Optical coherence tomography (OCT) is a non-invasive imaging test. OCT uses light waves to take cross-sectional pictures of your retina. With OCT, your ophthalmologist can see each of the different layers of the retina. This allows your ophthalmologist to map and measure their thickness. These measurements aid diagnosis. They also provide treatment guidance for glaucoma and retinal diseases. These retinal diseases include age-related macular degeneration (AMD) and diabetic eye disease.

To prepare you for an OCT exam, your ophthalmologist may or may not put dilated eye drops in your eyes. These drops dilate your pupil and make it easier to examine the retina. You will sit in front of the OCT machine and put your head on a support to keep it still. The equipment will then scan your eye without touching it. The scan takes about 5 to 10 minutes.If your eyes are dilated, they may be sensitive to light for a few hours after the exam.