Optical coherence tomography, also called OCT, is a method for imaging the various layers of the retina, the optic nerve head, and the anterior segment of the eye. Similar to ultrasound, individual layers of tissue are scanned without touching the eye and displayed as a cross-section.

A completely safe light source is used. A typical example of an OCT image of the retina is shown. The examination lasts a few seconds, does not require the administration of drugs, and is totally painless.

OCT supports the eyecare professional in diagnosing a disease and monitoring change over time. The OCT is particularly useful for issues concerning fluid retention and swelling in the retina, which can occur, for example, with age-related macular degeneration (AMD) or diabetes. But very early signs of a pathological change can also be detected.

Examinations of the optic nerve head

An OCT examination of the optic nerve head generates a three-dimensional image of the optic nerve head (location where the optic nerve exits the eyeball and goes to the brain) and the surrounding retina. These images provide information about the structure and condition of the optic nerve head. Pathological changes can be detected early and documented reliably.

Regularly performed OCT examinations are useful for analysing the progression of advancing damage to the optic nerve head and the surrounding retina. Glaucoma treatment can be adapted to the progression of the disease. Today, an OCT examination is regarded worldwide as the standard for diagnosing glaucoma, since glaucoma becomes noticeable very early through a change in the optic nerve head.The examination does not require the administration of drugs and is painless.

What is the process?

During an OCT examination, a safe laser beam scans the desired area of the retina at three different levels in seconds. A computer develops a physical profile of the tissue surface from the generated image. The generated images are three-dimensional and very high in contrast.

The surface structure of the optic nerve head and the blood vessels are reproduced exactly. The computer automatically compares the gathered structure data of the optic nerve head with a normal database, depending on factors such as age, gender, and ethnicity. This database contains both healthy and diseased eyes.

This process allows the risk of suffering from glaucoma damage to be determined individually for the examined eye. Any pathological changes can be documented early.

Optical coherence tomography (OCT) of the optic nerve head

A circular “cut” around the optic nerve head is used to measure the thickness of the nerve fibre layer in this area.

The thickness of the nerve fibre layer can provide information about the number of existing nerve fibres and any loss. The loss of nerve fibres can result in visual impairments.