How diabetes affects the eyes
Chronically elevated blood sugar damages the small blood vessels throughout the body, including those that supply the retina. Over time, this can cause the vessels to leak, become blocked, or stimulate abnormal new vessel growth — each of which can affect retinal function and vision.
Because these changes can develop silently over years, people with diabetes are at risk of significant retinal damage before they notice any change in their vision.
Diabetic macular oedema
Diabetic macular oedema (DMO) occurs when fluid leaks into the macula — the central part of the retina responsible for detailed vision. It is the most common cause of vision loss in people with diabetes and can occur at any stage of retinopathy.
DMO may cause blurred or distorted central vision, difficulty reading, and reduced contrast. OCT imaging is essential for detecting and monitoring oedema, including cases where vision still feels relatively good.
What a diabetic eye assessment includes
A thorough diabetic eye assessment typically involves:
- visual acuity measurement
- dilated retinal examination
- OCT imaging to assess the macula for oedema and retinal thickness
- review of previous retinal findings and comparison over time
- discussion of systemic risk factors including HbA1c, blood pressure, and lipids
Findings are documented and compared at each visit. Progression over time is one of the most important factors in deciding when and how to treat.
The role of systemic control
Alongside ophthalmic treatment, managing blood sugar, blood pressure, and cholesterol remains one of the most effective ways to slow the progression of diabetic eye disease. Ophthalmology findings are often discussed in the context of overall diabetes management, and coordination with the patient's GP or endocrinologist is sometimes relevant.