OCT Scans are Used to More Accurately Diagnose & Treat Many Eye Diseases

Optical Coherence Tomography provides better resolution than an MRI and Helps Diagnose Retina & Corneal Disease and Glaucoma

Optical Coherence Tomography (“ OCT”) is a painless, non-contact, non-invasive imaging technique that we use to obtain high resolution cross-sectional and three dimensional images of the retina, cornea and anterior chamber of the eye. OCT provides images at much higher clarity and resolution than any other imaging instruments such as MRI or ultrasound. Optical Coherence Tomography obtains sub-surface images of translucent or opaque materials at a resolution equivalent to a low-power microscope.

How OCT Works

OCT produces cross-sectional images and three-dimensional imaging of the cornea and the anterior segment of the eye and the retina using the optical backscattering of light similar to B-scan ultrasonography. It images reflections from within tissue to provide cross-sectional views. The physics principle allowing the filtering of scattered light is optical coherence. OCT delivers high resolution because it is based on light, rather than sound or radio frequency. An optical beam of infrared light is directed at the tissue and a small portion of this light that reflects from sub-surface features is collected. Most of the light is scattered instead of reflected.

 

OCT and ultrasound use echo location principles which rely on sound or light to navigate and locate. Other medical imaging techniques such as computerized axial tomography (CAT scan), magnetic resonance imaging (MRI), or positron emission tomography (PET scan) do not utilize the echolocation principle.

The OCT technique is limited to imaging 1 to 2 mm below the surface in biological tissue because at greater depths the proportion of light that escapes without scattering is too small to be detected or measured. No preparation of the human tissue is required and OCT scans are safe using near infrared light. Using long wavelength light allows it to enter the biological tissue, which is the scattering medium of the light.

 

Why is it used?

 

There are TWO possible reasons for your doctor to order this procedure:

a. Early detection of glaucoma OR

b. Monitoring the effectiveness of current therapies in arresting the effects of the disease of glaucoma on your vision.

 

Does it replace a visual field?

 

No, it does not. A visual field evaluates your level of visual function. However, the structural damage from glaucoma occurs up to FIVE years PRIOR to the patient experiencing VISION loss. With HRT a personalized visual map of your retina and optic nerve is compared (by computer technology) to the new scan, and any changes are highlighted. Your doctor can immediately see if your glaucoma is progressing and then prescribe needed therapies, BEFORE vision loss is experienced.

 

If you would like further information about Optical Coherence Tomography or would like to set up an appointment to be evaluated by Dr. Walt Bogart of the Carolina Eye Center, call our office at: 803-794-0000.