Yes this study is one of those elusive R-lipoic specific studies. And the results are unequivocal.
"CONCLUSIONS/INTERPRETATION: R-(+)-alpha-lipoic acid prevents microvascular damage through normalised pathways downstream of mitochondrial overproduction of ROS, and preserves pericyte coverage of retinal capillaries, which may provide additional endothelial protection."
"R-(+)-alpha-lipoic acid treatment reduced oxidative stress, normalised NFkappaB activation and angiopoietin-2 expression, and reduced vascular endothelial growth factor in the diabetic retina by 43% (p<0.0001)."
For you glasses and pocket protector types, this is the link to the full text article.
And lucky us! We have GeroNova Research to thank for developing America's only stabilized, sustained release R-Lipoic acid.