Ophthalmoscopy is an exam your doctor, optometrist, or ophthalmologist uses to look into the back of your eye. With it, he can see the retina (which senses light and images), the optic disk (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?
It can be done during an appointment with your doctor. He’ll use a handheld device called an ophthalmoscope to look into your eyes. There are two kinds of ophthalmoscopes. The one that looks a bit like a telescope is called a panoptic. The traditional type of ophthalmoscope is more compact and is called a standard head. The test is a routine part of an eye exam.
How Is an Ophthalmoscopy Done?
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 he'll use the ophthalmoscope to shine a light straight into your eyes. It has two or three tiny lenses that allow him 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. He’ll hold your eye open while shining the light into your eyes. This method lets your doctor to get a much better look at the entire retina, including the front portions which are hard to see with the 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 ophthalmoscopy: In 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. Your doctor will have you rest your chin and forehead on something to keep your head steady. Then he'll use the microscope and a tiny lens to look into your eye. What the doctor sees is similar to indirect ophthalmoscopy, but the images are much bigger.
You may have to get your eyes dilated before any of these exams. It's a requirement for indirect ophthalmoscopy and optional for the other two. Still, your doctor may want to do it to get a better view.
Your doctor will put drops in your eyes and wait for 20 minutes for them take effect. Then he’ll do the exam. The drops will keep your eye 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 to 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 okay. But, if the doctor sees spots on your retina or it’s swollen, these could be signs of disease.
The diseases your doctor might find during the exam include:
- High blood pressure
- Loss of sharp vision due to aging (macular degeneration)
- Separation of the retina from the back of the eye (retinal tear)
An ophthalmoscopy is the best way to diagnose these diseases. Your treatment will depend on what your doctor finds.