Rod function in diabetic patients without and with early diabetic retinopathy



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.


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).


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).


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.

Eur J Ophthalmol 2016; 26(5): 418 - 424




Evelyn Longhin, Alma P. Tormene, Elena Olivato, Enrica Convento, Stela Vujosevic, Elisabetta Pilotto, Olympia Kotsafti, Edoardo Midena

Article History


Financial support: This study was supported by a grant from the 7th Framework Programme (EUROCONDOR. FP7-278040). The scientific contribution by G.B. Bietti Foundation researchers was supported by Fondazione Roma and the Italian Ministry of Health.
Conflict of interest: None of the authors has conflict of interest with this submission.

This article is available as full text PDF.

  • If you are a Subscriber, please log in now.

  • Article price: Eur 36,00
  • You will be granted access to the article for 72 hours and you will be able to download any format (PDF or ePUB). The article will be available in your login area under "My PayPerView". You will need to register a new account (unless you already own an account with this journal), and you will be guided through our online shop. Online purchases are paid by Credit Card through PayPal.
  • If you are not a Subscriber you may:
  • Subscribe to this journal
  • Unlimited access to all our archives, 24 hour a day, every day of the week.



  •  Department of Ophthalmology, University of Padua, Padua - Italy
  •  G.B. Bietti Foundation, IRCCS, Rome - Italy

Article usage statistics

The blue line displays unique views in the time frame indicated.
The yellow line displays unique downloads.
Views and downloads are counted only once per session.

No supplementary material is available for this article.