Dilated fundus examination
Screening for DR is a critical element for early intervention and reducing the risk of visual impairment. The first step begins with a comprehensive dilated examination.
Because diabetes may affect any tissue in the eye, testing includes but is not limited to:
• Best-corrected visual acuity assessment
• Pupillary testing
• Extra-ocular motility assessment
• Evaluation of confrontation fields
• Refractive manifestations evaluation
• Slit-lamp assessment
• Dilated fundus examination
Regular comprehensive eye examinations with dilation can also lead to the detection of undiagnosed diabetes. Complications of diabetes include a host of ocular manifestations that go beyond DR, including but not limited to:
• Early onset of cataracts
• Other vascular retinopathies
• Anterior ischemic optic neuropathy
• Ocular surface disease
• Diabetic papillopathy
In its early stages, DR is asymptomatic, which is why it is important for all diabetic patients to receive yearly dilated fundus examinations as recommended by the American Diabetes Association.5 Fundus photography, particularly widefield capabilities such as Optos, is often used to document the presence of any signs related to DR. These baseline images may be used to further document changes and progression and help determine whether a patient has DR and needs consultation with a retinal specialist.
Ultra-widefield imaging, fluorescein angiography
With the advent of ultra-widefield imaging, we can identify DR in the periphery of diabetic patients, which is a critical aspect of the examination. Hemorrhagic changes in the mid-periphery may be associated with further progression. DR is often under classified, and while fundus photography of the posterior pole may appear to be normal, the periphery can show numerous hemorrhaging. Ultra-widefield imaging may lead to a more accurate classification of the disease.6
Ultra-widefield fluorescein angiography (UWFA) (Optos) reveals more retinal vascular pathology in patients with DR, which may alter the classification of DR and influence treatment.6 UWFA is commonly implemented in cases categorized as NPDR. Such patients may show only moderate DR in the posterior pole, while the periphery reveals further findings of neovascularization. UWFA may also help reveal areas of non-perfusion, which can guide laser treatment, especially in cases of DME that may not be responding well to therapy. UWFA’s assessment of areas of non-perfusion may lead to identification of early signs of complications, such as neovascularization, which allows closer follow up and prompt treatment.
The presence of neovascularization, with or without vitreous hemorrhage, warrants prompt referral to a retina specialist. Established treatment options include pan-retinal photocoagulation (PRP) and/or anti-VEGF intravitreal injections to help incite regression of neovascular fronds.4,7
Recently, a large randomized control trial by the Diabetic Retinopathy Clinical Research Network revealed non-inferiority of monthly anti-VEGF injections to PRP.8 In today’s practice, the decision to pursue one modality over another is tailored to the individual patient because anti-VEGF injections, although extremely effective, require excellent patient follow-up to ensure adequate long term control of disease.