title: Ethnic differences in trabecular meshwork height by optical coherence tomography.
abstract: OBJECTIVE
  Differences in ocular anatomy may contribute to ethnic differences in glaucoma risk. Because the trabecular meshwork (TM) plays an important role in aqueous outflow, its anatomy in relation to at-risk populations may provide insight into a potential contributor to elevated intraocular pressure and thus to probability of glaucoma development.
  
  
  OBJECTIVE
  To investigate whether differences exist in TM height between ethnic groups.
  
  
  METHODS
  This prospective study took place from January 1, 2012, to December 31, 2013. Adult patients who self-reported as being of white, Asian, Hispanic, or African American ethnicity were recruited from ophthalmology clinics at the University of California, San Francisco. The TM height was assessed using spectral-domain anterior segment optical coherence tomography.
  
  
  METHODS
  Trabecular meshwork height was measured from the scleral spur to the Schwalbe line. We hypothesized that ethnicities with a higher prevalence of glaucoma would tend to have shorter TM heights.
  
  
  RESULTS
  We collected data from 460 eyes of 291 participants after excluding 34 optical coherence tomographic scans owing to poor image quality. The final sample was 32.2% white, 45.1% Asian, 10.5% African American, and 12.1% Hispanic. There were 64.2% women, and the mean age was 68.1 years. The mean (SD) TM height among all eyes included in the study was 836 (131) μm. The mean (SD) TM height was characterized among white (851 [131] μm), Asian (843 [126] μm), Hispanic (822 [147] μm), and African American (771 [118] μm) persons. Ethnicity was not associated with TM height overall (P = .23, linear mixed regression model). However, the TM heights of African American participants (771 μm) were shorter than those of white (851 μm; adjusted difference 95% CI, -119.8 to -8.1; P = .02) and Asian (843 μm; adjusted difference 95% CI, -117.4 to -10.8; P = .02) participants.
  
  
  CONCLUSIONS
  Although TM height is not associated with ethnicity overall, African American individuals have shorter TM heights compared with Asian and white persons. Trabecular meshwork size may play a role in ethnic differences of glaucoma risk and be a new risk factor to consider in primary open-angle glaucoma.
authors: Department of Ophthalmology, University of California, San Francisco2Department of Ophthalmology, Case Western Reserve University School of Medicine, Cleveland, Ohio.
authors: Rebecca I
authors: RI
authors: Chen
authors: Department of Ophthalmology, University of California, San Francisco3Department of Ophthalmology, Santa Casa de Misericórdia de São Paulo, São Paulo, Brazil.
authors: Diego T
authors: DT
authors: Barbosa
authors: Department of Ophthalmology, University of California, San Francisco4Department of Ophthalmology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan.
authors: Chi-Hsin
authors: CH
authors: Hsu
authors: Department of Ophthalmology, University of California, San Francisco.
authors: Travis C
authors: TC
authors: Porco
authors: Department of Ophthalmology, University of California, San Francisco.
authors: Shan C
authors: SC
authors: Lin
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005006:Ethnicity; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000208:ethnology*; D006068:Gonioscopy; D064368:Healthy Volunteers; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D009929:Organ Size; D011446:Prospective Studies; D012307:Risk Factors; D041623:Tomography, Optical Coherence; D014065:Tonometry, Ocular; D014129:Trabecular Meshwork / Q000473:pathology*