P ERSPECTIVE The Value of Tests in the Diagnosis and Management of Glaucoma MARC F. LIEBERMAN, NATHAN G. CONGDON, AND MINGGUANG HE ● PURPOSE: 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. ● DESIGN: Perspective. ● METHODS: Selected articles from primary and second- ary sources were reviewed and interpreted in the context of the authors’ clinical and research experience, influ- enced by our perspectives on the tasks of reducing the global problem of irreversible blindness caused by glau- coma. 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 detec- tion of structural changes of little functional conse- quence; 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 histori- cally what we are testing. These multiple factors should be considered in the elaboration of priorities for the development and application of tests in glaucoma. (Am J Ophthalmol 2011;152:889 – 899. © 2011 by Elsevier Inc. All rights reserved.) T HIS ARTICLE EXPLORES THE NONECONOMIC VALUE of glaucoma testing from the perspective of reducing the global problem of blindness caused by a prevent- able disease. The important enterprise of medical econo- mists who define value as “health outcomes achieved per dollar spent” 1 has never addressed the issue of glaucoma testing directly. 2–6 For us the question of a test’s value revolves around 3 questions: In what context? What kind of value? For whom? To address the value of different tests, we identify 4 major contexts for considering the disease of glaucoma. A fundamental context concerns whether we are ad- dressing structural or functional matters. Spaeth 7 has emphasized the distinction between the biological defi- nition of “glaucoma”—the characteristics of optic nerve damage by which the disease process is structurally mani- fested—and the functional outcome: how glaucoma causes human affliction and disability. The scientific rigor re- quired to discriminate pathophysiological mechanisms and demonstrate the effectiveness of interventions emphasizes the value of precise understanding; the urgency to arrest the scourge of glaucomatous blindness accentuates the value of relieving suffering. The different emphases of these 2 values are reflected in a second major context: the manner in which socioeco- nomic resources for glaucoma care are globally mobilized, in terms of equipment and trained personnel, infrastruc- ture, and the political will to provide health services. In resource-poor communities, preventing functional vision impairment is paramount; here the primary value of tests is for the efficient diagnosis of potentially blinding glaucoma. In resource-abundant settings, continuous care for the patients in various stages of the disease spectrum requires technologies whose value lies in early detection and sensitive monitoring of disease progression and response to therapy. It should be remembered that such loci of re- source-abundant and resource-poor ophthalmic capacities do not necessarily correspond to outdated locutions of “first- and third-world” locations, but may be geographi- cally congruent. 8,9 Moreover, shifting economic realities over time may well affect the sustainability of resources in currently “abundant” communities. The third context for understanding the value of testing in glaucoma lies in reconceptualizing the disease, and Accepted for publication Jun 24, 2011. From the Department of Ophthalmology, University of California, San Francisco (M.F.L.), San Francisco, California; and Zhongshan Ophthal- mic Center - Division of Preventive Ophthalmology and State Key Laboratory, Sun Yat Sen University (N.G.C., M.H.), Guangzhou, China. Inquiries to Marc F. Lieberman, Clinical Professor Ophthalmology, 1515 Scott St - #2, San Francisco, CA 94115; e-mail: sfdrmarc@ gmail.com © 2011 BY ELSEVIER INC.ALL RIGHTS RESERVED. 0002-9394/$36.00 889 doi:10.1016/j.ajo.2011.06.029