Retina and macula · 06
Diabetic retinopathy
Often silent early · needs regular dilated fundus exams
Last reviewed: 2026-10-03 · 潘家健醫生
Key points
- Diabetes can damage the retina; early disease can be silent — do not wait until you “cannot see.”
- Follow an ophthalmologist’s schedule for dilated exams; the interval depends on stage.
- A sudden increase in floaters without a curtain or sudden blindness: same-day dilated exam when possible.
- A curtain, a blocking shadow or sudden vision drop: go to A&E now.
What it is
Long-term high blood sugar damages retinal capillaries: leakage, macular oedema, ischaemia and new vessels, which can bleed or pull the retina off. Early disease can be silent. This is an ocular complication of endocrine disease and needs a registered doctor coordinating medical and eye care.
Symptoms
- Early disease can be silent
- Later: blur, a shower of floaters, a shadow, drop in central vision
A sudden increase in floaters without a curtain or sudden blindness: dilated fundus exam the same day if possible. A curtain, a dark shadow or a sudden vision drop: go to A&E now. Early disease can be silent — do not wait until you cannot see.
What a doctor may discuss
- Sugar, blood pressure and lipids are followed by the medical team; ophthalmology does the fundus exams and treats eye complications
- Trials such as UKPDS show more intensive glucose control is linked with lower risk of microvascular complications (including retinopathy). Literature often reports relative risk reduction; absolute risk reduction depends on baseline risk and is not a percentage you can paste onto yourself. Glucose targets are set by the medical team; ophthalmology does the fundus exams.
- Dilated fundus exams at intervals the ophthalmologist sets — not a fixed “see you next year on this date” for every person
- Diabetic macular oedema: an ophthalmologist may consider intravitreal injection and related care — not self-medication. Education figures on anti-VEGF class versus laser alone are on the intravitreal anti-VEGF topic — not personal prognosis or a brand comparison
- If a doctor arranges an injection, the order of the day is on The day of an intravitreal anti-VEGF injection. This page does not treat scatter laser for proliferative disease as the same thing.
- Intravitreal anti-VEGF, laser or surgery as classes of options when indicated
Related public education video (HKOS)
Video source: Hong Kong Ophthalmological Society (HKOS) “Eyes Decoded” YouTube (public education)
This site is not affiliated with, and is not the same organisation as, the Hong Kong Ophthalmological Society (HKOS).
Selected public references (not a full bibliography)
These are the public studies this page draws on. PMID links go to PubMed (US National Library of Medicine) so you can check them. Figures are from those studies — not your prognosis and not a clinic success rate. Links are not a shop.
- UK Prospective Diabetes Study (UKPDS) Group Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet. 1998;352(9131):837-853. PMID 9742976較積極血糖控制與較低微血管併發症（含視網膜病變）風險有關；公開摘要常強調相對風險下降，絕對下降視基線。內科跟進血糖；眼科做眼底。數字不是你的個人預後。
This is general medical information, not a diagnosis, and cannot replace an in-person consultation with a registered ophthalmologist, refraction, or a dilated fundus exam. It is not advice to use any medicine or undergo any procedure. Medicines (including off-label use), laser or surgery must be decided by a registered doctor after examination, according to indications and Hong Kong registration. Figures from the literature are published averages, not any clinic’s results. This site does not book, prescribe or refer. Do not change treatment on your own.