Early detection and treatment of DR and DME is essential

In the United States, 7% to 8% of the population has diabetes, and by 2045, 15% of the population is expected to be diabetic. (Image courtesy stock.adobe.com)

Glaucoma experts Rishi P. Singh, MD, and Carolyn Majcher, OD, FAAO, met recently to discuss challenges in managing diabetic retinopathy (DR) and diabetic macular edema (DME) in eye care practices.

Singh is a staff physician and president of Cleveland Clinic Florida, Martin Health in Stuart. Majcher is an associate professor and director of residency programs at Northeastern State University Oklahoma College of Optometry in Tahlequah.

The importance of sharing tips between ophthalmology and optometry practices is underscored by the data: 7% to 8% of the population in the United States has diabetes, and by 2045, 15% of the population is expected to be diabetic, Singh warned. These data, Majcher said, foretell the future of increasing eye care demands. Vision-threatening retinopathy complications, especially DME, will be of more prevalence as the leading causes of vision loss.

Singh pointed out that the biggest outcome predictor is the baseline visual acuity (VA). Earlier evaluation and treatment increased patient education. Earlier treatment can results in a better VA prognosis.

Recommendations for dilated eye examinations

Majcher advised that patients with type 1 diabetes should have annual DR screenings beginning 5 years after disease onset. Type 2 diabetes requires prompt examinations at diagnosis and yearly, because these patients have had diabetes much longer when they are diagnosed. She also said pregnant diabetic women should be examined early in the pregnancy to identify retinopathy development/ progression.

In those without DME, mild nonproliferative DR (NPDR) can be monitored yearly, and moderate NPDR can be monitored every 6 to 9 months. With center-involved DME, follow-up should be every 3 to 6 months. Severe NPDR without DME needs a referral and monitoring every 3 months.

Diagnosis and staging

Majcher pointed out that vision-threatening complications may be present despite 20/20 VA in patients who are unaware that they have type 2 diabetes. They may present with myopic shift or retinopathy during a routine examination, gradual painless visual declines bilaterally or fluctuating vision, acute-onset monocular vision loss, increased floaters from vitreous/preretinal hemorrhages, or macular ischemia. The most common cause of vision loss is DME, which occurs at any DR stage, Majcher said.

Early fundus findings of DR include microaneurysms, intraretinal hemorrhages, cotton wool spots, and exudation. More severe stages of NPDR include intraretinal microvascular abnormalities, venous feeding, and vessel sheathing in severe retinal non-perfusion and ischemia. Proliferative diabetic retinopathy (PDR) features include preretinal neovascularization and vitreous or preretinal hemorrhages. PDR findings that include poor fixators, media opacity, significant photophobia, and a deceptively quiet fundus with mini- mal to no DR signs make staging challenging, Majcher explained.

Another hurdle is identifying patients who may progress rapidly because of long-standing disease, poor glycemic control, comorbidities, or nonadherence. Singh said patients with the highest progression risk are those with severe NPDR who will likely become proliferative within 1 to 2 years.

Imaging is invaluable in practice. Majcher believes multimodal imaging technologies, optical coherence tomography (OCT), OCT angiography (OCTA), and fluorescein angiography facilitate accurate staging and early PDR detection. Widefield and ultra-widefield imaging devices image approximately 80% of the retinal surface, capturing peripheral retinal hemorrhaging that is at greater risk of progression to proliferation.

OCT provides high-resolution, cross-sectional images of retinal layers and is most useful for detecting/classifying ME. OCTA provides high-resolution microvascular details that highlight subtle/invisible vascular abnormalities during clinical fundus examinations.

Optometry: The health care gateway

The American Optometric Association’s (AOA) 2019 clinical practice guidelines advise that PDR, ME, or severe NPDR without ME be referred to a retina specialist within 2 to 4 weeks. The AOA also recommends referral in 24 to 48 hours for those at high risk of proliferation. Mild to moderate NPDR is typically referred when ME is present.

Majcher advised referral with uncertain disease stages and prompt referral for anterior segment neovascularization. Moreover, she advises optometrists to follow up with patients to ensure they were examined by a retina specialist in light of financial barriers, relying on others for transport, and patient comorbidities.

Treatment options

Anti–vascular endothelial growth factor (VEGF) therapy can help prevent neovascular glaucoma and tube-shunt surgery, Majcher said. Anti-VEGF therapies also provide the best outcomes and safety profiles, according to Singh.

Steroids and laser photocoagulation are the second and third-line options, respectively, for NPDR and DME. Proliferative disease requires panretinal laser to treat the entire retina.

Singh believes anti-VEGF treatments may be underutilized options for DME, as they do not have the adverse effects of steroids and photocoagulation, and retreatment intervals can extend 2 to 3 months.

Faricimab (Vabysmo; Genentech), a recently approved combination of an angiopoietin-2 inhibitor and anti-VEGF drug for DME, provides good results and lower treatment burdens. Seventy-five percent to 78% of patients have treatment intervals of every 12 weeks or beyond at 2 years after receiving those drugs. The 8-mg dose of aflibercept (Eylea; Regeneron Pharmaceuticals, Inc), an investigational product that Singh is anticipating, offers an improved treatment burden vs the 2-mg dose.

The Future

Tyrosine kinase inhibitors are currently being studied in age-related macular degeneration and can easily be transitioned to the DME population, Singh noted. This technology should also increase the treatment intervals.

Photobiomodulation, a light-based therapy, is being tested and improved in Europe for DR and DME. Pan-VEGF inhibition also may help control patients and reduce fluid over time.

Singh said home OCT will be a future technology that will decrease office visits, monitor severe distortion, and transfer images to the office. Other potential innovations are intraoperative surgical maneuvers that can assist outcomes for patients, according to Singh. “It is exciting to see all this coming together,” he said

Editor’s note: Reader feedback is the most powerful tool in our arsenal as we prepare content. We want to hear from you. Help shape the content by telling us what you would like to know about this topic in a follow-up article. Send us an email and let us know.

Rishi P. Singh, MD
P: 772-287-5200
Singh is president of the Cleveland Clinic Florida, Martin Health North and South hospitals in Martin County.