title: Rodent Hyperglycemia-Induced Inner Retinal Deficits are Mirrored in Human Diabetes.
abstract: OBJECTIVE
  To evaluate the utility of low luminance stimuli to functionally probe inner retinal rod pathways in the context of diabetes mellitus in both rat and human subjects.
  
  
  METHODS
  Inner retinal dysfunction was assessed using oscillatory potential (OP) delays in diabetic rats. Scotopic electroretinograms (ERGs) in response to a series of increasing flash luminances were recorded from streptozotocin (STZ)-treated and control Sprague-Dawley rats after 7, 14, 20, and 29 weeks of hyperglycemia. We then evaluated OP delays in human diabetic subjects with (DR) and without (DM) diabetic retinopathy using the International Society for Clinical Electrophysiology in Vision (ISCEV) standard scotopic protocol and two additional dim test flashes.
  
  
  RESULTS
  Beginning 7 weeks after STZ, OP implicit times in diabetic rats were progressively delayed in response to dim, but not bright stimuli. In many diabetic subjects the standard ISCEV dim flash failed to illicit measureable OPs. However, OPs became measurable using a brighter, nonstandard dim flash (Test Flash 1, -1.43 log cd s/m2), and exhibited prolonged implicit times in the DM group compared with control subjects (CTRL).
  
  
  CONCLUSIONS
  Delays in scotopic OP implicit times are an early response to hyperglycemia in diabetic rats. A similar, inner retinal, rod-driven response was detected in diabetic human subjects without diabetic retinopathy, only when a nonstandard ISCEV flash intensity was employed during ERG testing.
  
  
  CONCLUSIONS
  The addition of a dim stimulus to standard ISCEV flashes with assessment of OP latency during ERG testing may provide a detection method for early retinal dysfunction in diabetic patients.
authors: Rehab R&D Center of Excellence, Veterans Affairs Medical Center, Decatur, GA ; Department of Ophthalmology, Emory University, Atlanta, GA ; Neuroscience Program, Emory University, Atlanta, GA.
authors: Machelle T
authors: MT
authors: Pardue
authors: Rehab R&D Center of Excellence, Veterans Affairs Medical Center, Decatur, GA ; Department of Ophthalmology, Emory University, Atlanta, GA.
authors: Claire S
authors: CS
authors: Barnes
authors: Rehab R&D Center of Excellence, Veterans Affairs Medical Center, Decatur, GA ; Department of Ophthalmology, Emory University, Atlanta, GA.
authors: Moon K
authors: MK
authors: Kim
authors: Neuroscience Program, Emory University, Atlanta, GA.
authors: Moe H
authors: MH
authors: Aung
authors: Rehab R&D Center of Excellence, Veterans Affairs Medical Center, Decatur, GA.
authors: Raj
authors: R
authors: Amarnath
authors: Medical Service, Veterans Affairs Medical Center, Decatur, GA ; Division of Endocrinology, Metabolism, & Lipids, Emory University, Atlanta, GA.
authors: Darin E
authors: DE
authors: Olson
authors: Medical Service, Veterans Affairs Medical Center, Decatur, GA ; Division of Endocrinology, Metabolism, & Lipids, Emory University, Atlanta, GA.
authors: Peter M
authors: PM
authors: Thulé
keywords: diabetic retinopathy; electroretinography; rod vision