title: Spectral-domain optical coherence tomography in subjects over 60 years of age, and its implications for designing clinical trials.
abstract: OBJECTIVE
  To study the variability of central retinal thickness (CRT), its concordance to the fellow eye, and the implications for designing future clinical trials using spectral-domain optical coherence tomography (SD-OCT).
  
  
  METHODS
  Cross-sectional retrospective analysis of European Genetic Database. 632 eyes of 316 subjects over 60 years of age without macular pathology were examined using SD-OCT.
  
  
  RESULTS
  Mean CRT was 280.22 µm and 281.02 µm for the right and left eyes, respectively. There was a strong concordance for all measured values between right and left eyes. Men had significantly thicker CRT than women. Variation up to 23 µm difference between both eyes was seen. To detect a change of at least 30 µm in CRT, a sample size of 90 or 176 per group is needed for a single-arm or double-arm study, respectively (α=0.05, power=0.80, no loss to follow up, assuming SD in future studies=100 µm).
  
  
  CONCLUSIONS
  Clinical trials using CRT as an endpoint are feasible in terms of sample size needed.
authors.affiliation: Department of Vitreo-Retinal Surgery, Center of Ophthalmology, University of Cologne, Germany. acaramoy@yahoo.co.uk
authors.forename: Albert
authors.initials: A
authors.lastname: Caramoy
authors.forename: Jonathan
authors.initials: J
authors.lastname: Foerster
authors.forename: Elvira
authors.initials: E
authors.lastname: Allakhiarova
authors.forename: Carel B
authors.initials: CB
authors.lastname: Hoyng
authors.forename: Katharina
authors.initials: K
authors.lastname: Dröge
authors.forename: Bernd
authors.initials: B
authors.lastname: Kirchhof
authors.forename: Sascha
authors.initials: S
authors.lastname: Fauser
mesh_terms: D000367:Age Factors; D000368:Aged; D002986:Clinical Trials as Topic / Q000379:methods*; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008268:Macular Degeneration / Q000473:pathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular; D015203:Reproducibility of Results; D012107:Research Design; D012160:Retina / Q000473:pathology*; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence / Q000379:methods* / Q000592:standards; D014792:Visual Acuity