This test is used to produce detailed images of the retina. It is much like ultrasound, except that it uses light beams instead of sound waves. Optical coherence tomography helps physicians evaluate problems with the retina such as swelling and holes, as well as abnormalities of the optic nerve. It can be useful in diagnosing and monitoring glaucoma.
During the exam, focused beams of light are directed into the eye. The light beams scan the structural features of the retina, producing a cross-section image similar to a topographical map. The test takes about 10 to 20 minutes and usually requires dilation of the pupils.