Retinal Imaging: Purpose & Procedure Details

How is retinal imaging performed?

There are three main methods that eye care specialists use to take digital pictures of your eye’s fundus (the inner, back surface of your eye). These include:

• Color fundus photos. Fundus is another term for the back of the eye. Providers have used fundus cameras for decades to take pictures inside your eye. You’ll see bright flashes of light while the camera takes pictures. Advances in technology allow precise digital retinal images in high resolution. Some cameras can also take wide-field views of your fundus, allowing your eye care team to see a larger area of your retina. One strength of this imaging method is its ability to show your blood vessels and reveal signs of diabetes-related retinopathy.
• Optical coherence tomography (OCT). This is a common imaging test your provider may perform to see cross-sectional views of the layers of your retina in the macula region and optic nerve. This method can show each layer of your retina and measure how thick it is. It can help diagnose conditions like diabetes-related macular edema and macular degeneration.

In all these cases, you sit comfortably in a chair and move your face close to the camera device. Your provider shows you where to place your forehead and chin. Nothing touches your eye during retinal imaging.

Providers sometimes use one or more of the above methods at the same time. They may also use one of the methods along with fluorescein angiography. This technique is minimally invasive. Nothing touches your eyes, but your provider injects a dye into a vein in your arm. This dye travels through your blood vessels, including those in your eyes. It reveals blockages or other problems in those vessels.

What happens before the test?

Your provider will tell you about the procedure and why you’re having it. They may ask you to give consent.

Providers usually put drops into your eyes to dilate your pupils. That’s because your pupil is the window that the camera sees through to capture pictures of your fundus. A wider pupil typically leads to better images. Make sure you arrange for someone to drive you home. Your vision will be blurry, and you’ll be sensitive to light for a few hours after pupil dilation.

What happens during the test?

Retinal imaging, including fundus photography and OCT, is fast and painless. Here’s what you can expect:

1. You’ll sit in a chair in front of the imaging device. Your provider will make sure you’re comfortable.
2. You’ll position your face so your chin rests comfortably in a chin rest, and your forehead presses gently against a bar.
3. Your provider will align the camera and begin taking photos. They’ll capture images of one eye at a time.
4. You may need to focus on a green light. The light may be bright and cause brief discomfort as you look at it.
5. Your provider will tell you when you can sit back from the camera.

Retinal imaging typically takes five to 10 minutes. If your provider uses fluorescein angiography, the process may take up to 30 minutes.

What can I expect after the test?

If your provider dilates your eyes, you’ll have blurry vision and sensitivity to light for a few hours. So, give your eyes a rest. Don’t drive, read or look at screens. Wear sunglasses to protect your eyes when you’re outside.

What are the risks of retinal imaging?

Retinal imaging, including fundus photography and OCT, is safe with no known risks. Your provider simply uses a camera to create digital images of your eyes.

Fluorescein angiography is low risk but may cause side effects like temporary skin discoloration (a slight yellow tint) or urine that appears dark yellow to orange. These effects go away within 24 hours.

Rarely, fluorescein may cause an allergic reaction (hives or itching). The risk of anaphylaxis is extremely small. People who are sensitive to fluorescein may experience:

• Dizziness.
• Dry mouth.
• Increased heart rate.
• Metallic taste in their mouth (brief).
• Nausea or vomiting.
• Sneezing.