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Abstract #8620 Published in IGR 5-1
A method for detecting progression in glaucoma patients with deep, localized perimetric defects
Corallo G; Gandolfo EEuropean Journal of Ophthalmology 2003; 13: 49-56
PURPOSE: To define a method for early detection of progressive visual field loss, based on monitoring the 'healthy' component of the visual field, in glaucoma patients whose perimetric findings show the co-existence of deep scotomata and normal sensitivity areas. METHODS: The authors reviewed all the 'central 30-2 threshold tests' stored in the oldest of their Humphrey perimeters (a 640 VFA model, in use at the Glaucoma Service of the University Eye Clinic of Genoa since 1986). Only the perimetric findings of glaucoma patients with pure, deep, localized defects were collected for this study. In accordance with several inclusion criteria, the authors could select only 12 series of consecutive examinations (12 eyes of 12 patients). Each series included 12-20 examinations and the observation period ranged from six years two months to nine years four months. Some pre-defined criteria made it possible to separate the defective component of the visual field from the 'healthy' one. Then two independent 'mean deviations' were calculated, one relating to the 'healthy' area and one to the defective one. RESULTS: The mean deviation relating to the 'healthy' component of the visual field showed very little variation (0.6 to -1.3 dB) in the four series that had no increase in defects, even at the end of the observation period. However, in seven of the eight series with a tendency to worsen, there was a small inter-test increase (-2.2 to -2.6 dB). This finding anticipated the enlargement of the scotomata, confirmed by subsequent examinations. In only one series did the increase of the mean deviation related to the 'healthy' area coincide in time with the real deterioration of the visual field, rather than anticipating it, but the inter-test interval had by chance been much longer than in the other series. The mean deviation related to the defective areas always showed very large changes in all the series, caused by the high variability of thresholds inside scotomata. This was also the explanation for the large variations revealed by the 'global' mean deviation. CONCLUSIONS: Detecting progression is still one of the major problems in evaluating perimetric results. It might be easier to achieve this goal with a method for selectively monitoring light sensitivity inside the 'healthy' areas of the visual field.
Dr. G. Corallo, Department of Neurological Sciences, University Eye Clinic, Ospedale San Martino, Pad. 9, Largo Rosanna Benzi, 10, I-16132 Genova, Italy. guidocorallo@libero.it
Classification:
6.6.2 Automated (Part of: 6 Clinical examination methods > 6.6 Visual field examination and other visual function tests)
