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Pure neuroretinal dysfunction in diabetic retinopathy occurring prior to endothelial and vascular damage
Author(s) -
REIS A,
MATEUS C,
MELO P,
FIGUEIRA J,
CUNHAVAZ J,
CASTELOBRANCO M
Publication year - 2013
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2013.1662.x
Subject(s) - medicine , ophthalmology , diabetic retinopathy , retinal , electroretinography , diabetes mellitus , endocrinology
Purpose To search for independent neural damage in type 1 diabetic patients, in the pre‐retinopathy stage of diabetic retinopathy (DR), with preserved blood‐retinal barrier (BRB) permeability. Methods BRB permeability was objectively measured by Vitreous Fluorometry. Neuroretinal function was assessed by standard multifocal electroretinography (mfERG) and by chromatic/achromatic contrast sensitivity (CS) (CCT‐Cambridge Research Systems and Frequency Doubling Perimetry‐FDT, Zeiss), in a sample of 42 patients (age=26.6±5.3years) with preserved visual acuity (VA), divided into two groups:1.With no clinical signs of DR and normal BRB permeability (n=23eyes; VA=1.11±0.15); 2.With BRB breakdown, with no clinical signs of DR or with mild nonproliferative DR (n=61eyes; VA=1.09±0.15). These data were compared with those obtained in 25 age‐matched controls (27.4±5.8years). Non‐parametric statistical analysis was performed at a significance level of p<0.05. Results Amplitude of neurophysiological responses was significantly decreased in all eccentricity rings in both patients groups, when compared with controls (p<0.0001). Changes in implicit time were also found in cases with preserved BRB (p<0.02). Impaired CS along the main chromatic axes was observed (p<0.03) and achromatic thresholds were also different between controls and both clinical groups (p<0.004). No correlation was found between the BRB permeability and the psychophysical and electrophysiological measurements (group with preserved BRB), confirming a lesion mechanism that is independent from endothelial/vascular changes. Conclusion Retinal neuronal changes may occur in type 1 diabetes, independently of the breakdown of the BRB or onset of vasculopathy.