Clinical Study
Eye (2006) 20, 681–687. doi:10.1038/sj.eye.6701946; published online 24 June 2005
Evaluation of the high specificity Screening Program (C-20-1) of the Frequency Doubling Technology (FDT) perimeter in clinical practice
This study was presented, in part, at the Association for Research in Vision and Ophthalmology, Fort Lauderdale, FL, USA in May 2002.
R V North1, A L Jones1, E Hunter1, J E Morgan1,2 and J M Wild1
- 1Cardiff School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
- 2Department of Ophthalmology, University Hospital of Wales, Cardiff, UK
Correspondence: RV North, Cardiff School of Optometry and Vision Sciences, Cardiff University, Redwood Building, King Edward VII Ave, Cardiff CF10 3NB, UK. Tel: +44 029 20875114; Fax: +44 029 20874859; E-mail: north@cardiff.ac.uk
Received 8 October 2004; Revised 0000; Accepted 13 April 2005; Published online 24 June 2005.
Abstract
Aims
To compare the efficacy of the high specificity Frequency Doubling Technology (FDT) Perimeter Screening Program (C-20-1) to standard threshold automated perimetry in the diagnosis of open-angle glaucoma.
Methods
A total of 100 consecutively presenting patients attending a glaucoma clinic who volunteered for the study (approximately 30% of whom were attending for an initial visit) were examined with the FDT C-20-1 Screening Program and with the Humphrey Field Analyzer (HFA) SITA Fast algorithm and Program 24-2.
Results
Of the patients, 17 were excluded due to unreliable visual field results or non-glaucomatous ocular abnormalities. In all, 10 patients were diagnosed as normal, 54 with open-angle glaucoma, eight with ocular hypertension, and 11 as glaucoma suspects. Of the 54 glaucomatous patients, 45 exhibited high-tension glaucoma and nine normal tension glaucoma. Perimetry with the HFA gave a sensitivity of 81.5% for the combined category of glaucoma and glaucoma suspect and a specificity of 83.3% for the combined category of normal and ocular hypertension. Perimetry with the FDT gave a sensitivity of 74.5% and a specificity of 85.2% compared to that of the HFA.
Conclusion
In the detection of glaucoma, Program C-20-1 of the FDT perimeter exhibits high specificity. It exhibits low sensitivity for the detection of mild loss but high sensitivity for advanced field loss relative to Program 24-2 and the SITA Fast algorithm of the HFA.
Keywords:
Frequency Doubling Technology, Humphrey Visual Field Analyzer, glaucoma, visual field loss
