The results of screening frequency doubling technology perimetry in different locations of the community

Abstract

Purpose: To determine the effect of screening location on the frequency of abnormal test results with Frequency Doubling Technology (FDT) perimetry.

Design: Retrospective cross-sectional study.

Methods: The Vision Screening Outreach Project conducted FDT testing in community sites surrounding Portland, Oregon. The sites were separated into a specific location type: health care clinics, work sites, senior centers, festivals/fairs, food banks/shelters, and other locations. These locations were compared for differences in the proportion of screening failures.

Main outcome measures: Screening failure (defined as a repeatable, abnormal FDT result in either eye).

Results: There were 9052 participants from 211 locations in Oregon and Washington. On initial FDT testing, the right and left eye had abnormal results in 18% (1654/9052) and 21% (1918/9052) of participants. Of those with abnormal FDT results, approximately 30% of eyes reverted to normal on repeat testing. Overall, 13% of participants were screening failures. Screening failure was highly associated with age (P<0.001). After controlling for age, participants at senior centers (P<0.001) were most likely to be screening failures and participants at work sites (P=0.006) were least likely to be screening failures when compared with health clinics.

Conclusions: An investigator should repeat an initially abnormal FDT result when screening with FDT. Age and the location of testing influence the probability of a screening failure. Screening in senior centers is most likely to result in screening failure. However, only a randomized controlled trial can determine the true benefit of FDT screening in these locations.