Assessment of the Student Sight Savers Program Methods for Glaucoma Screening

ABSTRACT

Purpose: To assess methods used for glaucoma screening in the Student Sight Savers Program (SSSP), an initiative of the Friends of the Congressional Glaucoma Caucus Foundation that has screened individuals for glaucoma in the United States since 2001. Methods: This was a prospective, case-control, clinic-based study (total N = 70). Patients with primary open-angle glaucoma and age- and sex-matched controls with no evidence of glaucoma or other ocular disease were evaluated with the SSSP screening method. Primary outcome measures were sensitivity, specificity, and positive predictive power for both low- and high-prevalence populations. Results: Sensitivity and specificity values of the individual tests were 48.6% and 68.6% for family history of glaucoma, 22.1% and 78.6% for intraocular pressure (IOP), and 58.1% and 98.6% for frequency doubling technology (FDT) visual field (P = 0.03, chi-square). Specificity of FDT was significantly better than IOP (P < 0.001) and the questionnaire (P < 0.01) by z-test. When analyzing the overall screening criteria (positive screen was ≥ 1 positive in the three tests), the sensitivity increased to 88.6% with reduction in specificity to 57.1%. The positive predictive power (PPP) for high-prevalence population was low for the overall screening criteria (15.4%) and highest for FDT as an individual (34.0%) or combined (41.0% to 45.3%) test. The medical student education and community awareness aspects of the program were not assessed. Conclusions: Of different methods used in the SSSP, FDT was the best single screening test, demonstrating high specificity but only moderate sensitivity. Use of multiple screening criteria resulted in slightly increased sensitivity and PPP over FDT, but decreased specificity.

Keywords: :

• Automated perimetry
• frequency doubling technology
• glaucoma
• intraocular pressure
• screening