title: High-Resolution Imaging of Parafoveal Cones in Different Stages of Diabetic Retinopathy Using Adaptive Optics Fundus Camera.
abstract: OBJECTIVE
  To assess cone density as a marker of early signs of retinopathy in patients with type II diabetes mellitus.
  
  
  METHODS
  An adaptive optics (AO) retinal camera (rtx1™; Imagine Eyes, Orsay, France) was used to acquire images of parafoveal cones from patients with type II diabetes mellitus with or without retinopathy and from healthy controls with no known systemic or ocular disease. Cone mosaic was captured at 0° and 2°eccentricities along the horizontal and vertical meridians. The density of the parafoveal cones was calculated within 100×100-μm squares located at 500-μm from the foveal center along the orthogonal meridians. Manual corrections of the automated counting were then performed by 2 masked graders. Cone density measurements were evaluated with ANOVA that consisted of one between-subjects factor, stage of retinopathy and the within-subject factors. The ANOVA model included a complex covariance structure to account for correlations between the levels of the within-subject factors.
  
  
  RESULTS
  Ten healthy participants (20 eyes) and 25 patients (29 eyes) with type II diabetes mellitus were recruited in the study. The mean (± standard deviation [SD]) age of the healthy participants (Control group), patients with diabetes without retinopathy (No DR group), and patients with diabetic retinopathy (DR group) was 55 ± 8, 53 ± 8, and 52 ± 9 years, respectively. The cone density was significantly lower in the moderate nonproliferative diabetic retinopathy (NPDR) and severe NPDR/proliferative DR groups compared to the Control, No DR, and mild NPDR groups (P < 0.05). No correlation was found between cone density and the level of hemoglobin A1c (HbA1c) or the duration of diabetes.
  
  
  CONCLUSIONS
  The extent of photoreceptor loss on AO imaging may correlate positively with severity of DR in patients with type II diabetes mellitus. Photoreceptor loss may be more pronounced among patients with advanced stages of DR due to higher risk of macular edema and its sequelae.
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.|Department of Ophthalmology, Assiut University, Assiut, Egypt.
authors.forename: Mohamed Kamel
authors.initials: MK
authors.lastname: Soliman
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Sadiq
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Aniruddha
authors.initials: A
authors.lastname: Agarwal
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Salman
authors.initials: S
authors.lastname: Sarwar
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Hassan
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Hanout
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Frank
authors.initials: F
authors.lastname: Graf
authors.affiliation: College of Public Health, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Robin
authors.initials: R
authors.lastname: High
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Diana V
authors.initials: DV
authors.lastname: Do
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Quan Dong
authors.initials: QD
authors.lastname: Nguyen
authors.affiliation: Ocular Imaging Reading and Research Center, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States of America.
authors.forename: Yasir J
authors.initials: YJ
authors.lastname: Sepah
mesh_terms: D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005584:Fovea Centralis / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D055095:Optics and Photonics; D010781:Photography / Q000295:instrumentation*; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence