The Methodology of Visual Field Testing with Frequency Doubling Technology in the National Health and Nutrition Examination Survey, 2005–2006

Division of Health and Nutrition Examination Surveys, National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Maryland, USA.
Ophthalmic epidemiology (Impact Factor: 1.15). 12/2010; 17(6):411-21. DOI: 10.3109/09286586.2010.528575
Source: PubMed


To describe the frequency doubling technology (FDT) methodology to measure visual field loss in the National Health and Nutrition Examination Survey and to evaluate data reliability.
Participants aged 40 years and older were eligible (n = 2,529) for 2 visual field tests per eye performed with the Humphrey Matrix N-30-5 screening test. Visual field loss was determined using a 2-2-1 algorithm requiring 2 complete tests per eye, with at least 2 abnormal field results in each test, and 1 common abnormal field.
Response rate was 86.2%. Time constraints were the main reason for no exam (55.6%). Median times were: single test, 37 seconds; entire exam, 9.1 minutes. When defining reliability based on ≤ 1/3 blind spots, ≤ 1/3 false positive tests, and technician noted proper fixation, 80.1% of examined adults had 2 reliable tests for both eyes; an additional 13.4% had 2 reliable tests for 1 eye. Increasing age, decreasing visual acuity, and the presence of self-reported glaucoma resulted in decreased examination rates, increased test times, and decreased data reliability. Sensitivity and specificity to detect persons with glaucoma was 54.8% and 91.9%, respectively.
FDT is a feasible, fast, and reliable method for visual field loss screening in a population-based U.S. study, with an 86.2% response rate, median exam time ~9 minutes, and nearly 95% of examined participants having complete, reliable results in 1 or both eyes.

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    • "A large scale project used a different type of instrument, a more complex version of FDT, Matrix FDT with smaller five degree targets and with more targets, to screen over 2,000 participants forty years of age or older in the National Health and Nutrition Examination Survey. The Matrix FDT used was found to be reliable in eighty percent of those tested; with large reductions in acuity, glaucoma, and age reported to be the major contributions to unreliable tests [4]. "
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    ABSTRACT: This study was to investigate the feasibility of frequency doubling technology (FDT) visual field testing in Alzheimer's disease (AD) in order to identify early biomarkers of AD in patients already diagnosed with AD and compare the findings to participants not having Alzheimer's disease. This biomarker would be useful in a battery of tests for the early identification of those with AD. It was not the intent to correlate the visual system biomarker with severity of disease, but to determine if the biomarker was present in pass or fail screening criteria. The study showed with very strong significance that the FDT can identify biomarkers of those with AD compared to an age-matched population that does not have AD. FDT is a simple test to take and administer and has been used to screen for eye and retinal diseases such as glaucoma, retinal macular degeneration, and diabetic retinopathy. The results obtained in the FDT readout are analyzed and compared to the age normative database within the system. The FDT ability to screen for AD biomarker in the visual system was significant in those with AD compared to the controls, and the deficits were not related to any ocular pathology.
    09/2013; 2013:989583. DOI:10.1155/2013/989583

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