Retinal Diagnostic Tests

Retinal diagnostic tests examine the retina, the light-sensitive layer at the back of the eye, along with the optic nerve and the blood vessels that supply them. They help the doctor detect disease early, confirm a diagnosis, and plan and monitor treatment. The seven tests below are used alongside optical coherence tomography (OCT), a detailed cross-section scan of the retina, which has its own page.

People with diabetes, macular degeneration, retinal vein occlusion or other retinal conditions who need regular monitoring; anyone with symptoms such as blurred vision, new floaters, flashes of light or a shadow in their vision; premature babies who need ROP screening; and people who need a retinal check before or after eye surgery. The doctor recommends tests according to your symptoms and examination findings.

Fundus photography — colour photographs of the retina, optic disc and retinal blood vessels, used to record and monitor conditions such as diabetic retinopathy and hypertensive retinopathy over time.

OCT angiography (OCTA) — shows blood flow in the fine vessels of the retina and the layer beneath it (the choroid) without an injected dye. It helps assess diabetic retinopathy, macular degeneration, retinal vascular disorders and abnormal blood vessel growth.

Fundus fluorescein angiography (FFA) — a dye is injected into a vein in the arm and photographs are taken as it passes through the retinal blood vessels, showing leakage or abnormal vessels in conditions such as diabetic retinopathy, retinal vein occlusion and macular oedema.

B-scan ultrasonography — uses sound waves to examine the inside of the eye when the retina cannot be seen clearly, for example behind a dense cataract or a vitreous haemorrhage (bleeding inside the eye). It helps detect retinal detachment.

Dilated fundus examination — drops widen the pupil so the doctor can examine the retina and optic nerve directly with magnifying instruments. It is the basis of most retinal check-ups.

Peripheral retinal examination — an indirect ophthalmoscope gives a wide view of the outer edges of the retina, to look for retinal tears, thinning (peripheral degeneration) or detachment that a standard check may miss.

ROP screening — the retina of a premature baby is examined after dilating drops to check that its blood vessels are developing normally, and repeated at intervals until development is complete. See Retinopathy of Prematurity (ROP) for more about the condition.

Most of these tests are quick and done during your clinic visit. If your pupils are dilated, your vision will be blurred and sensitive to light for a few hours, so bring someone with you and do not drive. After FFA, your skin and urine may look yellowish for a day as the dye clears — this is expected.