title: Effect of Ginkgo biloba on visual field and contrast sensitivity in Chinese patients with normal tension glaucoma: a randomized, crossover clinical trial.
abstract: OBJECTIVE
  We evaluated the effect of ginkgo biloba extract on visual field defect and contrast sensitivity in a Chinese cohort with normal tension glaucoma.
  
  
  METHODS
  In this prospective, randomized, placebo-controlled crossover study, patients newly diagnosed with normal tension glaucoma, either in a tertiary glaucoma clinic (n = 5) or in a cohort undergoing routine general physical examinations in a primary care clinic (n = 30), underwent two 4-week phases of treatment, separated by a washout period of 8 weeks. Randomization determined whether ginkgo biloba extract (40 mg, 3 times per day) or placebo (identical-appearing tablets) was received first. Primary outcomes were change in contrast sensitivity and mean deviation on 24-2 SITA standard visual field testing, while secondary outcomes included IOP and self-reported adverse events.
  
  
  RESULTS
  A total of 35 patients with mean age 63.7 (6.5) years were randomized to the ginkgo biloba extract-placebo (n = 18) or the placebo-ginkgo biloba extract (n = 17) sequence. A total of 28 patients (80.0%, 14 in each group) who completed testing did not differ at baseline in age, sex, visual field mean deviation, contrast sensitivity, IOP, or blood pressure. Changes in visual field and contrast sensitivity did not differ by treatment received or sequence (P > 0.2 for all). Power to have detected a difference in mean defect as large as previously reported was 80%.
  
  
  CONCLUSIONS
  In contrast to some previous reports, ginkgo biloba extract treatment had no effect on mean defect or contrast sensitivity in this group of normal tension glaucoma patients. (http://www.chictr.org number, ChiCTR-TRC-08000724).
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Xinxing
authors.initials: X
authors.lastname: Guo
authors.forename: Xiangbin
authors.initials: X
authors.lastname: Kong
authors.forename: Rui
authors.initials: R
authors.lastname: Huang
authors.forename: Ling
authors.initials: L
authors.lastname: Jin
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Ding
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.forename: Xing
authors.initials: X
authors.lastname: Liu
authors.forename: Mehul Chimanlal
authors.initials: MC
authors.lastname: Patel
authors.forename: Nathan G
authors.initials: NG
authors.lastname: Congdon
mesh_terms: D000284:Administration, Oral; D000368:Aged; D002681:China / Q000453:epidemiology; D015350:Contrast Sensitivity / Q000187:drug effects*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D020441:Ginkgo biloba; D006801:Humans; D057066:Low Tension Glaucoma / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000008:administration & dosage*; D015995:Prevalence; D011446:Prospective Studies; D016896:Treatment Outcome; D014794:Visual Fields / Q000187:drug effects*
chemical_list: D010936:Plant Extracts
keywords: Ginkgo biloba; contrast sensitivity; normal tension glaucoma; visual field