Watch Out for Diabetic Retinopathy

Diabetic retinopathy is one of several common eye diseases, but is the most common cause of vision impairment and blindness among working-age adults in the United States. From 2010 to 2050, the number of Americans with diabetic retinopathy is expected to nearly double, from 7.7 million to 14.6 million. Diabetic retinopathy occurs when diabetes affects the blood vessels in the retina (the light-sensitive tissue in the back of the eye), causing them to leak and distort vision. If not found and treated early, diabetic retinopathy can cause permanent vision loss.

Man holding hands over eyes

Stay Alert

Diabetic retinopathy may not have any symptoms in the early stages. So if you have diabetes, be sure to schedule a comprehensive dilated eye exam once a year. Diabetic retinopathy can be diagnosed and treated before you notice any vision problems.

Symptoms that could indicate that the disease has progressed to a more advanced stage include:

  • Blurry vision
  • Spots that “float” in your vision
  • Halos around lights
  • Loss of central vision
  • Loss of color vision

Anyone with type 1 or type 2 diabetes, or women who had diabetes during pregnancy (gestational diabetes), can develop diabetic retinopathy. The risk increases the longer a person has diabetes and when blood sugar, blood pressure, and cholesterol levels are hard to control.

Fruit, measuring tape, dumbbell, glucose monitoring meterHealthy eating can reduce your risk for diabetic retinopathy.

Stay on Top of It

There are simple steps you can take to keep your eyes healthy and make sure you’re seeing your best. Taking an active role in managing your diabetes is critical:

  • Make healthy eating and physical activity part of your daily routine. This can help control blood pressure, blood sugar, and cholesterol, which can reduce your risk for developing diabetic retinopathy.
  • Quit smoking or never start. Smoking increases your risk for developing many complications from diabetes, including diabetic retinopathy.
  • If you have diabetes, schedule an annual comprehensive dilated eye exam. This can help catch vision problems early.
  • Closely follow your doctor’s instructions on how often to check your blood sugar. Keep your blood sugar as close as possible to the target range your doctor recommends.
  • If you notice any changes in your vision in one or both eyes, contact an eye doctor (ophthalmologist or optometrist) right away.

Stay Positive

Although there is no cure for diabetic retinopathy, some treatments can prevent permanent vision loss. Your eye doctor may recommend laser treatment that can help shrink blood vessels, injections that can reduce swelling, or surgery. It’s important for you to go to all follow-up appointments that your doctor schedules.

If you have diabetic retinopathy, low-vision rehabilitation and aids such as magnifying glasses, large-print newspapers, and telescopic lenses can help you stay independent. Ask your eye doctor about seeing a low-vision specialist.

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Diabetic Retinopathy Risk Drops With Diet Rich in Marine PUFAs

Eating at least two weekly servings of oily fish, rich in omega-3 polyunsaturated fatty acids (PUFAs), can help middle-aged and older people with type 2 diabetes reduce their risk for diabetic retinopathy, suggests a post hoc analysis of a major diet trial.

After adjusting for factors including age, sex, and intervention group, researchers from the PREDIMED trial found that participants who were 55 years or older and consumed at least 500 mg/day of omega-3 PUFAs showed a 48% reduced risk for incident diabetic retinopathy compared with those who consumed less than 500 mg/day (hazard ratio, 0.52; P = .001).

“Higher risk reductions were observed in participants with hypertension, those with diabetes of greater than 5 years’ duration, and those treated with insulin at baseline,” according to the report from Aleix Sala-Vila, DPharm, PhD, a researcher at CIBER-Fisiopatología de la Obesidad y Nutrición, Institut d’investigacions Biomèdiques August Pi i Sunyer, in Barcelona, Spain, and colleagues, published online August 18 in JAMA Ophthalmology.

Results align with findings from experimental models and with what researchers already know about how omega-3 cells affect diabetic retinopathy, according to the group.

“It is a fact that the amount of omega-3 in our body, and therefore in our retina, can be modulated by our diet,” Dr Sala-Vila told Medscape Medical News. “A sustained consumption of two weekly servings of fatty fish will increase the levels of omega-3 in cells. This would prevent or at least counteract inflammation in our body, a key player in the onset and progression of diabetic retinopathy. Our data reinforce a notion to date only explored in animals.”

Dr Sala-Vila said it is unclear whether supplements might have the same effect as eating fish and pointed to possible doubts raise by the ORIGIN trial (N Engl J Med. 2012;367:309-318). The trial showed no reduction of cardiovascular events over 6 years for participants initially at high cardiovascular risk who took 1000 mg/day of omega-3 PUFAs in a supplement.

Authors of the current study summarize its contribution to the literature: “Our findings support the view that regular consumption of oily fish might be beneficial to delay the onset or progression of vascular diseases in arterial beds other than the coronary and cerebrovascular ones.”

Study Based on PREDIMED Data

Data were analyzed from people with type 2 diabetes in PREDIMED, a nutrition intervention trial conducted in Spain that tested Mediterranean diets supplemented with extra virgin olive oil or nuts vs a low-fat control diet for primary cardiovascular prevention.
The current analysis is based on a PREDIMED subcohort of 3614 persons with type 2 diabetes at baseline; their aged ranged from 55 to 80 years. Full data were available for 3482 participants (48% men; average age, 67 years). Food intake was assessed at baseline and yearly for 6 years of follow-up using a 137-item food-frequency validated for the PREDIMED study. Then researchers interviewed participants on frequency of consumption of each food item in the past year and asked about usual portion sizes.

The main outcome was incident diabetic retinopathy requiring laser photocoagulation, vitrectomy, and/or antiangiogenic therapy. After a follow-up of an average 6 months, researchers found 69 new diabetic-retinopathy events.

Even More Benefit in United States?

In an accompanying editorial, Michael Larsen, MD, DMSc, department of ophthalmology, Rigshospitalet-Glostrup and University of Copenhagen in Glostrup, Denmark, notes that the study was conducted in Spain, primarily in large urban centers, where fish is a mealtime staple.

“Fish and nuts are already part of the food culture, available in every supermarket, cafeteria, and restaurant and in most households.” It is no surprise, he says, that 75% (2611 participants) met target omega-3 consumption levels at baseline.

He told Medscape Medical News that the potential for change in preventing diabetic retinopathy is greater in the United States, where consumption of fish and tree nuts (also high in omega-3 PUFAs) is much lower.

“If the results can be verified and if they extrapolate to the bottom stratum of the [omega-3] scale, where many of us roam, the implications for public health will be considerable,” he writes. “The potential value of a large-scale switch to a diet rich in [omega-3] fatty acids merits serious attention.”

Vitamin D deficiency may confer risk for retinopathy in diabetes

Patients with diabetic retinopathy are more likely to have lower 25-hydroxyvitamin D levels vs. healthy controls, according to a speaker here.

“Vitamin D may have a role in the pathophysiology of creating diabetic retinopathy,” Anawin Sanguankeo, MD, of the department of medicine at Bassett Medical Center in Cooperstown, New York, said during a media briefing at the AACE Scientific and Clinical Congress. “In the future, there should be studies that assess [whether] giving vitamin D to patients that have diabetes will prevent diabetic retinopathy or slow progression in patients who already have [diabetic retinopathy] compared to patients who do not have optimal vitamin D.”

Anawin Sanguankeo

Anawin Sanguankeo

Vitamin D deficiency, Sanguankeo said, has been associated with several cardiometabolic complications, including insulin secretion, metabolic syndrome and systemic diabetes progression. The role of vitamin D in the pathogenesis of diabetic retinopathy in humans remains an area of debate, though studies in rat models suggest an association, he said.

Sanguankeo, Sikarin Upala, MD, also of Bassett Medical Center, and colleagues completed a systematic review and meta-analysis of 11 observational studies conducted through July 2015, assessing the relationship between vitamin D deficiency (serum 25-(OH)D 20 ng/mL or less) and diabetic retinopathy (n = 9,350). Researchers calculated the pooled effect estimate of diabetic retinopathy, comparing patients with optimal vitamin D levels and vitamin D-deficient groups, and calculated the pooled mean difference of 25(OH)D levels between patients with diabetic retinopathy and healthy controls, using a random-effect, Mantel-Haenszel analysis.

Researchers found an association between diabetic retinopathy and vitamin D deficiency (OR = 1.27; 95% CI, 1.17-1.37). In patient subgroups, researchers also found that patients with diabetic retinopathy had lower serum 25-(OH)D levels vs. controls, with a mean difference of –2.22 ng/mL; 95% CI, –2.78 to –1.67).

“I think that evidence is strong enough to have future studies in this area,” Sanguankeo said. “Before there is a recommendation for clinicians [ to supplement with vitamin D], there should be evidence stronger than this, in randomized controlled trials or in prospective cohort studies. This is just the beginning of future studies that should be done.”

Randomized Clinical Trial Evaluating Intravitreal Ranibizumab or Saline for Vitreous Hemorrhage From Proliferative Diabetic Retinopathy.

Importance  Vascular endothelial growth factor plays a role in proliferative diabetic retinopathy (PDR). Intravitreal injection of saline has been shown potentially to lead to improved visual acuity compared with observation alone in eyes with vitreous hemorrhage. Therefore, it is important to determine if intravitreal anti–vascular endothelial growth factor can reduce vitrectomy rates (and risks associated with vitrectomy) compared with saline for vitreous hemorrhage from PDR that precludes placement or confirmation of complete panretinal photocoagulation.

Objective  To evaluate intravitreal ranibizumab compared with intravitreal saline injections on vitrectomy rates for vitreous hemorrhage from PDR.

Design  Phase 3, double-masked, randomized, multicenter clinical trial. Data reported were collected from June 2010 to March 2012 and include 16 weeks of follow-up.

Setting  Community-based and academic-based ophthalmology practices specializing in retinal diseases.

Participants  Two hundred sixty-one eyes of 261 study participants, who were at least 18 years of age with type 1 or type 2 diabetes mellitus. Study eyes had vitreous hemorrhage from PDR precluding panretinal photocoagulation completion.

Intervention  Eyes were randomly assigned to 0.5-mg intravitreal ranibizumab (n = 125) or intravitreal saline (n = 136) at baseline and 4 and 8 weeks.

Main Outcome Measure  Cumulative probability of vitrectomy within 16 weeks.

Results  Cumulative probability of vitrectomy by 16 weeks was 12% with ranibizumab vs 17% with saline (difference, 4%; 95% CI, −4% to 13%) and of complete panretinal photocoagulation without vitrectomy by 16 weeks was 44% and 31%, respectively (P = .05). The mean (SD) visual acuity improvement from baseline to 12 weeks was 22 (23) letters and 16 (31) letters, respectively (P = .04). Recurrent vitreous hemorrhage occurred within 16 weeks in 6% and 17%, respectively (P = .01). One eye developed endophthalmitis after saline injection.

Conclusions and Relevance  Overall, the 16-week vitrectomy rates were lower than expected in both groups. This study suggests little likelihood of a clinically important difference between ranibizumab and saline on the rate of vitrectomy by 16 weeks in eyes with vitreous hemorrhage from PDR. Short-term secondary outcomes including visual acuity improvement, increased panretinal photocoagulation completion rates, and reduced recurrent vitreous hemorrhage rates suggest biologic activity of ranibizumab. Long-term benefits remain unknown. Whether vitrectomy rates after saline or ranibizumab injection are different than observation alone cannot be determined from this study.


Source: JAMA