title: Rod function in diabetic patients without and with early diabetic retinopathy.
abstract: OBJECTIVE
  To compare rod function among diabetic patients without and with mild nonproliferative diabetic retinopathy (DR) and healthy controls by means of scotopic microperimetry and dark-adapted electroretinography.
  
  
  METHODS
  Sixty-one diabetic patients and 30 age-matched controls (control group) underwent complete ophthalmic examination, scotopic microperimetry, and dark-adapted 0.01 electroretinography (DA-ERG).
  
  
  RESULTS
  In 32 eyes, DR was absent (no-DR group); in 29 eyes, only microaneurysms were observed (DR group). No statistically significant differences in fixation stability, fixation location, or scotopic sensitivity among the 3 groups were observed. Implicit time and amplitude of the DA-ERG b-wave of no-DR and DR groups were not different from controls. Scotopic microperimetry showed a dense scotoma centered onto the fovea in all subjects, consistent with the rod-free zone. Greater scotopic sensitivity was found in a ring located 8° from the fovea (9.33 ± 1.33 dB).
  
  
  CONCLUSIONS
  Diabetic patients without DR and with mild nonproliferative DR did not show alterations in rod-based function, as examined by microperimetry and confirmed by DA-ERG. Scotopic microperimetry measures rod-based function and offers additional information in the evaluation of the aspects of involvement of retinal cells in diabetes.
authors.affiliation: Department of Ophthalmology, University of Padua, Padua - Italy.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Longhin
authors.affiliation: Department of Ophthalmology, University of Padua, Padua - Italy.
authors.forename: Alma P
authors.initials: AP
authors.lastname: Tormene
authors.affiliation: Department of Ophthalmology, University of Padua, Padua - Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Olivato
authors.affiliation: Department of Ophthalmology, University of Padua, Padua - Italy.
authors.forename: Enrica
authors.initials: E
authors.lastname: Convento
authors.affiliation: Department of Ophthalmology, University of Padua, Padua - Italy.
authors.forename: Stela
authors.initials: S
authors.lastname: Vujosevic
authors.affiliation: Department of Ophthalmology, University of Padua, Padua - Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Pilotto
authors.affiliation: G.B. Bietti Foundation, IRCCS, Rome - Italy.
authors.forename: Olympia
authors.initials: O
authors.lastname: Kotsafti
authors.affiliation: Department of Ophthalmology, University of Padua, Padua - Italy.|G.B. Bietti Foundation, IRCCS, Rome - Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Midena
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003623:Dark Adaptation / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D004596:Electroretinography; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D055254:Night Vision / Q000502:physiology; D012160:Retina / Q000503:physiopathology; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human