Purchase this article with an account.
R. Moosavi, T.A. Ho, G.M. Verdon–Roe, I.E. Murdoch, D.F. Garway–Heath; Pilot Study to Assess the Acceptability and Reliability of Diagnostic Instruments for Glaucoma Case–Findings . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3425.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Diagnostic instruments have a potential role in case–finding for glaucoma. However, clinical studies rarely report the proportion of reliable/acceptable test results, especially in the case–finding environment. This was a pilot study to assess the performance of three diagnostic instruments in glaucoma case–finding.
115 consecutive subjects attending an optometry practice for a regular sight test were recruited over a 3–month period. Subjects were tested with the Heidelberg Retina Tomograph II (HRTII), GDx VCC and Frequency Doubling Technology (FDT) Matrix Perimeter. The following indices were assessed:
1. Acceptability of the tests, assessed by asking two questions: (a) which was most acceptable test? (b) which was the least acceptable test? The answer options were one of the three instruments or undecided.
2. Performance of the instruments, assessed by examining the proportion of reliable images or fields produced. Assessment was made according to software–based established and recognised reliability criteria:
(a) HRT II: reliable = mean pixel height standard deviation (MPHSD) <40
(b) GDx VCC: reliable = Numerical Quality Score ≥8
(c) FDT: a, reliable = fixation losses ≤20% and false–positive rate ≤15%; b, reliable = fixation losses ≤25% and false–positive rate ≤30%
62 subjects’ opinions sought for test acceptability; 115 subjects (45 male, 70 female; mean age: 66, range 50 to 93 years) recruited for instrument performance: HRT II (228 eyes tested); GDx VCC (226 eyes tested); FDT (229 eyes tested).
In this short series, the imaging device tests were found to be the most acceptable by the subjects. Test reliability, as judged by the criteria applied, was also highest with these devices, although there is no benchmark for comparing reliability between different devices. Supported by an unrestricted grant from Pfizer.
This PDF is available to Subscribers Only