Fixation Location and Stability Using the MP-1 Microperimeter in Stargardt Disease: ProgStar Report No. 3

Etienne M Schönbach; Mohamed A Ibrahim; Rupert W Strauss; David G Birch; Artur V Cideciyan; Gesa Astrid Hahn; Alexander Ho; Xiangrong Kong; Fadi Nasser; Janet S Sunness; Eberhart Zrenner; SriniVas R Sadda; Sheila K West; Hendrik P N Scholl; Progression of Stargardt Disease Study Group

doi:10.1016/j.oret.2016.08.009

Fixation Location and Stability Using the MP-1 Microperimeter in Stargardt Disease: ProgStar Report No. 3

Ophthalmol Retina. 2017 Jan-Feb;1(1):68-76. doi: 10.1016/j.oret.2016.08.009. Epub 2016 Oct 31.

Authors

Affiliations

¹ Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland.
² Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland; Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, United Kingdom; Department of Ophthalmology, Medical University Graz and Johannes Kepler University Linz, Linz, Austria.
³ Retina Foundation of the Southwest, Dallas, Texas.
⁴ Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
⁵ Center for Ophthalmology, Eberhard Karls Universität, Tübingen, Germany.
⁶ Doheny Eye Institute, University of California, Los Angeles, Los Angeles, California.
⁷ Greater Baltimore Medical Center, Baltimore, Maryland.
⁸ Doheny Eye Institute, University of California, Los Angeles, Los Angeles, California; David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
⁹ Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland; Department of Ophthalmology, University of Basel, Basel, Switzerland. Electronic address: [email protected].

PMID: 31047397
DOI: 10.1016/j.oret.2016.08.009

Abstract

Purpose: To determine fixation location and fixation stability in Stargardt disease (STGD1) and their association with best-corrected visual acuity (BCVA).

Design: Cross-sectional analysis within the multicenter, prospective ProgStar study.

Participants: A total of 238 patients and 440 eyes with ABCA4-related STGD1.

Methods: Patients underwent testing with the Nidek MP-1 microperimeter (Nidek Technologies Inc., Gamagōri, Japan). Fixation location was expressed as the eccentricity of the preferred retinal locus (PRL) from the anatomic fovea, fixation stability was expressed as the bivariate contour ellipse area (BCEA), and BCVA was expressed as Early Treatment Diabetic Retinopathy Study (ETDRS) letters. Linear models with generalized estimating equations were used for statistical analysis while accounting for between-eye correlations.

Main outcome measures: Fixation location and fixation stability.

Results: Median PRL eccentricity from the fovea was 6° (mean, 6.3°; range, 0°-25°) and median BCEA was 6.31°² (mean, 12.31°²; range, 0.03°²-365.63°²). Each year of later onset of symptoms of STGD1 was associated with 0.14° more central fixation location (P < 0.0001), but not with fixation stability (P = 0.53). A single linear model best described the relationship between fixation location and BCVA: 1° farther PRL eccentricity was associated with a 2.3-letter loss of BCVA (P < 0.0001). A piecewise linear model best described the relationship between fixation stability and BCVA: for a BCEA less than 2.8°², an increase in BCEA by 1°² was associated with a 10.5-letter (ETDRS) lower BCVA (P < 0.0001). For a BCEA 2.8°² or more, an increase in BCEA by 1°² was associated with a 0.036-letter (ETDRS) lower BCVA (P = 0.0234). Pearson correlation coefficients between patients' right and left eyes were 0.89 (P < 0.0001) for fixation location and 0.25 (P = 0.0006) for fixation stability. After 10 years of disease duration, 82% of patients had eccentric PRLs in both eyes.

Conclusions: We provide the first extensive database of continuous fixation parameters in STGD1 and demonstrate their association with vision. These measures allow for a more comprehensive assessment of retinal function and may serve as potential secondary outcome measures for future treatment trials for STGD1 and other macular diseases.