Algorithm for interpreting the results of frequency doubling perimetry

PURPOSE: To evaluate an algorithm for the identification of glaucomatous vi sual field defects with the screening mode of frequency doubling technology . METHODS: Screening-mode frequency doubling technology and Swedish interacti ve threshold algorithm perimetry were performed on 137 of 150 consecutive p atients referred to a glaucoma specialist. We created an algorithm for the frequency doubling technology that gave increased importance to both more s evere defects and defects closer to fixation, These values were then compar ed with the results of the Swedish interactive threshold algorithm visual f ields evaluated by the glaucoma hemifield test, two masked glaucoma special ists, and a published definition of glaucomatous damage to determine sensit ivity and specificity of the frequency doubling technology screening mode f or detecting glaucoma. RESULTS: The frequency doubling technology score obtained with our algorith m had a sensitivity of 80% or more and specificity of 93% or more irrespect ive of the criteria for defining glaucoma. Sensitivity increased to 95% in detecting moderate or severe field loss without a compromise in specificity . All subjects with normal visual fields completed the frequency doubling t echnology examination within 90 seconds. In most cases, eyes were abnormal if they had two peripheral defects or one central defect. CONCLUSIONS: Our frequency doubling technology algorithm had both high sens itivity and high specificity in detecting glaucomatous visual field defects , allowing for bilateral screening in less than 5 minutes. (C) 2000 by Else vier Science Inc. All rights reserved.