title: Lamina cribrosa visibility using optical coherence tomography: comparison of devices and effects of image enhancement techniques.
abstract: OBJECTIVE
  To compare the visibility of the lamina cribrosa (LC) in optic disc images acquired from 60 glaucoma and 60 control subjects using three optical coherence tomography (OCT) devices, with and without enhanced depth imaging (EDI) and adaptive compensation (AC).
  
  
  METHODS
  A horizontal B-scan was acquired through the center of the disc using two spectral-domain (Spectralis and Cirrus; with and without EDI) and a swept-source (DRI) OCT. Adaptive compensation was applied post acquisition to improve image quality. To assess LC visibility, four masked observers graded the 1200 images in a randomized sequence. The anterior LC was graded from 0 to 4, the LC insertions from 0 to 2, and the posterior LC either 0 or 1. The effect of EDI, AC, glaucoma severity, and other clinical/demographic factors on LC visibility was assessed using generalized estimating equations.
  
  
  RESULTS
  The anterior LC was the most detectable feature, followed by the LC insertions. Adaptive compensation improved anterior LC visibility independent of EDI. Cirrus+EDI+AC generated the greatest anterior LC visibility grades (2.79/4). For LC insertions visibility, DRI+AC was the best method (1.10/2). Visibility of the posterior LC was consistently poor. Neither glaucoma severity nor clinical/demographic factors consistently affected LC visibility.
  
  
  CONCLUSIONS
  Adaptive compensation is superior to EDI in improving LC visibility. Visibility of the posterior LC remains poor suggesting impracticality in using LC thickness as a glaucoma biomarker.
authors.affiliation: In Vivo Biomechanics Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
authors.forename: Michaël J A
authors.initials: MJ
authors.lastname: Girard
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
authors.forename: Tin A
authors.initials: TA
authors.lastname: Tun
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
authors.forename: Rahat
authors.initials: R
authors.lastname: Husain
authors.affiliation: Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore.
authors.forename: Sanchalika
authors.initials: S
authors.lastname: Acharyya
authors.affiliation: Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore Department of Statistics and Applied Probability, National University of Singapore, Singapore.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Haaland
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore.
authors.forename: Xin
authors.initials: X
authors.lastname: Wei
authors.affiliation: Department of Medical Physics and Bioengineering, UCL, London, United Kingdom.
authors.forename: Jean M
authors.initials: JM
authors.lastname: Mari
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
authors.forename: Shamira A
authors.initials: SA
authors.lastname: Perera
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
authors.forename: Mani
authors.initials: M
authors.lastname: Baskaran
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom Discipline of Clinical Ophthalmology and Eye Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Strouthidis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology*; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000295:instrumentation*
keywords: adaptive compensation; enhanced depth imaging; glaucoma; intraocular pressure; lamina cribrosa; optical coherence tomography