Peripapillary Retinal Nerve Thinning Faster in People With Diabetes

By David Douglas

August 03, 2019

NEW YORK (Reuters Health) - People with type 2 diabetes show accelerated thinning of the peripapillary retinal nerve fiber layer (pRNFL), even in the absence of diabetic retinopathy (DR), according to South Korean researchers.

"Our results suggest that the pRNFL status as well as DR status should be checked periodically," Dr. Jung Yeul Kim of Chungnam National University Hospital, in Daejeon, and colleagues write in JAMA Ophthalmology, online July 25.

The team notes that pRNFL is a reliable and important variable in various ophthalmic conditions that "can be measured easily by spectral-domain optical coherence tomography."

Their study includes pRNFL measurements from 164 eyes of 49 patients with diabetes without DR, 52 with mild to moderate nonproliferative DR and 63 healthy controls.

At baseline the mean pRNFL thickness was 96.2 um in the control group, 93.5 um in the non-DR group and 90.4 um in the DR group. Over the course of three years of follow-up, these numbers fell to 95.0, 90.3 and 86.6, respectively.

In a linear mixed model, the estimated mean pRNFL loss annually was significantly greater in the diabetic groups compared with controls. In particular, it was 2.9 times greater in the non-DR group and 3.3 times greater in the DR group.

The difference between the diabetic groups was not significant.

The rate of pRNFL loss in the control group, the researchers note, was consistent with those of previous studies, and the reduction rates in the diabetic groups "were similar to those of . . . patients with glaucoma."

"If patients with diabetes have a disease causing pRNFL reduction, including glaucoma or optic neuropathy," the team adds, "the reduction rate may be accelerated."

Dr. Elliott H. Sohn of the University of Iowa, in Iowa City, who co-wrote an accompanying editorial, told Reuters Health by email, "This study builds on the paradigm-shifting concept we purported in 2016 that diabetic retinal neurodegeneration (DRN) may manifest before clinically apparent diabetic retinopathy."

"The lingering questions," he added, "are how frequently DRN is found before clinical apparent diabetic retinopathy in humans, what is the mechanism for how this occurs, and what is the impact DRN has on visual function?"

Dr. Kim did not respond to requests for comments.


JAMA Ophthalmol 2019.