The Ability of Frequency Doubling Technology to Detect Abnormality of Visual Function in Early Glaucoma

Abstract

To evaluate the ability of the Frequency Doubling Technology(FDT) threshold test in detecting abnormality of visual function in early glaucoma patients. The C-20 full threshold test of FDT was performed on 34 normal-tension glaucoma(NTG) patients and 39 primary open-angle glaucoma(POAG) patients with visual field defects limited to the upper or lower hemi-field as detected by Humphrey Field Analyzer(HFA) and on 79 normal control subjects. Optic disk findings and FDT results corresponding to the intact hemi-field were evaluated. FDT abnormalities in normal subjects were calculated as false positive rates in FDT. The sensitivity and specificity of FDT, calculated based on optic disk findings, were 75.0% and 61.1% in POAG, and 61.1% and 66.7% in NTG, respectively, while the false positive rate in normal subjects was 11.4%. FDT can detect glaucomatous functional abnormality earlier than HFA.