Optical coherence tomography eye
Informed by recognized medical guidance
Overview
Optical coherence tomography (OCT) is a quick, painless eye scan that uses light waves to take detailed cross-section pictures of your retina — the light-sensitive layer at the back of your eye. It helps your eye doctor see the layers of your retina clearly, almost like a 'CAT scan' for your eye.
Key facts
- The scan is non-invasive and takes only a few minutes.
- It does not use X-rays or radiation.
- OCT can help detect eye conditions early, such as age-related macular degeneration, glaucoma, and diabetic retinopathy.
- You may need eyedrops to dilate (widen) your pupils before the scan.
Yes, OCT is a very common test used in eye clinics and hospitals worldwide. Many people have it as part of a routine eye exam or to monitor an eye condition.
Anyone can have an OCT scan. It is often recommended for people with eye symptoms, those at risk of certain eye diseases, and older adults who are more likely to develop age-related eye problems.
Symptoms
- Sudden loss of vision in one or both eyes
- A curtain-like shadow over part of your vision
- Severe eye pain with nausea or vomiting
- Eye injury or chemical splash
- ⚠New floaters or flashes of light that do not go away
- ⚠Distortion of vision that comes on quickly
- ⚠Redness, swelling, or discharge from the eye
Common symptoms
- Blurry or hazy vision
- Distorted vision (straight lines appear wavy)
- Dark or empty spots in your vision
- Loss of central vision (trouble reading or recognising faces)
- Sudden flashes of light or new floaters (specks that drift across your vision)
Symptoms in children
- Poor vision that does not improve with glasses
- An eye that turns inward or outward
- Nystagmus (wobbly eyes)
- White reflection in the pupil in photos
Symptoms in older adults
- Gradual loss of sharp, clear vision
- Difficulty seeing in dim light
- Colours appearing less bright
- Need for brighter light when reading
- Difficulty with night driving
Causes
Main causes
- Optical coherence tomography is a diagnostic test, not a medical condition. It is used to detect eye conditions such as age-related macular degeneration, glaucoma, diabetic retinopathy, and retinal detachment.
Risk factors
- Age over 50
- Diabetes or high blood pressure
- Family history of eye disease
- Being short-sighted (myopia)
- Previous eye injury or surgery
- Smoking
When to see a doctor
See a doctor urgently if:
- Sudden vision loss or change in vision
- Bright flashes of light or a shower of new floaters
- Eye pain, redness, or sensitivity to light
Book a routine appointment if:
- Annual eye exams if you are over 60 or have diabetes
- Every two years for adults without symptoms or risk factors
- Any time you notice changes in your vision
Diagnosis
Your eye doctor will perform a comprehensive eye exam. If they suspect a retinal or optic nerve problem, they will likely recommend an OCT scan. The scan is done in the clinic using a machine that looks like a large camera.
Tests that may be done
- Optical coherence tomography (OCT) – the main scan
- Dilated eye exam – drops widen your pupils so the doctor can see the back of your eye
- Visual field test – to check your side (peripheral) vision
- Fluorescein angiography – a dye test that highlights blood vessels in the retina (not always needed)
What to expect at your appointment
You will sit in front of the OCT machine and rest your chin and forehead on supports. The technician will ask you to look at a target light while the machine scans your eye. You may see a bright light, but it should not hurt. The whole process takes about 5–10 minutes. Afterward, if you had dilating drops, your vision may be blurry for a few hours.
Treatment
An OCT scan itself does not require treatment. It helps your doctor diagnose eye conditions. The treatment will depend on what the scan shows. Your doctor will discuss the results with you and recommend the best next steps.
Self-care at home
- Follow your doctor's advice on managing any eye condition found.
- Wear sunglasses outdoors to protect your eyes from UV light.
- Keep up with regular eye exams as recommended.
- Manage overall health conditions like diabetes and high blood pressure.
Medical treatments
If an eye condition is found, treatment may include prescription eye drops, laser therapy, injections into the eye, or oral medications. Your doctor will explain which approach is best for your specific situation. Always follow your doctor's instructions carefully.
When is surgery considered?
For some conditions, such as a detached retina or advanced glaucoma, surgery may be needed. Your eye doctor will refer you to a specialist if surgery is an option.
Living with this condition
If you have an eye condition detected by OCT, you may need to adapt your daily activities. Use good lighting, magnifiers for reading, and arrange your home to avoid tripping hazards. Most people continue with their normal routines with minor adjustments.
Lifestyle tips
- Quit smoking – it harms your eyes and overall health.
- Protect your eyes from bright sunlight with UV-blocking sunglasses.
- If you have diabetes, keep your blood sugar under control.
- Wear protective eyewear during sports or DIY projects.
Diet and exercise
A diet rich in leafy green vegetables, colourful fruits, and fish high in omega-3 fatty acids may support eye health. Regular exercise helps control weight, blood pressure, and diabetes — all of which affect your eyes.
Mental health and emotional wellbeing
Finding out you have an eye condition can be worrying. It is normal to feel anxious or sad. Talk to your doctor about your concerns. Many eye conditions can be managed, and support is available. If you feel overwhelmed, consider speaking with a counsellor.
Prevention
You cannot always prevent eye diseases, but early detection through regular eye exams — including OCT scans when recommended — gives you the best chance to preserve your vision. Managing overall health and protecting your eyes also help.
Screening programmes
Routine eye exams are the best screening tool. Your doctor will let you know how often you need an OCT scan based on your age, risk factors, and any eye symptoms.
Complications
If left untreated
- Without diagnosis and treatment, eye conditions such as glaucoma, macular degeneration, or diabetic retinopathy can lead to permanent vision loss.
- Delaying treatment may make it harder to restore or preserve vision.
Long-term outlook
The outlook is generally good when eye conditions are caught early. Many people maintain useful vision for many years. OCT scans help doctors spot problems at an early stage, which often means simpler and more effective treatment.
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Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Related conditions
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 16, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.
Guidance may differ by country or region. Confirm local recommendations with a qualified healthcare provider.