Ophthalmoscopy (also called fundoscopy or funduscopy) is an exam your doctor, optometrist, or ophthalmologist uses to look into the back of your eye. It lets them see the retina (which senses light and images), the optic disc (where the optic nerve takes the information to the brain), and blood vessels. It lets your doctor check for diseases and other eye problems.
When Would You Get the Test?
The test is a routine part of an eye exam. It can also be done during an appointment with your doctor.
They’ll use a device called an ophthalmoscope to look into your eyes. There are two types of ophthalmoscopes. One looks a bit like a telescope and is called a panoptic. The traditional type of ophthalmoscope is more compact and is called a standard head.
How Is an Ophthalmoscopy Done?
This depends on the type of ophthalmoscopy your doctor uses. There are three main types:
Direct ophthalmoscopy: Your exam takes place in a darkened room. If you wear glasses, you’ll have to take them off. Your doctor will ask you to stare directly ahead and keep your head still. Then they'll use the ophthalmoscope to shine light straight into your eyes. It has two or three tiny lenses that allow them to see inside.
Indirect ophthalmoscopy: This exam uses an indirect ophthalmoscope. It’s worn on the doctor's head and looks a lot like a miner's light. Your doctor will have you lie down or sit in a reclined position. They’ll hold your eye open while shining the light into your eyes. This method lets your doctor get a much better look at the entire retina, including the front portions that are hard to see with other methods. This can be combined with another exam technique called scleral depression. It brings the far edges of the retina into view so your doctor can see if there are any tears or if it’s detached.
Slit-lamp biomicroscopy: A similar type of exam is called slit-lamp biomicroscopy. For this exam, you'll sit in a chair in front of an instrument called a slit-lamp microscope. A slit lamp is a high-intensity light with several pieces of equipment combined into one device. It includes a binocular microscope on a base that moves in an arc, an adjustable light source, and a frame to rest your head on. The frame holds it steady during the exam. What the doctor sees is similar to indirect ophthalmoscopy, but the images are much bigger.
Your doctor has a lot of flexibility with the light. They can narrow and widen it, increase its brightness, and filter it with colors. By doing this, your doctor can focus on particular parts of your eyes and face.
When the slit lamp is coupled with a special magnifying lens, your doctor can see your retina and the optic nerve located in the back of your eye. Looking at them can help your doctor tell if you have glaucoma or if diabetes is affecting your eyes. The examination may also show tumors, blood clots, and hardening of the arteries caused by high blood pressure.
What Is the Doctor Looking At?
During your eye exam, your doctor will look at:
The skin around the eye. Your doctor can check the area for skin diseases and abrasions.
Your eyelids and eyelashes. They'll use the slit lamp to check for styes (oil gland infections), folliculitis (hair follicle infections), and tumors.
The surface of the eye. This includes the tissue under your eyelids and over the whites of your eyes. These areas can be swollen or infected. This can be caused by sexually transmitted diseases, allergies, or viruses.
The sclera. This is the protective outer layer of the eyeball. Next to the sclera is the episclera, which helps keep it healthy. These areas can get diseases related to allergies, autoimmune disorders (in which the body attacks itself), and gout (a type of arthritis).
The cornea. This is the layer of the eye that helps focus your vision. A slit-lamp exam may show your cornea isn’t as clear as it used to be. A number of things can cause your vision to blur.
The iris. The doctor will look at the colored disc that surrounds the pupil and any changes to allow more or less light into your eye. It can be affected by various diseases and conditions, including freckles or melanoma of the iris.
The lens. They can diagnose you with cataract (clouding of the lens). It’s located behind the pupil.
Though eye exams make some people squeamish, the procedures should be pain-free.
For any of these exams, you may have to get your pupils dilated to give your doctor a better view.
Your doctor will put drops in your eyes and wait for about 20 minutes for them to take effect. Then, they’ll do the exam. The drops will keep your pupils dilated for several hours. You’ll need to wear sunglasses once you get outside. Your vision may be blurry too, so you may need someone to drive you home. In rare cases, the eye drops make some people feel dizzy or can cause dry mouth or nausea.
How Long Is the Exam and Does It Hurt?
It takes 5-10 minutes, and there may be some minor discomfort. The eye drops can sting, and the bright light can be a little uncomfortable.
What Do the Results Mean?
If the retina, blood vessels, and optic disc look normal, everything is OK. But, if the doctor sees spots on your retina or it’s swollen, these could be signs of disease. An ophthalmoscopy is the best way to spot them.
The diseases your doctor might find during the exam include:
- High blood pressure
- Loss of sharp vision owing to aging (macular degeneration)
- Separation of the retina from the back of the eye (retinal tear)
Your treatment will depend on what your doctor finds.