arterial and venular oxygen saturation (SO2) levels were measured using the Oxymap system prior to, immediately after and 3months after cataract surgery. The arterial-venular difference (AVD) was calculated as the difference between the arterial and venular saturations. Linear regression analysis was performed to identify the relationship between the lens density grades and changes in the measured retina vessel SO2. ResultsThe mean age of the subjects was 64.17.8years, and 14 (35%) were male. The mean SO2 level increased in the retinal arterioles from 90.5 +/- 7.8% to 95.0 +/- 6.7% immediately postoperatively and to 98.3 +/- 5.3% at 3months after surgery (p<0.001). The mean venular saturation levels were 43.4 +/- 9.7%, 58.0 +/- 8.5% and 61.9 +/- 6.5% at baseline, immediately after and at 3months postoperatively, respectively, with a statistically significant increase after surgery (p<0.001). The mean AVD significantly decreased from 47.1 +/- 8.9% before surgery to 37.1 +/- 7.3% immediately after and 36.4 +/- 6.4% 3months after surgery (p<0.02). A linear regression model indicated that denser lens opacity was significantly associated with a larger amplitude of the venular SO2 level and the AVD after cataract surgery: change of venous SO2=5.934-0.191xAge+13.534xLens Grade (age: p=0.586; lens grade: p<0.001); change in AVD=-7.438-0.037xAge+7.744xLens Grade (age: p=0.917; lens grade: p=0.031). ConclusionsRetinal arterial and venular oxygen saturation levels are significantly increased after cataract surgery, and increase rates vary with the preoperative grading of lens density.