A Report by the American Academy of Ophthalmology Ophthalmic Technology Assessment Committee Glaucoma Panel: Scott D. Smith, MD, MPH1; Kuldev Singh, MD, MPH2; Shan C. Lin, MD3; Philip P. Chen, MD4; Teresa C. Chen, MD5; Brian A. Francis, MD6; Henry D. Jampel, MD, MHS7
Ophthalmology, October 2013, Vol 120, 1985-1997 © 2013 by the American Academy of Ophthalmology. Click here for free access to the OTA.
Objective: To assess the published literature pertaining to the association between anterior segment imaging and gonioscopy and to determine whether such imaging aids in the diagnosis of primary angle closure (PAC).
Methods: Literature searches of the PubMed and Cochrane Library databases were last conducted on July 6, 2011. The searches yielded 371 unique citations. Members of the Ophthalmic Technology Assessment Committee Glaucoma Panel reviewed the titles and abstracts of these articles and selected 134 of possible clinical significance for further review. The panel reviewed the full text of these articles and identified 79 studies meeting the inclusion criteria, for which the panel methodologist assigned a level of evidence based on a standardized grading scheme adopted by the American Academy of Ophthalmology. Three, 70, and 6 studies were rated as providing level I, II and III evidence, respectively.
Results: Quantitative and qualitative parameters defined from ultrasound biomicroscopy (UBM), anterior segment optical coherence tomography (OCT), Scheimpflug photography, and the scanning peripheral anterior chamber depth analyzer (SPAC) demonstrate a strong association with the results of gonioscopy. There is substantial variability in the type of information obtained from each imaging method. Imaging of structures posterior to the iris is possible only with UBM. Direct imaging of the anterior chamber angle (ACA) is possible using UBM and OCT. The ability to acquire OCT images in a completely dark environment allows greater sensitivity in detecting eyes with appositional angle closure. Non-contact imaging using OCT, Scheimpflug photography or SPAC makes these modalities more attractive for large-scale PAC screening than contact imaging using UBM.
Conclusions: Although there is evidence suggesting that anterior segment imaging provides useful information in the evaluation of PAC, none of these imaging methods provides sufficient information about the ACA anatomy to be considered a substitute for gonioscopy. Longitudinal studies are needed to validate the diagnostic significance of the parameters measured by these instruments for prospectively identifying individuals at risk for PAC.
1Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
2Department of Ophthalmology, Stanford University School of Medicine, Stanford, California
3Department of Ophthalmology, University of California, San Francisco, San Francisco, California
4Department of Ophthalmology, University of Washington, Seattle, Washington
5Harvard Medical School, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Glaucoma Service, Boston, Massachusetts
6Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
7Glaucoma Center for Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland