Repeatability of Nidek MP-1 Fixation Measurements in Patients With Bilateral Central Field Loss

Abstract

Purpose: Visual performance in patients with bilateral central field loss is related to fixation stability. This study evaluated the repeatability of visual-fixation parameters in patients with bilateral central field loss, measured with the MP-1 microperimeter for fixation durations on the order of 15 to 30 seconds.

Methods: Bivariate contour ellipse area (BCEA), and the eccentricity and meridian of the preferred retinal locus (PRL) were determined in 56 eyes of 56 patients, sampled at two investigational sites. Repeatability and agreement were assessed by estimating 95% limits of agreement for each parameter from two fixation examinations conducted on the same day.

Results: The 95% confidence intervals (CI) for log BCEA and for PRL eccentricity and meridian were ±0.67 log deg2, ±2.0°, and ±65.9°, respectively. Each CI decreased substantially if a small number of outlying data points were excluded. For all parameters, the mean difference between the two fixation examinations was close to zero.

Conclusions: For most patients with bilateral central field loss, the repeatability of estimated BCEA and PRL eccentricity and meridian is good. When repeated estimates of fixation parameters do not agree, the absence of a well-developed PRL or the use of multiple PRLs may be suspected.

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Citation

Copyright 2015 Investigative Ophthalmology & Visual Science. Recommended citation: Bedell, Harold E., Joshua D. Pratt, Arunkumar Krishnan, Eli Kisilevsky, Taylor A. Brin, Esther G. González, Martin J. Steinbach, and Luminita Tarita-Nistor. "Repeatability of Nidek MP-1 Fixation Measurements in Patients With Bilateral Central Field LossRepeatability of Visual-Fixation Parameters." Investigative ophthalmology & visual science 56, no. 4 (2015): 2624-2630. doi: 10.1167/iovs.15-16511. URL: http://iovs.arvojournals.org/article.aspx?articleid=2281671. Reproduced in accordance with licensing terms and with author permission.