title: A Global Shape Index to Characterize Anterior Lamina Cribrosa Morphology and Its Determinants in Healthy Indian Eyes.
abstract: OBJECTIVE
  Lamina cribrosa (LC) morphology could be implicated in the progression of glaucoma. To date, no established, quantifiable parameter to assess LC shape in vivo exists. We aim to introduce a new global shape index for the anterior LC (LC-GSI) and to identify associations with ocular factors in a healthy Indian population.
  
  
  METHODS
  Optical coherence tomography (OCT) scans of the optic nerve head (ONH) were performed on 162 healthy subjects. Optic nerve head structures were delineated and a geometric characterization of anterior LC morphology was obtained by measuring curvature along 180 LC cross sections and representing it as LC-GSI ranging from -1 to +1. Lamina cribrosa depth and curvature were also reported. Linear regression was used to identify factors associated with LC morphology.
  
  
  RESULTS
  The typical healthy LC had a saddle rut-like appearance, with a central ridge visible in superior-inferior cross sections. A more prominent central ridge (larger LC-GSI) was associated with shorter axial length (P < 0.001), smaller Bruch's membrane opening (BMO) area (P = 0.020), smaller vertical cup-to-disc ratio (VCDR) (P = 0.007), and larger minimum rim width (BMO-MRW) (P = 0.001). A deeper LC was associated with male sex (P < 0.001), shorter axial length (P = 0.003), larger VCDR (P < 0.001), and smaller BMO-MRW (P = 0.002). Age and IOP were not significantly associated with LC morphology in healthy eyes.
  
  
  CONCLUSIONS
  The LC-GSI is a single index that quantifies overall LC shape in an intuitive way. Ocular determinants of LC-GSI in healthy eyes included risk factors for glaucoma (axial length, VCDR, and BMO-MRW), highlighting the potential role of LC morphological characterization in the diagnosis and monitoring of glaucoma.
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
authors.forename: Sri Gowtham
authors.initials: SG
authors.lastname: Thakku
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 2Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Yih-Chung
authors.initials: YC
authors.lastname: Tham
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 2Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 3Duke-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Mani
authors.initials: M
authors.lastname: Baskaran
authors.affiliation: University of French Polynesia, Tahiti, French Polynesia.
authors.forename: Jean-Martial
authors.initials: JM
authors.lastname: Mari
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 5National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital National Health Service Foundation Trust & University College London Institute of Ophtha.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Strouthidis
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 2Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 3Duke-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 2Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 3Duke-National University of Singapore Graduate Medical School, Singapore.
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Cheng
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 7Department of Biomedical Engineering, National University of Singapore, Singapore.
authors.forename: Michael J A
authors.initials: MJ
authors.lastname: Girard
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000869:Anterior Eye Segment / Q000033:anatomy & histology; D044466:Asian People; D058452:Axial Length, Eye / Q000033:anatomy & histology; D016570:Bruch Membrane / Q000033:anatomy & histology; D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000175:diagnosis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000033:anatomy & histology*; D011446:Prospective Studies; D012737:Sex Factors; D041623:Tomography, Optical Coherence / Q000379:methods