title: The Pattern of Visual Fixation Eccentricity and Instability in Optic Neuropathy and Its Spatial Relationship to Retinal Ganglion Cell Layer Thickness.
abstract: The purpose of this study was to assess whether clinically useful measures of fixation instability and eccentricity can be derived from retinal tracking data obtained during optical coherence tomography (OCT) in patients with optic neuropathy (ON) and to develop a method for relating fixation to the retinal ganglion cell complex (GCC) thickness.
  
  
  
  Twenty-nine patients with ON underwent macular volume OCT with 30 seconds of confocal scanning laser ophthalmoscope (cSLO)-based eye tracking during fixation. Kernel density estimation quantified fixation instability and fixation eccentricity from the distribution of fixation points on the retina. Preferred ganglion cell layer loci (PGCL) and their relationship to the GCC thickness map were derived, accounting for radial displacement of retinal ganglion cell soma from their corresponding cones.
  
  
  
  Fixation instability was increased in ON eyes (0.21 deg2) compared with normal eyes (0.06982 deg2; P < 0.001), and fixation eccentricity was increased in ON eyes (0.48°) compared with normal eyes (0.24°; P = 0.03). Fixation instability and eccentricity each correlated moderately with logMAR acuity and were highly predictive of central visual field loss. Twenty-six of 35 ON eyes had PGCL skewed toward local maxima of the GCC thickness map. Patients with bilateral dense central scotomas had PGCL in homonymous retinal locations with respect to the fovea.
  
  
  
  Fixation instability and eccentricity measures obtained during cSLO-OCT assess the function of perifoveal retinal elements and predict central visual field loss in patients with ON. A model relating fixation to the GCC thickness map offers a method to assess the structure-function relationship between fixation and areas of preserved GCC in patients with ON.
authors.affiliation: Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts, United States 2Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States 3Department of Ophthalmology and Visual Sciences, Universit.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Mallery
authors.affiliation: Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States.
authors.forename: Pieter
authors.initials: P
authors.lastname: Poolman
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States 4Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Thurtell
authors.affiliation: Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States 5Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, United States.
authors.forename: Jui-Kai
authors.initials: JK
authors.lastname: Wang
authors.affiliation: Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States 5Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, United States.
authors.forename: Mona K
authors.initials: MK
authors.lastname: Garvin
authors.affiliation: Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States.
authors.forename: Johannes
authors.initials: J
authors.lastname: Ledolter
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States 4Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa, United States.
authors.forename: Randy H
authors.initials: RH
authors.lastname: Kardon
mesh_terms: D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009887:Ophthalmoscopy / Q000379:methods; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000503:physiopathology*; D011446:Prospective Studies; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity