What Is an OCT Scan?

What does OCT stand for? 

OCT stands for Optical Coherence Tomography. It is a non-invasive imaging scan that produces a detailed 3D image of the innermost layers of your eye, similar to what an ultrasound does for internal organs, but using light instead of sound. 

OCT scans are considered the Gold Standard for detecting and managing serious eye diseases, including macular degeneration and glaucoma. 

What does an OCT scan show? 

An OCT scan images the layers beneath the surface of your retina in extraordinary detail. This allows your optometrist to identify structural changes that are completely invisible to the naked eye or even a standard slit lamp examination. 

Conditions an OCT scan can help detect or monitor include: 

• Glaucoma:a blinding eye disease that develops slowly, often with no symptoms until significant damage has already occurred 
• Macular degeneration: changes to the central part of the retina that affects detailed vision
• Diabetic retinopathy:retinal changes associated with diabetes, which can appear before other symptoms 
• Other retinal disorders including swelling, fluid accumulation and structural changes

Is an OCT scan painful or invasive? 

Not at all. OCT imaging is safe, non-invasive, and comfortable. You simply look into the device while it scans your eye with a beam of light. There is no physical contact with the eye and no eye drops are required in most cases. The process takes only seconds. 

Remarkable progress has been made in recent years to both the quality and speed of OCT imaging, making it faster and more accurate than ever before. 

Why would my optometrist recommend an OCT scan? 

Your optometrist may recommend an OCT scan if you have a personal or family history of glaucoma, macular degeneration or diabetes, or as part of a comprehensive eye exam to establish a baseline record of your eye health. 

The most compelling reason is early detection. An estimated 300,000 Australians have glaucoma, but around 50% do not know it yet.† Glaucoma develops slowly and produces no noticeable symptoms until vision loss is already underway. Regular OCT scans are the most effective way to detect it before that happens. 

Similarly, around 38% of type 2 diabetic patients show some level of diabetic retinopathy at the time of their diabetes diagnosis and retinal changes can precede a formal diabetes diagnosis by as many as 7 years.‡ 

How is an OCT scan different from a standard eye test? 

A standard eye test checks your vision prescription and looks for surface-level signs of eye disease. An OCT scan goes much deeper, imaging the structure of the back of your eye in 3D cross-section to reveal changes that a standard test simply cannot detect. 

Does Medicare cover OCT scans? 

Medicare covers part of your comprehensive optometry consultation. There may be a small out-of-pocket gap for certain Advanced Eyecare Technology, depending on your individual clinical needs. At George & Matilda, putting patients first means being open and transparent about any costs before proceeding. Your optometrist will only recommend what is most beneficial for your long-term vision and wellbeing. 

† Glaucoma Australia (glaucoma.org.au)

‡ Statistics of Optical Coherence Tomography Data From Human Retina, Grzywacz et al. (2010)