title: The value of tests in the diagnosis and management of glaucoma.
abstract: OBJECTIVE
  To assess the noneconomic value of tests used in the diagnosis and management of glaucoma, and explore the contexts and factors that determine such value.
  
  
  METHODS
  Perspective.
  
  
  METHODS
  Selected articles from primary and secondary sources were reviewed and interpreted in the context of the authors' clinical and research experience, influenced by our perspectives on the tasks of reducing the global problem of irreversible blindness caused by glaucoma. The value of any test used in glaucoma is addressed by 3 questions regarding: its contexts, its kind of value, and its implicit or explicit benefits.
  
  
  RESULTS
  Tonometry, slit-lamp gonioscopy, and optic disc evaluation remain the foundation of clinic-based case finding, whether in areas of more or less abundant resources. In resource-poor areas, there is urgency in identifying patients at risk for severe functional loss of vision; screening strategies have proven ineffective, and efforts are hindered by the inadequate allocation of support. In resource-abundant areas, the wider spectrum of glaucoma is addressed, with emphasis on early detection of structural changes of little functional consequence; these are increasingly the focus of new and expensive technologies whose clinical value has not been established in longitudinal and population-based studies. These contrasting realities in part reflect differences among the value ascribed, often implicitly, to the tests used in glaucoma.
  
  
  CONCLUSIONS
  The value of any test is determined by 3 aspects: its context of usage; its comparative worth and to whom its benefit accrues; and how we define historically what we are testing. These multiple factors should be considered in the elaboration of priorities for the development and application of tests in glaucoma.
authors.affiliation: Department of Ophthalmology, University of California, San Francisco, USA. sfdrmarc@gmail.com
authors.forename: Marc F
authors.initials: MF
authors.lastname: Lieberman
authors.forename: Nathan G
authors.initials: NG
authors.lastname: Congdon
authors.forename: Mingguang
authors.initials: M
authors.lastname: He
mesh_terms: D001766:Blindness / Q000517:prevention & control; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis*; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D009412:Nerve Fibers / Q000473:pathology; D009898:Optic Disk / Q000473:pathology; D011237:Predictive Value of Tests; D012165:Retinal Ganglion Cells / Q000473:pathology; D014065:Tonometry, Ocular; D058609:Visual Field Tests; D014794:Visual Fields