Ophthalmoscopy (also called fundoscopy) is a test that lets a doctor see inside the back of the eye, which is called the fundus. The doctor can also see other structures in the eye. He or she uses a magnifying tool called an ophthalmoscope and a light source to see inside the eye. The test is done as part of an eye exam. It may also be done as part of a routine physical exam.
The fundus has a lining of nerve cells called the retina. The retina detects images seen by the clear, outer covering of the eye, called the cornea. The fundus also contains blood vessels and the optic nerve.
There are two types of ophthalmoscopy.
- Direct ophthalmoscopy. Your doctor uses a tool that is about the size of a small flashlight. It has many lenses that can magnify up to about 15 times.
- Indirect ophthalmoscopy. Your doctor uses a small handheld lens and either a slit lamp microscope or a light attached to a headband. This test gives the doctor a wider view of the inside of the eye. It allows a better view of the fundus, even if the lens is clouded by cataracts.
Why It Is Done
Ophthalmoscopy is done to:
- Find problems or diseases of the eye, such as retina problems.
- Help find other conditions or diseases that damage the eye.
- Look for the cause of symptoms, such as headaches.
- Find other problems or diseases, such as head injuries or brain tumors.
How To Prepare
You do not need to do anything special to prepare for this test.
Your doctor may use eyedrops to widen (dilate) your pupils. This makes it easier to see the back of the eye. The eyedrops take about 15 to 20 minutes to fully dilate the pupil. Your doctor may also use eyedrops to numb the surface of your eyes. Tell your doctor if:
- You or anyone else in your family has glaucoma.
- You are allergic to eyedrops used to dilate or numb the eye.
You may have trouble focusing your eyes for several hours after the test. You may want to have someone drive you home after the test. You also will need to wear sunglasses when you go outside or into a brightly lit room.
Talk to your doctor if you have any concerns about the need for the test, its risks, how it will be done, or what the results mean. To help you understand the importance of this test, fill out the medical test information form( What is a PDF document? ).
How It Is Done
This type of exam can be done with or without eyedrops.
- Your eyes may be dilated. You will be seated in a darkened room and will be asked to stare straight ahead at some distant spot in the room.
- Looking through the ophthalmoscope, your doctor will move very close to your face and shine a bright light into one of your eyes. Each eye is checked separately.
- Try to hold your eyes steady without blinking.
This exam takes a few minutes.
This type of eye exam gives a more complete view of the retina than direct ophthalmoscopy. The exam is usually done by an ophthalmologist.
- Your eyes may be dilated. You may be asked to sit in a darkened room and to sit upright with your head on a chin rest.
- Your doctor will hold your eye open and shine a very bright light into it. He or she will look at the eye through a special lens.
- Your doctor may ask you to look in different directions. He or she may apply pressure to your eyeball through the skin of your eyelids by using a small, blunt tool. The pressure helps bring the edges of your fundus into view.
This exam takes a few minutes.
How It Feels
During direct ophthalmoscopy, you may hear a clicking sound as the tool is adjusted to focus on different structures in the eye. The light is sometimes very strong, so you may see spots for a short time after the exam. Some people report seeing light spots or branching images. These are really just the outlines of the blood vessels of the retina.
With indirect ophthalmoscopy, the light is much stronger. It may be slightly painful. Pressure applied to your eyeball with the blunt tool may also hurt a little. After-images are common with this test. If the test is painful, let the doctor know.
When dilating eyedrops are used
Dilating drops may make your eyes sting and cause a medicine taste in your mouth. You will have trouble focusing your eyes for up to 12 hours. Your distance vision usually is not affected as much as your near vision. Your eyes may be very sensitive to light. Do not drive for several hours after your eyes have been dilated, unless your doctor says it's okay. Wearing sunglasses may make you feel better until the drops wear off. To learn more, see the topic Dilated Eye Exam.
In some people, the dilating or numbing eyedrops can cause:
- Nausea, vomiting, dry mouth, flushing, and dizziness for a short time.
- An allergic reaction.
- A sudden increase in pressure inside the eyeball (closed-angle glaucoma).
Call your doctor right away if you have severe and sudden eye pain, vision problems such as halos that appear around lights, or loss of vision after the exam.
Ophthalmoscopy is a test that lets a doctor see inside the back of the eye, which is called the fundus. He or she can also see other structures in the eye. The doctor uses a magnifying tool called an ophthalmoscope and a light source to see inside the eye.
What Affects the Test
You may not be able to have the test, or the results may not be helpful, if:
- You can't stay still during the exam.
- You have certain eye problems such as cataracts, cloudiness of the liquid inside the eyeball, or pupils that don't dilate enough.
What To Think About
- Other eye tests may be done along with ophthalmoscopy. These may include vision testing and tonometry testing for glaucoma.
- Indirect ophthalmoscopy is harder to do and requires greater skill and more specialized tools than direct ophthalmoscopy. It is usually done by ophthalmologists and optometrists.
- Indirect ophthalmoscopy can be more helpful than direct ophthalmoscopy because:
- It lets the doctor see the inside of the eye better if you have a cataract.
- It provides a three-dimensional (3-D) view of the back of the eye. This gives the doctor a more detailed view of certain eye conditions, such as growths, optic nerve swelling, or a detached retina.
- It allows a wider view of the back of the eye.
- If your doctor thinks you may have a problem with the blood vessels in your eye, he or she may suggest a test called eye angiography. This test uses fluorescein dye and a camera to take pictures of blood vessels in the eye. To learn more, see the topic Eye Angiogram.
Other Works Consulted
- Chang DF (2011). Ophthalmologic examinations. In P Riordan-Eva, ET Cunningham, eds., Vaughan and Asbury's General Ophthalmology, 18th ed., pp. 27–57. New York: McGraw-Hill.