title: Repeatability of Nidek MP-1 Fixation Measurements in Patients With Bilateral Central Field Loss.
abstract: OBJECTIVE
  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.
authors: College of Optometry University of Houston, Houston, Texas, United States.
authors: Harold E
authors: HE
authors: Bedell
authors: College of Optometry University of Houston, Houston, Texas, United States.
authors: Joshua D
authors: JD
authors: Pratt
authors: College of Optometry University of Houston, Houston, Texas, United States.
authors: Arunkumar
authors: A
authors: Krishnan
authors: Toronto Western Hospital, Toronto, Ontario, Canada 3University of Toronto, Toronto, Ontario, Canada.
authors: Eli
authors: E
authors: Kisilevsky
authors: Toronto Western Hospital, Toronto, Ontario, Canada 4Centre for Vision Research, York University, Toronto, Ontario, Canada.
authors: Taylor A
authors: TA
authors: Brin
authors: Toronto Western Hospital, Toronto, Ontario, Canada 4Centre for Vision Research, York University, Toronto, Ontario, Canada 5Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.
authors: Esther G
authors: EG
authors: González
authors: Toronto Western Hospital, Toronto, Ontario, Canada 4Centre for Vision Research, York University, Toronto, Ontario, Canada 5Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.
authors: Martin J
authors: MJ
authors: Steinbach
authors: Toronto Western Hospital, Toronto, Ontario, Canada.
authors: Luminita
authors: L
authors: Tarita-Nistor
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012607:Scotoma / Q000175:diagnosis* / Q000503:physiopathology; D014792:Visual Acuity; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields; D055815:Young Adult