title: Preoperative and postoperative measurements of retinal vessel oxygen saturation in patients with different grades of cataracts.
abstract: OBJECTIVE
  To assess the retinal vessel blood oxygen saturation preoperatively and postoperatively in patients with different grades of cataracts.
  
  
  METHODS
  This 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 3 months 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.
  
  
  RESULTS
  The mean age of the subjects was 64.1 ± 7.8 years, and 14 (35%) were male. The mean SO2level increased in the retinal arterioles from 90.5 ± 7.8% to 95.0 ± 6.7% immediately postoperatively and to 98.3 ± 5.3% at 3 months 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 3 months 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% 3 months after surgery (p < 0.02). A linear regression model indicated that denser lens opacity was significantly associated with a larger amplitude of the venular SO2level and the AVD after cataract surgery: change of venous SO2= 5.934-0.191 × Age + 13.534 × Lens Grade (age: p = 0.586; lens grade: p < 0.001); change in AVD = -7.438-0.037 × Age + 7.744 × Lens Grade (age: p = 0.917; lens grade: p = 0.031).
  
  
  CONCLUSIONS
  Retinal arterial and venular oxygen saturation levels are significantly increased after cataract surgery, and increase rates vary with the preoperative grading of lens density.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Haotian
authors.initials: H
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Wan
authors.initials: W
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Wu
authors.initials: W
authors.lastname: Xiang
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Qianying
authors.initials: Q
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Weirong
authors.initials: W
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Yizhi
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000368:Aged; D002386:Cataract / Q000175:diagnosis* / Q000378:metabolism; D002387:Cataract Extraction; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D011184:Postoperative Period; D057234:Preoperative Period; D011446:Prospective Studies; D012171:Retinal Vessels / Q000378:metabolism*
chemical_list: D010100:Oxygen
keywords: cataract; oxygen saturation; retinal oximetry; retinal vessel blood saturation