Detection of Glaucoma Abnormalities More Accurate with Three Visual Field Tests, Rather Than Two
Three consecutive, abnormal, reliable visual field tests have greater reliability in confirming primary open-angle glaucoma abnormalities than one or two visual field tests. This is the major conclusion of a follow-up study to the Ocular Hypertension Treatment Study (OHTS) appearing in the September 2005 issue of Archives of Ophthalmology.
In the original OHTS, criterion for determination of visual field abnormality was two consecutive, abnormal, reliable visual field tests. However, follow-up research on the OHTS data revealed that nearly 86 percent of the visual field tests immediately following the first abnormal visual field test were normal. This indicated the need for additional abnormal visual field tests before a patient could be diagnosed with a glaucoma visual field abnormality.
In the present follow-up study, the Ocular Hypertension Treatment Study Group authors found that 66 percent of subsequent visual field tests were normal after two consecutive, abnormal, reliable visual field tests, but only 12 percent were normal after three consecutive, abnormal, reliable visual field tests. The OHTS protocol now requires three consecutive, abnormal, reliable visual field tests.
The authors emphasized the importance of a high degree of specificity in diagnosing primary, open-angle glaucoma, and said, "Before a physician commits an individual to a lifetime of medical treatment, he or she should have a high degree of certainty about the diagnosis."
Citation:
Keltner KL, JohnsonCA, Levine RA, Fan J, Cello KE, Kass MA,Gordon MO; for the Ocular Hypertension Treatment Study Group: Normal Visual Field Test Results Following Glaucomatous Visual Field End Points in the Ocular Hypertension Treatment Study. Arch Ophthalmol 123:1201-1206, 2005.
