When patients come to our office for eye exams, many times there is testing that we do to help us diagnosing problems. One of these tests uses Optical Coherence Tomography, or OCT. Pictures taken with our OCT machine are generated by light waves that reflect off the back of the eye or retina, creating images similar to what could be produced by a low power microscope. The OCT also provides cross-sectional images. These images can display the various layers of the retina. This technology is also used to image the optic nerve, which is important in glaucoma treatment and management.
OCT is a non-invasive and no-contact test that doesn't require preparation from the patient. There is no exposure to radiation since the machine uses light to obtain the images. The patient sits in front of a machine, a couple of bright flashes like a normal camera flash go off, and then the photos can be viewed on the machine within a minute.
The OCT is an extremely valuable tool used to help diagnose and manage common retinal eye diseases such as macular degeneration, macular edema (fluid in the retina), and macular hole/epiretinal membranes. We use the initial OCT images to aid in making a definitive diagnosis. The OCT compares these initial images of your eye to a database of images of normal eyes matched to your age. In this way, the first OCT images we take can help point out potential issues if there is something that looks different from normal or average. Subsequent OCT images can then compare how you look now compared to how you looked initially. This can be very valuable in gauging how well treatment is working or if the problem is progressing.
The other common use of the OCT is for monitoring and managing glaucoma. We usually take initial images of the optic nerve, and the OCT can then compare these images to those of age-matched healthy control patients. The OCT will usually be repeated every year so we can follow any changes or progression over time.
The advent of OCT has revolutionized the way we evaluate the retina because we can now detect subtle findings not otherwise easily seen during clinical exams. This makes the OCT one of the most valuable tests we can do in our office.