Guide · diabetes
Diabetes and your eyes: what the yearly check looks for
Diabetes damages the small vessels at the back of the eye without any symptoms until late. You’re entitled to two checks a year — the screening photograph and a full eye test — and they do different jobs. Have both.
The two checks
NHS diabetic eye screening — the photograph, usually at a clinic or a mobile unit, once a year (every two if your last two were clear). It looks for retinopathy: the leaks, bleeds and new vessels that diabetes causes in the retina. It’s excellent at that and it’s not an eye test.
The eye test — free on the NHS for anyone with diabetes. The prescription, the pressure, the lens (diabetes brings cataract earlier), and — with the OCT scan — the macula, where diabetic swelling starts. The screening photograph can miss early swelling that the OCT shows in cross-section.
What we look for
Small bleeds and leaks in the retina · swelling at the macula on the OCT · new, fragile vessels (the serious stage, referred the same week) · early cataract · glaucoma risk, which is higher with diabetes.
The blur that isn’t retinopathy
When blood sugar swings, the lens inside the eye swells and shrinks with it, and your vision blurs for days at a time. It’s not damage and it settles when the sugar does. Don’t buy glasses during a swing — the prescription will be wrong in a fortnight. We’ll say if that’s what’s happening.
What protects your eyes
Blood sugar, blood pressure and cholesterol in range; not smoking; and turning up for both checks. Retinopathy caught early is treated with laser or injections and sight is kept. Caught late, it isn’t.
The short version
- Two checks: the NHS screening photo and a full eye test — different jobs
- The eye test is free with diabetes; add the OCT for the macula
- Blur that comes and goes with your sugar isn’t damage — don’t buy glasses mid-swing
- Sugar, pressure, cholesterol, no smoking, both checks