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Clinical science
Scan quality effect on glaucoma discrimination by glaucoma imaging devices
  1. K R Sung1,
  2. G Wollstein1,
  3. J S Schuman1,
  4. R A Bilonick1,
  5. H Ishikawa1,
  6. K A Townsend1,
  7. L Kagemann1,
  8. M L Gabriele1,
  9. for the Advanced Imaging in Glaucoma Study Group
  1. 1
    UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
  2. 2
  1. Correspondence to Professor Joel S Schuman, UPMC Eye Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop Street, Eye and Ear Institute, Suite 816, Pittsburgh, PA 15213, USA; schumanjs{at}


Aim: To evaluate, within ocular imaging scans of acceptable quality as determined by manufacturers’ guidelines, the effects of image quality on glaucoma discrimination capabilities.

Methods: One hundred and four healthy and 75 glaucomatous eyes from the Advanced Imaging in Glaucoma Study (AIGS) were imaged with GDx-VCC, HRT II and StratusOCT. Quality score (QS⩾8), pixel standard deviation (SD⩽50) and signal strength (SS⩾5) were used as quality parameter cut-offs, respectively. GDx nerve fibre indicator (NFI) and HRT Moorfields regression analysis (MRA) classifications and OCT mean retinal nerve fibre layer (RNFL) thickness were used as the discriminatory parameters. Logistic regression models were used to model the dichotomous clinical classification (healthy vs glaucoma) as a function of image-quality parameters and discriminatory parameters.

Results: Quality parameter covariates were statistically non-significant for GDx and HRT but had an inverse effect on OCT in predicting disease (a higher SS had a lower probability of glaucoma). Age was a significant covariate for GDx and HRT, but not OCT, while ethnicity and interaction between the image quality and the institute where scans were acquired were significant covariates in the OCT models.

Conclusion: Scan quality within the range recommended as acceptable by the manufacturer of each imaging device does not affect the glaucoma discriminating ability of GDx or HRT but does affect Stratus OCT glaucoma discrimination.

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  • KRS and GW contributed equally.

  • Presented at the International Symposium on Imaging of the Eye (ISIE) annual meeting, Fort Lauderdale, Florida, May 2006.

  • Funding Supported in part by NIH grants R01-EY013178-09, R01-EY013516-06, P30-EY008098-23 (Bethesda, Maryland), The Eye and Ear Foundation (Pittsburgh, Pennsylvania) and an unrestricted grant from Research to Prevent Blindness (New York).

  • Competing interests GW received research funding from Carl Zeiss Meditec and Optovue. JSS receives royalties for intellectual property licensed by Massachusetts Institute of Technology to Carl Zeiss Meditec. GW, JSS and HI receive royalties for intellectual property licensed by the University of Pittsburgh to Bioptigen.

  • Ethics approval Ethics approval was provided by University of Pittsburgh, University of Southern California and University of Miami.

  • Patient consent Obtained.

  • The Advanced Imaging for Glaucoma (AIG) project is a bioengineering partnership (NIH 1 R01 EY013516) sponsored by the National Eye Institute to improve quantitative imaging technologies for glaucoma diagnosis and management. Advanced Imaging for Glaucoma Study Group ( University of Miami, Bascom Palmer Eye Institute, Palm Beach, Florida: DS Greenfield, M Sehi, CD Quinn, KS Kishor; University of Pittsburgh Medical Center, UPMC Eye Center, Eye and Ear Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA: JS Schuman, G Wollstein, H Ishikawa, L Kagemann, RJ Noecker, L Camejo, E Albeiruti; University of Southern California Keck School of Medicine, Doheny Eye Institute, Los Angeles, California: D Huang (PI), R Varma, V Chopra, B Francis, F Memarzadeh, A Lu, O Tan. Steering Committee: B Francis, DS Greenfield, D Huang (Chair), JS Schuman, R Varma.

  • Provenance and peer review Not commissioned; externally peer reviewed.