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M.S. Kook, D.–S. Kim, J. Choi, J.–U. Hwang, H.–S. Cho; Screening Ability of the Frequency Doubling Technology Algorithm in the Detection of Normal–Tension Glaucoma With Localized Visual Field Defect . Invest. Ophthalmol. Vis. Sci. 2005;46(13):1301.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:To investigate the ability of the Frequency Doubling Technology (FDT) C20–1 screening algorithm to detect glaucoma in the eyes with normal–tension glaucoma (NTG). Methods: 45 consecutive NTG eyes from 42 patients with localized hemifield defect based on Humphrey field analyzer (HFA, Zeiss–Humphrey, Dublin, CA, USA) 24–2 glaucoma hemifield test underwent FDT C20–1 screening test. Forty–five normal eyes from 45 subjects served as control group. We used various algorithms for the FDT to calculate sensitivity and specificity measures. Likelihood ratios for a positive FDT test were also calculated. Results: Our algorithm using FDT C20–1 screening test showed best sensitivity (75.6%, 34/45 eyes) and specificity (93.3%, 42/45 eyes). Likelihood ratio for a positive FDT test with intact hemifield was 0.124 (P>0.05) and that with defective hemifield 49.8 (P<0.05). FDT screening test time in NTG patients were significantly longer than that in control group (P <0.05). A positive correlation existed between the FDT algorithm score and the HFA indices (r=.392, r=.388, respectively P<0.05). There was no difference between NTG patients and control group on FDT screening test of unaffected hemifield of HFA. Areas under the receiver–operating–characteristic curves of FDT algorithm score and test time for the detection of glaucoma were 0.864 and 0.750, respectively. Conclusions: FDT C20–1algorithm may provide a reasonable screening capability in the detection of NTG with localized visual field defect. However, it may not be as sensitive as in the eyes with high–tension glaucoma.
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