This site provides general eye-health education. It cannot replace individual assessment by a registered doctor, and does not offer personal diagnosis, prescriptions, bookings, sales or referrals.
If translations differ or are incomplete, the Traditional Chinese (zh-Hant) text on this site prevails.
Retinal vein or artery occlusion can suddenly affect vision; think also of blood pressure, glucose and lipids.
A sudden black-out or severe vision loss: A&E now (call 999 if you cannot travel).
Age ≥50 with temple pain, jaw claudication, shoulder-girdle pain or a curtain-like vision drop: exclude giant-cell arteritis now.
Vein occlusion without those red flags: same-day dilation and OCT when possible; severe pain / sudden drop after injection: A&E.
Arteries feed the retina; veins drain it. A blockage is a vascular event. Think blood pressure, diabetes, lipids, arrhythmia, glaucoma — and, for arterial occlusion, the carotids and giant-cell arteritis. This page does not promote any injection. If a doctor arranges an intravitreal anti-VEGF injection, the order of the day is on The day of an intravitreal anti-VEGF injection.
Vein occlusions
Branch: a patch or half-field; anti-VEGF class for macular oedema; laser if new vessels
Central: more widespread haemorrhage; watch for neovascular glaucoma over weeks to months — “100-day glaucoma” is a memory aid, not a calendar
Artery occlusions — more urgent
Sudden black-out or severe painless loss: go to A&E now. If you cannot get there: call 999. Over fifty with temple pain, jaw claudication or a curtain of vision: exclude giant-cell arteritis the same day. See the giant-cell arteritis page.
No clinic drop “opens” a freshly blocked retinal artery. Do not massage the eye or take unofficial clot drugs
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.
Hayreh SS, Zimmerman MB Central retinal artery occlusion: visual outcome. Am J Ophthalmol. 2005;140(3):376-391. PMID 16138997中央動脈阻塞視力預後差。突然失明先當急症，本頁不教自行溶栓。
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.
