What is a oct scan (optical coherence tomography)?
An OCT (Optical Coherence Tomography) scan is one of the most significant advances in eye care technology. It uses light waves to take highly detailed, cross-sectional images of your retina, optic nerve, and the layers beneath the surface of the eye — areas that cannot be fully examined with a traditional eye test alone. Think of it as the eye equivalent of an MRI scan: it reveals what is happening beneath the surface.
An OCT scan can detect the earliest signs of serious conditions including glaucoma, age-related macular degeneration (AMD), diabetic retinopathy, macular holes, and vitreous detachment — often years before you notice any change in your vision. Because many of these conditions cause irreversible damage if left untreated, early detection through OCT scanning can genuinely save your sight.
Most high-street opticians now offer OCT scanning as an optional add-on to your standard eye test. While not yet routinely funded by the NHS, the scan is quick, painless, and non-invasive. A growing number of eye care professionals recommend it as a baseline scan for all patients over 25, creating a reference image that future scans can be compared against to spot even the smallest changes over time.
Who needs a oct scan (optical coherence tomography)?
- Anyone wanting the most thorough possible eye health check
- Adults over 25 as a baseline scan for future comparison
- People with a family history of glaucoma, macular degeneration, or diabetic eye disease
- Those with diabetes, high blood pressure, or other conditions affecting the eyes
- Anyone with unexplained changes in vision
- Contact lens wearers wanting to monitor corneal health
- People already diagnosed with an eye condition who need ongoing monitoring
What to expect during a oct scan (optical coherence tomography)
- 1You sit in front of the OCT machine and rest your chin on a support
- 2You look at a fixation target inside the instrument
- 3The scan takes just a few seconds per eye — there is no flash, no puff of air, and no contact with your eye
- 4The machine produces a detailed 3D image of your retina and optic nerve
- 5Your optometrist reviews the images and discusses any findings with you
- 6Results are stored digitally so future scans can be compared side by side
How much does it cost?
£10–£39 as an add-on to a standard eye test. Not routinely available on the NHS but may be used in hospital eye clinics
How often should you have this test?
Annually, or as recommended by your optometrist based on your risk profile