An optical coherence tomography (OCT) scan uses light beams to make detailed images of the inside of the eye. This test can find eye problems such as age-related macular degeneration or glaucoma.

During the test, light beams are focused onto the back of the eye. The test can help find retina or optic nerve problems. Before this test, the pupils may need to be widened using drops, or dilated. OCT takes about 10 to 20 minutes.