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T. L. Maddess, A. C. James, C. F. Carle, M. Kolic, X.-L. Goh; Higher Resolution Pupillographic Multifocal Visual Field Assessment. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1099.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate 4 variants of multifocal pupillographic perimetry in glaucoma. Our previous studies have used 24 test regions per eye, here 40 regions per eye were used.
We tested 20 normal and 20 glaucoma subjects, that were tightly age and sex matched. Glaucoma patients had moderate to severe fields in at least one eye. All subjects were examined with HFA achromatic, SWAP and Matrix 24-2 perimetry, Stratus OCT, slit lamp and tonometry. Informed written consent was obtained from all subjects under ANU ethics approval 238/04. Multifocal stimuli were presented concurrently to both eyes with a dartboard layout, having 40 independent test regions/eye extending to 30 deg. eccentricity (Fig). Four stimulus variants were examined in which stimuli were presented at 1/s, 1/4s, or 1/16s per region and either flickered at 20 Hz for 100 ms, or had a single 33 ms pulse. Recording duration was 4 minutes, divided into 8 segments of 30s. Pupil diameter was monitored by video cameras under infrared illumination. Data from fixation losses and blinks was automatically excluded. Up to 15% data loss from blinks and fixation losses were permitted by our regressive analysis method, which produced error estimates for each region. Measures of field loss examined the N worst amplitudes, areas under the response, delays, or pairwise linear combinations of those.
Discriminant functions including response amplitude, or area, and time to peak had area under ROC curves (AUCs) of 0.89 to 0.93 for the short pulse, 1/s, stimulus. The very slow stimulus had the worst diagnostic performance. Whichever of the direct or consensual responses gave the lowest median error was used, hence only one pupil need function.
Including more test regions provided AUCs of up to 0.93. The method eliminates problems associated with false positive and negative errors, and fixation losses found in conventional perimetry, all of which effectively lower sensitivity and specificity. Having 40 regions per eye may improve the scope for detecting clusters of damage.
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