What Is Optical Coherence Tomography?
Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) are non-invasive imaging tests. They use light waves to take cross-section pictures of your retina.
With OCT, your ophthalmologist can see each of the retina’s distinctive layers. This allows your ophthalmologist to map and measure their thickness. These measurements help with diagnosis. They also guide treatment for glaucoma as well as retinal disease, like age-related macular degeneration (AMD) and diabetic eye disease.
Optical coherence tomography angiography (OCTA) takes pictures of the blood vessels in and under the retina. OCTA is like fluorescein angiography. But it is a much quicker test and does not use a dye.
Video: Optical Coherence Tomography
What happens during OCT?
To prepare you for an OCT exam, your ophthalmologist may or may not put dilating eye drops in your eyes. These drops widen your pupil and make it easier to examine the retina.
You will sit in front of the OCT machine and rest your head on a support to keep it motionless. The equipment will then scan your eye without touching it. Scanning takes about 5 to 10 minutes. If your eyes were dilated, they may be sensitive to light for several hours after the exam.
What Conditions Can OCT Help Diagnose?
OCT and OCTA help diagnose many eye conditions, including:
OCT is often used to evaluate disorders of the optic nerve as well. The OCT exam helps your ophthalmologist see changes to the fibers of the optic nerve. For example, it can detect changes caused by glaucoma.
OCT relies on light waves. It cannot be used with conditions that interfere with light passing through the eye. These conditions include dense cataracts or significant bleeding in the vitreous.