title: Subgrouping of primary angle-closure suspects based on anterior segment optical coherence tomography parameters.
abstract: OBJECTIVE
  To identify subgroups of primary angle-closure suspects (PACS) based on anterior segment optical coherence tomography (AS-OCT) and biometric parameters.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  We evaluated 243 PACS subjects in the primary group and 165 subjects in the validation group.
  
  
  METHODS
  Participants underwent gonioscopy and AS-OCT (Carl Zeiss Meditec, Dublin, CA). Customized software (Zhongshan Angle Assessment Program, Guangzhou, China) was used to measure AS-OCT parameters. An agglomerative hierarchical clustering method was first used to determine the optimum number of parameters to be included in the determination of subgroups. The best number of subgroups was then determined using Akaike Information Criterion (AIC) and Gaussian Mixture Model (GMM) methods.
  
  
  METHODS
  Subgroups of PACS.
  
  
  RESULTS
  The mean age of the subjects was 64.8 years, and 65.02% were female. After hierarchical clustering, 1 or 2 parameters from each cluster were chosen to ensure representativeness of the parameters and yet keep a minimum of redundancy. The parameters included were iris area, anterior chamber depth (ACD), anterior chamber width (ACW), and lens vault (LV). With the use of GMM, the optimal number of subgroups as given by AIC was 3. Subgroup 1 was characterized by a large iris area, subgroup 2 was characterized by a large LV and a shallow ACD, and subgroup 3 was characterized by elements of both subgroups 1 and 2. The results were replicated in a second independent group of 165 PACS subjects.
  
  
  CONCLUSIONS
  Clustering analysis identified 3 distinct subgroups of PACS subjects based on AS-OCT and biometric parameters. These findings may be relevant for understanding angle-closure pathogenesis and management.
authors.affiliation: Singapore Eye Research Institute and Singapore National Eye Center, Singapore; Duke-NUS Graduate Medical School, Singapore.
authors.forename: Monisha E
authors.initials: ME
authors.lastname: Nongpiur
authors.affiliation: Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore.
authors.forename: Tianxia
authors.initials: T
authors.lastname: Gong
authors.affiliation: Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore.
authors.forename: Hwee Kuan
authors.initials: HK
authors.lastname: Lee
authors.affiliation: Singapore Eye Research Institute and Singapore National Eye Center, Singapore.
authors.forename: Shamira A
authors.initials: SA
authors.lastname: Perera
authors.affiliation: Bioinformatics Institute, A*STAR (Agency for Science, Technology and Research), Singapore.
authors.forename: Li
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Duke-NUS Graduate Medical School, Singapore.
authors.forename: Li-Lian
authors.initials: LL
authors.lastname: Foo
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
authors.affiliation: Wilmer Eye Institute, Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: David S
authors.initials: DS
authors.lastname: Friedman
authors.affiliation: Singapore Eye Research Institute and Singapore National Eye Center, Singapore; Duke-NUS Graduate Medical School, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: aung.tin@snec.com.sg.
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
mesh_terms: D000869:Anterior Eye Segment / Q000473:pathology*; D001699:Biometry; D003430:Cross-Sectional Studies; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis*; D006068:Gonioscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011680:Pupil; D041623:Tomography, Optical Coherence