What is Optical Coherence Tomography?

Optical Coherence Tomography (OCT) is an imaging technique which makes it possible to obtain a 3D view of the tissues. OCT is just like ultrasound testing; the only difference being that, here imaging is done using light in place of sound. 

 

How is OCT done?

This is a painless test which is performed without touching your eyes. Usually your eyes are required to be dilated with the use of special drops. You will then be asked to sit in front of a special camera which will take pictures of the structures inside your eyes. If you are able to co-operate well, the test can be finished in a few minutes.

 

Why is OCT done?

Optical Coherence Tomography can be used to detect many eye conditions like:

Retina: The macula (an area near the centre of the retina) can be studied. This is especially useful in the following conditions:

• Choroidal Neovascularisation (A condition where new blood vessels grow abnormally and is seen in the disease called age related macular degeneration or ARMD)
• Macular hole (A hole in the centre of your retina, a region called the macula)
• Posterior Vitreous Detachment (A condition where the vitreous or jelly separates from your retina)

 

Glaucoma: In Glaucoma, an eye condition where there is vision loss usually due to raised eye pressure, OCT is done for two purposes:

• To study the angle of the front chamber of the eye. This is the angle between the iris and cornea and may be affected in glaucoma.
• To analyse the optic disc. This is the region where the nerve carrying information to the brain leaves the retina. This gets damaged in Glaucoma which slowly leads to irreversible blindness.

 

Corneal Thickness: OCT can also be used to measure the thickness of the cornea i.e the outer transparent layer of the eye. This is required to be done in diseases of the cornea like ulcers and swelling or before surgeries like Lasik.