Since 1995, Dr. Alistair Barber’s research has focused on the role of retinal neurodegeneration in vision-loss in diabetic retinopathy. This degenerative disease of the retina is a common complication of diabetes and is the leading cause of vision loss in working-age adults in the developed countries. The Barber lab was one of the first to show that diabetes increases retinal cell death by apoptosis, and went on to quantify the accelerated loss of a variety of sub-types of neurons in animal models of diabetes. The lab also identified other morphological changes in neurons, including alterations in the structure of retinal ganglion cell dendrites, and found that these changes are accompanied by deficient expression of synaptic proteins required for neurotransmitter release.

Diabetes-induced changes in morphology and synaptic protein expression in the retina are accompanied by functional deficits in vision in the animal models, including reduced acuity and contrast sensitivity, which replicates observations in humans with diabetes. Other metabolic changes within the retina that are associated with diabetes include cytokine release and activation of macro- and microglia, indicating that neuro-inflammation accompanies neurodegeneration. Together these functional deficits conspire with vascular abnormalities such as dysregulation of endothelial cell tight junction proteins, leading to increased vascular permeability and loss of the blood-retinal barrier.

This work has helped to establish neurodegeneration as an important contributing factor in diabetic retinopathy, which was previously considered primarily from the perspective of a vascular disease. Current clinical and basic research data, however, confirm that chronic neurodegeneration is an important characteristic of diabetic retinopathy in humans as well as animal models, and the neurodegeneration appears to begin simultaneously with, or even before, the first vascular lesions become evident in the retina.

In addition to his own research, Dr. Barber is associate research director for Penn State Eye Center.

Silver Fellow, Association for Research in Vision and Ophthalmology, 2019

Visiting Professor, Henan Eye Institute, 2014