What it is
Optical coherence tomography (OCT) uses harmless light waves to create detailed cross-section pictures of the retina and optic nerve at the back of the eye — similar to an ultrasound, but using light. It shows layers of the retina that cannot be seen in a routine examination, helping to detect swelling, fluid, thinning or holes.
Who it's for
People with diabetic eye disease, macular degeneration, glaucoma, macular holes or retinal vein blockages, and people who need a detailed check before or after eye surgery. It is also used to track how well treatments such as eye injections are working.
What to expect
You sit at the machine, rest your chin on a support and look at a target light for a few minutes. Nothing touches your eye. Sometimes dilating drops are used first.
Recovery
There is no recovery time. If dilating drops were used, your vision will be blurred and sensitive to light for a few hours, so do not drive yourself home.
Frequently asked questions
Is an OCT scan safe?
Yes. OCT uses light, not radiation, and nothing touches the eye.
How often will I need an OCT scan?
It depends on your condition. Your doctor will advise how often scans are needed to monitor your eyes.
Medically reviewed by Dr. Sweta Patro
