title: Cone Photoreceptor Irregularity on Adaptive Optics Scanning Laser Ophthalmoscopy Correlates With Severity of Diabetic Retinopathy and Macular Edema.
abstract: To determine whether cone density, spacing, or regularity in eyes with and without diabetes (DM) as assessed by high-resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) correlates with presence of diabetes, diabetic retinopathy (DR) severity, or presence of diabetic macular edema (DME).
  
  
  
  Participants with type 1 or 2 DM and healthy controls underwent AOSLO imaging of four macular regions. Cone assessment was performed by independent graders for cone density, packing factor (PF), nearest neighbor distance (NND), and Voronoi tile area (VTA). Regularity indices (mean/SD) of NND (RI-NND) and VTA (RI-VTA) were calculated.
  
  
  
  Fifty-three eyes (53 subjects) were assessed. Mean ± SD age was 44 ± 12 years; 81% had DM (duration: 22 ± 13 years; glycated hemoglobin [HbA1c]: 8.0 ± 1.7%; DM type 1: 72%). No significant relationship was found between DM, HbA1c, or DR severity and cone density or spacing parameters. However, decreased regularity of cone arrangement in the macular quadrants was correlated with presence of DM (RI-NND: P = 0.04; RI-VTA: P = 0.04), increasing DR severity (RI-NND: P = 0.04), and presence of DME (RI-VTA: P = 0.04). Eyes with DME were associated with decreased density (P = 0.04), PF (P = 0.03), and RI-VTA (0.04).
  
  
  
  Although absolute cone density and spacing don't appear to change substantially in DM, decreased regularity of the cone arrangement is consistently associated with the presence of DM, increasing DR severity, and DME. Future AOSLO evaluation of cone regularity is warranted to determine whether these changes are correlated with, or predict, anatomic or functional deficits in patients with DM.
authors.affiliation: Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts, United States 2Department of Ophthalmology, Medical University Vienna, Vienna, Austria.
authors.forename: Jan
authors.initials: J
authors.lastname: Lammer
authors.affiliation: Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts, United States 2Department of Ophthalmology, Medical University Vienna, Vienna, Austria.
authors.forename: Sonja G
authors.initials: SG
authors.lastname: Prager
authors.affiliation: Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts, United States.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Cheney
authors.affiliation: Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts, United States 3Department of Histology and Cell Biology, Faculty of Medicine, Assiut University, Assiut, Egypt.
authors.forename: Amel
authors.initials: A
authors.lastname: Ahmed
authors.affiliation: Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts, United States 4Department of Ophthalmology, Cairo University, Cairo, Egypt.
authors.forename: Salma H
authors.initials: SH
authors.lastname: Radwan
authors.affiliation: School of Optometry, Indiana University, Bloomington, Indiana, United States.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Burns
authors.affiliation: Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts, United States 6Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Paolo S
authors.initials: PS
authors.lastname: Silva
authors.affiliation: Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts, United States 6Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Sun
mesh_terms: D000328:Adult; D000368:Aged; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D008269:Macular Edema / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy / Q000379:methods*; D055095:Optics and Photonics; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence / Q000379:methods; D014792:Visual Acuity; D055815:Young Adult