Optical coherence tomography (OCT) is a non-invasive test that takes images of the inside of your eye, specifically your retina (the light-sensitive layer at the back of your eye). An OCT scan allows optometrists to see each layer of the retina and measure its thickness, as well as evaluate its structure and function. 

OCT scans are now a routine procedure used to help detect many different eye conditions. If you're interested in having an OCT scan and would like to know more about the procedure, this guide should help to put your mind at ease.

Are OCT scans safe?

An OCT scan is a safe procedure that involves using reflected visible light from a low-power laser to obtain images of your retina1 — the principle is similar to ultrasound, but uses light instead of sound. 

The scan is non-invasive (does not touch your eye), quick, and painless and there are no known side effects or complications. 

At Specsavers, we have two types of OCT scanners: the Heidelberg Spectralis OCT eye scanner and the Nidek Retina scan duo.3,4 You can chat to your Specsavers optometrist if you want to find out more about the scanners during your appointment. 

Is there a risk of light exposure?

In terms of light exposure, bright lights (like the sun) and blue light (from computer screens) are known to potentially cause complications to vision from prolonged exposure. OCT machines are designed to cease scanning the moment it detects too much light exposure. As such, the risk is extremely minimal. 

Can OCT scans misdiagnose?

Optometrists carry out specialist training on how to use and interpret the results from OCT scans correctly and effectively. 

In terms of OCT itself as a piece of technology, there is very minimal risk of potentially leading the optometrist to a misdiagnosis. This is due to its simple function. It takes a 3D scan of the eye, allowing optometrists to see a clear representation of your eye’s health. It’s a scan of the eye, nothing more — but it is incredibly accurate in its detail. If anything, misdiagnosis risk decreases with its usage as it enables to see minute details and to distinguish features that are not visible with traditional fundus photography.1

For more information about OCT and how it can be used to detect certain eye conditions, as well as manage them, you can find similar content here. To book an OCT scan, just contact your local store


1. Morgan JI. The fundus photo has met its match: optical coherence tomography and adaptive optics ophthalmoscopy are here to stay. Ophthalmic Physiol Opt. 2016;36(3):218–239. [Online]. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4963017/ [Accessed 13 November 2019].

2. Retina Specialists. (no date). Investigations: Optical Coherence Tomography (OCT) Scanning. Online]. Available at: http://retinaspecialists.co.nz/investigations/optical-coherence-tomography-oct-scanning/ [Accessed 13 November 2019].

3. Ophthalmology Web. (no date). SPECTRALIS Diagnostic Imaging Platform from Heidelberg Engineering, Inc. Available at: https://www.ophthalmologyweb.com/6001-Spectral-Domain-OCT-Optical-Coherence-Tomography-SD-OCT/55059-Spectralis-Diagnostic-Imaging-Platform/?pda=5458|55059_2_0||| [Accessed 13 November 2019].

4. Ophthalmology Web. (no date). Retina Scan Duo Optical Coherence Tomography from NIDEK. Available at: https://www.ophthalmologyweb.com/5458-Optical-Coherence-Tomography-OCT-Imaging-Systems/6430015-Optical-Coherence-Tomography-Retina-Scan-Duo/?pda=5458|6430015_4_0||| [Accessed 13 November 2019].