Optimizing the use of frequency doubling technology perimetry in community vision screenings

In recent years, Frequency Doubling Technology perimetry (FDT) has been added to traditional ocular health testing in screening for glaucoma. This study examines a number of strategies to employ FDT in an effort to determine its optimal use in large community screenings.

In Part I, 1253 persons participated in a free, community vision screening in a large metropolitan area. FDT testing was limited to those in a high-risk group, defined as individuals over age 45 and either black or having a family history of glaucoma that passed the eye health part of the screening. In Part II, a simulated screening performed at the same location examined four different strategies for utilizing FDT: (1) FDT limited to the high risk group passing eye health testing; (2) FDT on all persons passing eye health testing; (3) FDT and eye health testing on all persons; and (4) FDT on all persons, without eye health testing.

In the community screening, 1043 persons (83.2%) passed the eye health testing. 159 (15.2%) of the 1043 were in the high risk group and were tested with FDT. 19 (1.5%) of these tests resulted in failure. There were few unreliable tests (5.0%). For the simulated screening, specificity and sensitivity with 95% confidence intervals for strategies one through four were, respectively, 83.3% (64.5 to 93.7) and 77.8% (51.9 to 92.6); 80.0% (60.9 to 91.6) and 88.9% (63.9 to 98.1); 76.7% (57.3 to 89.4) and 94.4% (70.6 to 99.7); 90.0% (72.3 to 97.4) and 38.9% (18.3 to 63.9).

In the community screening, FDT performed reliably and identified abnormalities in a significant number of persons in the high-risk group passing the eye health part of the screening. However, with the exception of the poor sensitivity shown by strategy 4, results from the simulated screening did not support the usefulness of one strategy over another.