Diabetic Retinopathy

Diabetic retinopathy has two main forms:

• Early diabetic retinopathy (non-proliferative diabetic retinopathy, NPDR) is a common form. At this stage, new blood vessels are do not grow, but the walls of the existing retinal vessels weaken and form bulges that may leak blood or fluid. Mild NPDR may not affect vision, but it can progress to a sight-threatening disease.
• Advanced diabetic retinopathy (proliferative diabetic retinopathy, PDR) happens when blood vessels supplying blood to the retina are blocked, and is often accompanied by diabetic macular oedema. This promotes abnormal angiogenesis in the retina. These vessels can bleed into the eye, form scar tissue, cause retinal detachment, increase intraocular pressure, damage the optic nerve,and ultimately, cause vision loss. Without treatment, central vision loss can severely affect daily activities.

Regular diabetic retinopathy screening is crucial because symptoms are often not noticeable until the condition is more advanced. Early detection through routine eye exams ensures timely treatment to prevent vision loss.

Diabetic retinopathy can also cause other symptoms:

• Gradual blurring or patchy vision
• Sudden vision loss
• Redness or pain in the eye
• Eye floaters

Over time, high blood sugar blocks tiny blood vessels, cutting off blood supply. The body compensate by growing new blood vessels (angiogenesis), but these are fragile and prone to leaking. 

Comprehensive dilated eye examinations remain the best way to diagnose diabetic retinopathy. During this test, specific eye drops that help widen the pupils are first administered; this enables the doctor to examine the retina clearly. This may cause temporary blurring of vision, that resolves in a few hours. Additional diagnostic tools include:

• Fluorescein angiography: A fluorescein dye is injected into a vein; as the dye circulates through the ocular blood vessels, a special camera is used to capture images. These images can help identify broken, leaky, or closed blood vessels.
• Optical coherence tomography (OCT): Cross-sectional images of the retina are obtained. These images help the doctors ascertain the retinal thickness and detect fluid leakage into the retina.
   

Treatment is needed only if significant problems are detected. Options include:

• Laser photocoagulation, which seals leaking areas in patients with diabetic macular oedema. It usually does not restore vision but prevents further loss.
• Anti-VEGF injections deliver medications directly into the eye to reduce the growth of abnormal blood vessel and prevent leakage.
• Surgical procedures (vitrectomy), which removes scar tissue and clears blood that leaked into the eye in severe cases.

People with diabetes should seek immediate medical attention if they experience one or more of the following:

• Sudden vision changes.
• Eye pain or redness.
• Numerous floaters or flashes of light.
• Sudden loss of part of their visual field.

Several preventive steps can help lower the risk of diabetic retinopathy:

• Controlling blood sugar, cholesterol, and blood pressure.
• Consumption of diabetes medications as prescribed.
• Maintaining a healthy lifestyle: consumption of a balanced, nutritious diet and regular physical exercise.
• Routine eye examinations as recommended.

People with suspected or diagnosed diabetic retinopathy should consult an ophthalmologist, especially a retina specialist, for diagnosis and treatment. Regular monitoring by the diabetes care team (endocrinologist or diabetologist) is also important.