How the test is performed
There are different types of ophthalmoscopy.
- Direct ophthalmoscopy: You will be seated in a darkened room. The health care provider performs this common exam by shining a beam of light through the pupil using an instrument called an ophthalmoscope. An ophthalmoscope is about the size of a flashlight. It has a light and several different tiny lenses that allow the examiner to view the back of the eyeball.
- Indirect ophthalmoscopy: You will either lie or sit in a semi-reclined position. The health care provider holds your eye open while shining a very bright light into the eye using an instrument worn on the head. (The instrument looks like a miner's light.) The health care provider views the back of the eye through a hand-held lens held close to your eye. Some pressure may be applied to the eyeball using a small, blunt probe. You will be asked to look in various directions.
- Slit-lamp ophthalmoscopy: You will sit in a chair with the instrument placed in front of you. You will be asked to rest your chin and forehead on a support to keep your head steady. The health care provider will use the microscope part of the slit lamp and a tiny lens placed close to the front of the eye. The health care provider can see about the same with this technique as with indirect ophthalmoscopy, but with higher magnification.
The opthalmoscopy examination usually takes about 5 to 10 minutes.
How to prepare for the test
Indirect ophthalmoscopy and slit-lamp ophthalmoscopy are performed after eyedrops are placed to widen (dilate) the pupils. Direct ophthalmoscopy and slit-lamp ophthalmoscopy can be performed with or without the pupil dilated.
The eyedrops may make it hard for you to focus your eyes for several hours. You should arrange to have someone drive you after the examination. Wearing sunglasses or tinted lenses will help make your dilated pupils more comfortable.
You should tell the health care provider if you:
- Are allergic to any medicines
- Are taking any medicines
- Have glaucoma or a family history of glaucoma
How the test will feel
The bright light will be uncomfortable, but the test is not painful.
You may briefly see images after the light shines in your eyes. The light is brighter with indirect ophthalmoscopy, so the sensation of seeing after-images may be greater.
Pressure on the eye during indirect ophthalmoscopy by may be slightly uncomfortable, but it should not be painful.
If eyedrops are used, they may sting briefly when placed in the eyes. You may also have an unusual taste in your mouth.
Why the test is performed
Ophthalmoscopy is done as part of a routine physical or complete eye examination.
It is used to detect and evaluate symptoms of retinal detachment or eye diseases such as glaucoma.
Ophthalmoscopy may also be done if you have signs or symptoms of high blood pressure, diabetes, or other diseases that affect the blood vessels.
The retina, blood vessels, and the optic disc should appear normal.
What abnormal results mean
Abnormal results may be seen on ophthalmoscopy with any of the following conditions:
- CMV retinitis
- High blood pressure
- Macular degeneration
- Melanoma of the eye
- Optic nerve problems
- Retinal tear or detachment
What the risks are
The test itself involves no risk. The dilating eye drops may rarely cause:
- An attack of narrow-angle glaucoma
- Dryness of the mouth
If glaucoma is suspected, drops usually are not used.
Ophthalmoscopy is considered to be 90-95% accurate. It can detect the early stages and effects of many serious diseases.
American Academy of Ophthalmology Preferred Practice Patterns Committee. Preferred Practice Pattern Guidelines. Comprehensive Adult Medical Eye Evaluation. Available at http://one.aao.org/CE/PracticeGuidelines/PPP_Content.aspx?cid=64e9df91-d.... Accessed February 26, 2013.
Colenbrander A. Principles of ophthalmoscopy. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:vol 1, chap 63.
Miller D, Thall EH, Atebara NH. Ophthalmic instrumentation. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. Philadelphia, PA: Elsevier Mosby; 2008:chap 2.10.
Volk D. Aspheric lenses. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:vol 1, chap 50.