title: Repeatability of Cone Spacing Measures in Eyes With Inherited Retinal Degenerations.
abstract: OBJECTIVE
  To determine short-term variability of adaptive optics scanning laser ophthalmoscopy (AOSLO)-derived cone spacing measures in eyes with inherited retinal degenerations (IRD) and in normal eyes.
  
  
  METHODS
  Twenty IRD patients and 10 visually normal subjects underwent AOSLO imaging at two visits separated by no more than 1 month (NCT00254605). Cone spacing was measured in multiple macular regions in each image by three independent graders. Variability of cone spacing measures between visits, between graders, and between eyes was determined and correlated with standard clinical measures.
  
  
  RESULTS
  Cone spacing was measured in 2905 regions. Interobserver agreement was high both in normal eyes and eyes with IRD (mean intraclass correlation coefficient [ICC] = 0.838 for normal and 0.892 for eyes with IRD). Cone spacing measures were closely correlated between visits (ICC > 0.869 for both study groups). Mean relative intervisit spacing difference (absolute difference in measures divided by the mean at each region) was 4.0% for normal eyes and 4.9% for eyes with IRD. Cone spacing measures from fellow eyes of the same subject showed strong agreement for all subjects (ICC > 0.85 for both study groups).
  
  
  CONCLUSIONS
  Adaptive optics scanning laser ophthalmoscopy-derived macular cone spacing measures were correlated between observers, visits, and fellow eyes of the same subject in normal eyes and in eyes with IRD. This information may help establish the role of cone spacing measures derived from images of the cone mosaic obtained with AOSLO as a sensitive biomarker for longitudinal tracking of photoreceptor loss during disease progression and in response to treatment. (ClinicalTrials.gov number, NCT00254605.).
authors.affiliation: Department of Ophthalmology University of California, San Francisco, California, United States.
authors.forename: Shiri
authors.initials: S
authors.lastname: Zayit-Soudry
authors.affiliation: Department of Ophthalmology University of California, San Francisco, California, United States 2Francis I. Proctor Foundation, Department of Ophthalmology, University of California, San Francisco, California, United States.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Sippl-Swezey
authors.affiliation: Francis I. Proctor Foundation, Department of Ophthalmology, University of California, San Francisco, California, United States.
authors.forename: Travis C
authors.initials: TC
authors.lastname: Porco
authors.affiliation: Department of Ophthalmology University of California, San Francisco, California, United States.
authors.forename: Stephanie K
authors.initials: SK
authors.lastname: Lynch
authors.affiliation: Department of Ophthalmology University of California, San Francisco, California, United States.
authors.forename: Reema
authors.initials: R
authors.lastname: Syed
authors.affiliation: Department of Ophthalmology University of California, San Francisco, California, United States.
authors.forename: Kavitha
authors.initials: K
authors.lastname: Ratnam
authors.affiliation: Department of Ophthalmology University of California, San Francisco, California, United States.
authors.forename: Moreno
authors.initials: M
authors.lastname: Menghini
authors.affiliation: School of Optometry and Vision Science Graduate Group, University of California, Berkeley, California, United States.
authors.forename: Austin J
authors.initials: AJ
authors.lastname: Roorda
authors.affiliation: Department of Ophthalmology University of California, San Francisco, California, United States.
authors.forename: Jacque L
authors.initials: JL
authors.lastname: Duncan
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009887:Ophthalmoscopy / Q000379:methods; D055095:Optics and Photonics / Q000379:methods; D011446:Prospective Studies; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology*; D012162:Retinal Degeneration / Q000473:pathology*; D055815:Young Adult