title: Cone-Photoreceptor Density in Adolescents With Type 1 Diabetes.
abstract: OBJECTIVE
  Changes to retinal structure and function occur in individuals with diabetes before the onset of diabetic retinopathy. It is still unclear if these changes initially affect vascular or neural retina, or if particular retinal areas are more susceptible than others. This paper examines the distribution of cone photoreceptor density in the retina of adolescents with type 1 diabetes.
  
  
  METHODS
  This cross-sectional prospective study includes 29 adolescents and young adults with type 1 diabetes and no diabetic retinopathy and 44 control participants recruited at the Hospital for Sick Children. Adaptive-optics enhanced retinal imaging of the cone photoreceptor mosaic was performed in four quadrants at an eccentricity of ∼7° from the fovea. After image registration and averaging, cone photoreceptors were counted and photoreceptor density was calculated. Analysis of variance with repeated measures was used to assess the differences in photoreceptor density between groups.
  
  
  RESULTS
  Cone density was similar in both control participants and participants with diabetes. There was a small effect of retinal hemisphere; participants with diabetes did not show the expected radial asymmetry observed in control participants.
  
  
  CONCLUSIONS
  Cone density in the parafoveal retina is not reduced in adolescents with type 1 diabetes.
authors.affiliation: Department of Ophthalmology and Vision Sciences, The Hospital For Sick Children, Toronto, Canada 2School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada.
authors.forename: Wylie
authors.initials: W
authors.lastname: Tan
authors.affiliation: Department of Ophthalmology and Vision Sciences, The Hospital For Sick Children, Toronto, Canada.
authors.forename: Tom
authors.initials: T
authors.lastname: Wright
authors.affiliation: Department of Ophthalmology and Vision Sciences, The Hospital For Sick Children, Toronto, Canada.
authors.forename: Durgaa
authors.initials: D
authors.lastname: Rajendran
authors.affiliation: Department of Ophthalmology and Vision Sciences, The Hospital For Sick Children, Toronto, Canada.
authors.forename: Yaiza
authors.initials: Y
authors.lastname: Garcia-Sanchez
authors.affiliation: Department of Ophthalmology and Vision Sciences, The Hospital For Sick Children, Toronto, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Finkelberg
authors.affiliation: Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada.
authors.forename: Marsha
authors.initials: M
authors.lastname: Kisilak
authors.affiliation: Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada.
authors.forename: Melanie
authors.initials: M
authors.lastname: Campbell
authors.affiliation: Department of Ophthalmology and Vision Sciences, The Hospital For Sick Children, Toronto, Canada 4Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Westall
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002452:Cell Count; D002648:Child; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology*; D005260:Female; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D011446:Prospective Studies; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology*; D042262:Retinoscopy; D055815:Young Adult