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CJ Clemens, M Kirzhner, K Holopigian, W Seiple, VC Greenstein, RE Carr; Test-retest Reliability of Psychophysical and Electrophysiological Perimetric Measures in Patients With Retinitis Pigmentosa. . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1169.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To determine the inter-visit variability of measures of central visual function in patients with retinitis pigmentosa (RP). Methods: A group of patients with RP and a group of age-similar control subjects were examined weekly for four weeks and again at three and six months (six visits total). All subjects had visual acuity of 20/25 or better and Goldmann central visual fields of at least 10 degrees (V4e). On each visit, multifocal electroretinograms (mfERG) and custom Humphrey threshold visual fields were measured. The time of day of each visit was kept constant. The mfERGs were recorded to an array of 103 scaled hexagons (46 degrees by 39 degrees; mean luminance = 100 cd/m2). Thresholds were obtained for 103 locations, corresponding to the centers of the mfERG hexagonal array. Results: The results for the patients were subtracted from the corresponding control results, yielding difference values. These difference values were used to calculate the inter-visit variability. Areas with non-measurable Humphrey thresholds and/or non-recordable mfERGs were excluded from the analysis. For the control subjects' visual field thresholds, the averaged inter-visit variability ranged from 0.0 - 0.17 log-units, and for the patients, from 0.01 - 0.70 log units. For the control subjects, mfERG amplitude inter-visit variability ranged from 0.0 - 0.28 log-units, and for patients, from 0.01 - 0.24 log-units. The control mfERG implicit time inter-visit variability ranged from 0.0 - 3.8 msec (14.0 % change) and from 0.0 to 4.5 msec (16.7% change) for the patients. There was no consistent change in any measure as a function of retinal eccentricity for either the control subjects or the patients. Conclusion: Measures of inter-visit variability are necessary when mapping the natural history of the disease or when assessing the effects of therapeutic interventions.
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