title: Glaucoma Structural and Functional Progression in American and Korean Cohorts.
abstract: OBJECTIVE
  To compare the rate of glaucoma structural and functional progression in American and Korean cohorts.
  
  
  METHODS
  Retrospective longitudinal study.
  
  
  METHODS
  Three hundred thirteen eyes from 189 glaucoma and glaucoma suspects, followed up for an average of 38 months.
  
  
  METHODS
  All subjects were examined semiannually with visual field (VF) testing and spectral-domain optical coherence tomography. All subjects had 5 or more reliable visits.
  
  
  METHODS
  The rates of change of retinal nerve fiber layer (RNFL) thickness, cup-to-disc (C/D) ratios, and VF mean deviation (MD) were compared between the cohorts. Variables affecting the rate of change for each parameter were determined, including ethnicity, refraction, baseline age and disease severity, disease subtype (high- vs. normal-tension glaucoma), clinical diagnosis (glaucoma vs. glaucoma suspect), and the interactions between variables.
  
  
  RESULTS
  The Korean cohort predominantly demonstrated normal-tension glaucoma, whereas the American cohort predominantly demonstrated high-tension glaucoma. Cohorts had similar VF parameters at baseline, but the Korean eyes had significantly thicker mean RNFL and larger cups. Korean glaucoma eyes showed a faster thinning of mean RNFL (mean, -0.71 μm/year vs. -0.24 μm/year; P < 0.01). There were no detectable differences in the rate of change between the glaucoma cohorts for C/D ratios and VF MD and for all parameters in glaucoma suspect eyes. Different combinations of the tested variables significantly impacted the rate of change.
  
  
  CONCLUSIONS
  Ethnicity, baseline disease severity, disease subtype, and clinical diagnosis should be considered when comparing glaucoma progression studies.
authors.affiliation: UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Tigran
authors.initials: T
authors.lastname: Kostanyan
authors.affiliation: Asan Medical Center, Department of Ophthalmology, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Kyung Rim
authors.initials: KR
authors.lastname: Sung
authors.affiliation: Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania. Electronic address: schumanjs@upmc.edu.
authors.forename: Joel S
authors.initials: JS
authors.lastname: Schuman
authors.affiliation: UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Yun
authors.initials: Y
authors.lastname: Ling
authors.affiliation: UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Katie A
authors.initials: KA
authors.lastname: Lucy
authors.affiliation: UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Bilonick
authors.affiliation: UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishikawa
authors.affiliation: UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Larry
authors.initials: L
authors.lastname: Kagemann
authors.affiliation: Asan Medical Center, Department of Ophthalmology, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Jin Y
authors.initials: JY
authors.lastname: Lee
authors.affiliation: UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Gadi
authors.initials: G
authors.lastname: Wollstein
mesh_terms: D000368:Aged; D018450:Disease Progression; D005006:Ethnicity; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000145:classification / Q000175:diagnosis* / Q000208:ethnology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009798:Ocular Hypertension / Q000175:diagnosis / Q000208:ethnology; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000208:ethnology; D056910:Republic of Korea / Q000453:epidemiology; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D014481:United States / Q000453:epidemiology; D058609:Visual Field Tests; D014794:Visual Fields