Retina and macula · O
Macular OCT: wet AMD / diabetic macular oedema / retinal vein occlusion
Central retinal thickness · fluid
Last reviewed: 2026-10-03 · 潘家健醫生
Key points
- Macular OCT quantifies change; it does not replace a dilated exam.
- Wet AMD: new distortion needs prompt care; injections are specialist decisions.
- Retinal vein occlusion also means thinking about blood pressure and systemic factors.
- Severe pain or sudden vision drop after injection: rule out endophthalmitis — A&E now.
The macula governs fine vision. Optical coherence tomography is used for quantitative comparison and does not replace a dilated fundus exam. Central retinal thickness is often about 250–300 μm in health; machines cannot be compared directly with each other.
- Intraretinal fluid (IRF): persistence often means a poorer prognosis
- Subretinal fluid (SRF): needs serial follow-up; whether it is “acceptable” is decided by the doctor for that disease
- Pigment epithelial detachment (PED): large height or shape change suggests active neovascularisation
- Hyperreflective foci: those near the fovea may relate to inflammatory activity
Wet age-related macular degeneration: new distortion needs prompt review. Smoking markedly raises risk. Whether to give an intravitreal injection, and which registered medicine to use, can only be decided by an ophthalmologist under Hong Kong labelled indications. Large-trial averages do not guarantee personal vision. The injection day is on The day of an intravitreal anti-VEGF injection. Whether to inject is still decided by an ophthalmologist after examination.
Diabetic macular oedema: systemic HbA1c and blood-pressure control matter as much as ocular treatment and need medical follow-up. Drug choice is a prescribing decision.
Retinal vein occlusion: systemic factors such as blood pressure must be checked. Central retinal thickness can be very high. Severe pain or a sharp vision drop after injection — rule out endophthalmitis and go to A&E now.
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.