Ophthalmoscopy

Test Overview

Ophthalmoscopy is a test that allows a health professional to see inside the back of the eye (called the fundus) and other structures using a magnifying instrument (ophthalmoscope) and a light source. It is done as part of an eye examination and may be done as part of a routine physical examination.

The fundus contains a lining of nerve cells (the retina), which detects images seen by the clear, outer covering of the eye (cornea). The fundus also contains blood vessels and the optic nerve. See a picture of the structures of the eye .

There are two types of ophthalmoscopy.

• Direct ophthalmoscopy. Your health professional uses an instrument about the size of a small flashlight with several lenses that can magnify up to about 15 times. This type of ophthalmoscopy is most commonly done during a routine physical examination.
• Indirect ophthalmoscopy. Your health professional wears a light attached to a headband and uses a small handheld lens. Indirect ophthalmoscopy provides a wider view of the inside of the eye and allows a better view of the fundus even if the lens is clouded by cataracts.

Why It Is Done

Ophthalmoscopy is done to:

• Detect problems or diseases of the eye, such as retina problems.
• Help diagnose other conditions or diseases that damage the eye.
• Evaluate symptoms, such as headaches.
• Detect other problems or diseases, such as head injuries or brain tumors.

How To Prepare

No special preparation is needed before having this test.

Your health professional 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 dilate the pupil fully. Your health professional may also use eyedrops to numb the surface of your eyes. Tell your health professional if:

• You or anyone else in your family has glaucoma.
• You are allergic to dilating or anesthetic eyedrops.

You may have trouble focusing your eyes for several hours after the test. You may wish to arrange 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 health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may indicate. 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

Direct ophthalmoscopy

This is the most common type of examination to look at structures inside the eye.

• Your eyes may be dilated, and you will be seated in a darkened room and asked to stare straight ahead at some distant spot in the room.
• Looking through the ophthalmoscope, your health professional will move very close to your face and shine a bright light into one of your eyes. Each eye is examined separately.
• Try to hold your eyes steady without blinking.

This examination takes 3 to 5 minutes. See a picture of a direct ophthalmoscopic examination .

Indirect ophthalmoscopy

This type of ophthalmoscopic examination gives a more complete view of the retina than direct ophthalmoscopy. It is usually done by an ophthalmologist.

• Your eyes will be dilated, and you will be asked to sit in a reclining or semi-reclining position in a darkened room.
• Your health professional will hold your eye open, shine a very bright light into it, and examine it through a special lens.
• Your health professional may ask you to look in different directions and may apply pressure to your eyeball through the skin of your eyelids with a small, blunt instrument to help bring the edges of your fundus into view.

This examination takes between 5 and 10 minutes. See a picture of an indirect ophthalmoscopic examination .

How It Feels

Direct ophthalmoscopy

During direct ophthalmoscopy, you may hear a clicking sound as the instrument is adjusted to focus on different structures in the eye. The light is sometimes very intense, and you may see spots for a short time following the examination. Some people report seeing light spots or branching images. These are actually the outlines of the blood vessels of the retina.

Indirect ophthalmoscopy

With indirect ophthalmoscopy, the light is much more intense and may be somewhat uncomfortable. Pressure applied to your eyeball with the blunt instrument also may be uncomfortable. After-images are common with this test. If the test is painful, let the health professional know.

When dilating eyedrops are used

Dilating drops may make your eyes sting and cause a medicine taste in your mouth. You will have difficulty focusing your eyes for up to 6 hours after your eyes have been dilated. Your distance vision usually is not affected as much as your near vision, though your eyes may be very sensitive to light. Do not drive for several hours after your eyes have been dilated. Wearing sunglasses may make you more comfortable until the effect of the drops wears off.

Risks

In some people, the dilating or anesthetic eyedrops can cause:

• Brief episodes of nausea, vomiting, dry mouth, flushing, and dizziness.
• An allergic reaction.
• A sudden increase in pressure inside the eyeball (closed-angle glaucoma).

Call your health professional immediately if you have severe and sudden eye pain, vision problems (halos may appear around light), or loss of vision after the examination.

Results

Ophthalmoscopy is a test that allows a health professional to see inside the back of the eye (called the fundus) and other structures using a magnifying instrument (ophthalmoscope) and a light source.

What Affects the Test

Factors that can interfere with your test or the accuracy of the results include:

• The inability to remain still during the exam.
• Eye problems, such as incomplete pupil dilation, cataracts, or cloudiness of the liquid inside the eyeball.

What To Think About

• Other eye tests may be done routinely along with ophthalmoscopy, including vision testing and tonometry testing for glaucoma. For more information, see the medical tests Vision Tests and Tonometry.
• Direct ophthalmoscopy is done more frequently than indirect ophthalmoscopy. Indirect ophthalmoscopy is a more difficult procedure and requires greater skill and more specialized equipment than direct ophthalmology, so it is generally done by ophthalmologists and optometrists.
• Indirect ophthalmoscopy has several advantages over direct ophthalmoscopy:
  • It allows better visualization of the inside of the eye when a cataract is present.
  • It provides a three-dimensional (3-D) view of the back of the eye, allowing a more detailed view of certain eye conditions (such as growths, optic nerve swelling, or retinal detachment).
  • It allows a wider view of the back of the eye than direct ophthalmoscopy.
• If your health professional suspects a problem with the blood vessels in your eye, a test called eye angiography may be done. This test uses fluorescein dye and a camera to photograph blood vessels in the eye. For more information, see the medical test Eye Angiogram.

References

Other Works Consulted

• Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.

• Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.

• Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.

• Pagana KD, Pagana TJ (2002). Mosby's Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.

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