Purpose: To determine the accuracy of glaucoma detection by frequency-doubling perimetry.
Methods: Stereoview optic nerve photographs, visual field examination, intraocular pressure measurements, medical and ocular history, and a screening and full threshold frequency-doubling perimetry examination were performed in a prospective study of consecutive subjects. Inclusion criteria included age of 45 years or older, absence of ocular disease other than glaucoma, cataract, or mild drusen, and Snellen visual acuity of 20/60 or better. A total of 125 eyes in 102 glaucoma subjects and 95 eyes of 95 normal subjects were included. Each eye was classified as "normal," "glaucoma," or "uncertain" by each of three ophthalmologists on the basis of all available clinical information with the exception of frequency-doubling perimetry results. Those in the glaucoma group were subclassified as having early (n = 51), moderate (n = 42), or severe (n = 32) glaucoma on the basis of automated Humphrey visual field criteria. In the glaucoma group, two eyes from a subject were allowed to be included (23 of 102 subjects) if they differed in level of damage because they were never analyzed within the same statistical analysis.
Results: Several diagnostic algorithms were evaluated. Algorithms based on the most depressed single point, pair of adjacent points, and cluster of three points performed nearly identically. For the screening test, if any abnormality was identified, specificity was 95%, whereas sensitivity was 39%, 86%, and 100% for early, moderate, and severe glaucoma, respectively. For the full threshold test, with at least one point depressed to the P < 0.5% level, specificity measured 91%, whereas sensitivity was 35%, 88%, and 100% for early, moderate, and severe glaucoma, respectively. The two global indices, mean deviation and pattern standard deviation, were also evaluated and were generally less accurate.
Conclusion: Frequency-doubling perimetry, which is rapid and easily administered, is effective at detecting moderate and severe disease and appears well suited for glaucoma screening.