Etienne M Schönbach1, Mohamed A Ibrahim1, Xiangrong Kong1,2, Rupert W Strauss1,3,4,5,6, Beatriz Muñoz1, David G Birch7, Janet S Sunness8, Sheila K West1, Hendrik P N Scholl1,6. 1. Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States. 2. Department of Biostatistics and Epidemiology, University of Massachusetts-Amherst, Amherst, Massachusetts, United States. 3. Moorfields Eye Hospital, London, United Kingdom. 4. Department of Ophthalmology, Johannes Kepler University, Linz, Austria. 5. Department of Ophthalmology, Medical University, Graz, Austria. 6. Department of Ophthalmology, University of Basel, Basel, Switzerland. 7. Retina Foundation of the Southwest, Dallas, Texas, United States. 8. Hoover Low Vision Rehabilitation Services, Greater Baltimore Medical Center, Baltimore, Maryland, United States.
Abstract
Purpose: To compare different metrics and acquisition modes of fixation stability as a new visual function biomarker in a large cohort of patients with ABCA4-related Stargardt disease from the multicenter prospective ProgStar study. Methods: Fixation was tested during a separate fixation exam and also dynamically during a sensitivity exam, using fundus-tracking microperimetry (Nidek MP-1). Fixation data were analyzed using the bivariate contour ellipse area (BCEA), the 2/4 degree method, and the Fujii classification. Results: In a total of 235 patients, the mean BCEA was larger when measured during the sensitivity exam (418 eyes; 12.5 vs. 4.6 deg2 during the fixation task in 427 eyes). Correlations between the two tests were generally weak. Fixation stability during the sensitivity test was significantly correlated with visual acuity. Comparing the BCEA values and the corresponding Fujii categories for these eyes revealed ranges of overlap where an eye with one defined BCEA value can fall into each of the three Fujii categories. Conclusions: Patients may have limited ability to fixate over defined time periods, which leads to significant differences between shorter and longer measurements of fixation stability. The most appropriate way to use this functional biomarker appears to be using continuous metrics for fixation stability, such as the BCEA, during a macular sensitivity test.
Purpose: To compare different metrics and acquisition modes of fixation stability as a new visual function biomarker in a large cohort of patients with ABCA4-related Stargardt disease from the multicenter prospective ProgStar study. Methods: Fixation was tested during a separate fixation exam and also dynamically during a sensitivity exam, using fundus-tracking microperimetry (Nidek MP-1). Fixation data were analyzed using the bivariate contour ellipse area (BCEA), the 2/4 degree method, and the Fujii classification. Results: In a total of 235 patients, the mean BCEA was larger when measured during the sensitivity exam (418 eyes; 12.5 vs. 4.6 deg2 during the fixation task in 427 eyes). Correlations between the two tests were generally weak. Fixation stability during the sensitivity test was significantly correlated with visual acuity. Comparing the BCEA values and the corresponding Fujii categories for these eyes revealed ranges of overlap where an eye with one defined BCEA value can fall into each of the three Fujii categories. Conclusions: Patients may have limited ability to fixate over defined time periods, which leads to significant differences between shorter and longer measurements of fixation stability. The most appropriate way to use this functional biomarker appears to be using continuous metrics for fixation stability, such as the BCEA, during a macular sensitivity test.
Authors: Karl G Csaky; Praveen J Patel; Yasir J Sepah; David G Birch; Diana V Do; Michael S Ip; Robyn H Guymer; Chi D Luu; Shamika Gune; Hugh Lin; Daniela Ferrara Journal: Surv Ophthalmol Date: 2019-01-28 Impact factor: 6.048
Authors: Jacque L Duncan; Eric A Pierce; Amy M Laster; Stephen P Daiger; David G Birch; John D Ash; Alessandro Iannaccone; John G Flannery; José A Sahel; Donald J Zack; Marco A Zarbin Journal: Transl Vis Sci Technol Date: 2018-07-18 Impact factor: 3.283