People with diabetes are much more likely to develop eye disorders and vision loss than people who don’t have the disease. According to the U.S. National Center for Health Statistics, nearly a third of Americans 45 and over with diabetes have cataracts and nearly one out of 10 have diabetic retinopathy, vision-threatening condition caused by damage to the blood vessels at the back of the eye, or retina. Other common eye problems among people with diabetes are glaucoma and macular degeneration.
But is there a difference between type 1 and type 2 diabetes when it comes to the eyes? According to a new study from researchers at the Mayo Clinic, there is. And, in what might be considered a somewhat surprising finding, it appears that young people with type 2 diabetes are more likely to experience eye troubles that those with type 1. The study appeared in JAMA Ophthalmology, a medical journal published by the American Medical Association.
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Using records spanning a 50-year period, the researchers, who were led by Brian G, Mohney, MD, of the Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, collected data on 606 people who lived in Olmsted County, Minnesota. The male-female proportion was about 50-50 and they all had been diagnosed with diabetes before turning 22 (the average age at diagnosis was 12). The incidence of type 1 diabetes was 26 per 100,000 children per year; the incidence of type 2 was 5 per 100,000. For reasons the researchers couldn’t explain, the percentage of girls was high (71.9%) in the type 2 group but not in the type 1 group (46.6%).
Youth type 2 diabetes linked to greater eye risk than type 1
The researchers reported the unforeseen results that type 2 diabetes appears to be a more substantial danger to eye health than type 1 — a finding that applied to all types of eye problems. After having diabetes for 15 years, more than half of the subjects with type 2 (52.7%) developed retinopathy but less than one out of three people with type 1 diabetes (30.6%) did. Those with type 2 diabetes were also found to be at greater risk of diabetic macular edema, “visually significant” cataracts, and the various conditions that require a type of eye surgery called pars plana vitrectomy. These conditions include large retinal tears, retinal detachment, vitreous hemorrhage, and endophthalmitis (a type of eye infection).
Age differences found in the onset of eye problems
The researchers also reported age differences in the onset of eye problems, with the type 1 participants tending to develop them in their teenage years and the type 2 participants more likely to develop them in their early 20s. Due to this finding, the researchers wrote, “This suggests that the natural history of retinopathy development among youth diagnosed with Type 2 diabetes may differ from that in youth diagnosed with Type 1 diabetes, where patients with [Type 2] may be more susceptible to developing retinopathy than those with [Type 1] despite controlling for diabetes disease duration.” It also turned out that it took a few years for eye problems to emerge: the chances of developing conditions worrisome enough to endanger vision in the first five years after diagnosis were zero in both the type 1 and type 2 groups.
The published article was accompanied by a commentary by Jennifer K. Sun, MD, of the Joslin Diabetes Center and Harvard Medical School. She pointed out that future research will need to investigate the possible role of other factors in the development of eye disease in people with diabetes — things such as body-mass index (BMI, a measure of weight relative to height), lipid levels, and high blood pressure. But, she said, the results of the new study “emphasize the need to explore potential differences between ocular outcomes in patients with Type 1 vs. Type 2 diabetes and to elucidate the mechanisms behind any differences that do exist.” The researchers themselves concluded by commenting that their findings “suggests that to prevent serious ocular complications, children with [type 2 diabetes] may require ophthalmoscopic evaluations at least as frequently as or more frequently than children with [type 1 diabetes].”
Want to learn more about keeping your eyes healthy with diabetes? Read “Diabetic Eye Exams: What to Know,” “Eating for Better Vision and Healthy Eyes,” and “Keeping Your Eyes Healthy” and watch “Diabetes and Your Eyes.”