Abstract
Purpose: :
Neurodegeneration associated with diabetes has been demonstrated by many methods, including changes in retina thickness. Reductions in all layers of the retina have been documented in diabetic animal studies. This study tested the hypothesis that neurodegeneration can be detected in postmortem human retinas after a relatively short duration (5-10 years) of diabetes.
Methods: :
Retinas from human donors were acquired from the National Disease Research Institute. Donor demographics indicated the presence or absence of diabetes and use of insulin, age, sex, race and cause of death of the donor, and an estimate of the duration of diabetes. Donor retinas were paraffin-embedded, sagittally sectioned, stained with hematoxylin and eosin, and masked for morphometric analysis. Measurements were made centrally and peripherally to determine the thickness of each layer. Cell counts were performed in 100 micron-wide areas of the ganglion cell layer, the outer nuclear layer and the inner nuclear layer of each section.
Results: :
The average age of diabetic and non-diabetic donors was 54.9±10.8 (n=7) and 55.4±10.5 (n=12) years respectively. The average duration of diabetes was 4.2±2.6 years. The thickness of the outer nuclear layer was slightly less (13.5%) in the retinas from diabetic donors, compared with non-diabetic donors. There were no other differences in cell counts or retinal layer thicknesses.
Conclusions: :
The data suggest that the earliest retinal degeneration in diabetes may occur in the outer nuclear layer and is therefore most likely due to loss of a small population of photoreceptors.
Keywords: diabetic retinopathy • degenerations/dystrophies • photoreceptors