Slit Lamp Examination

How It Is Done

Most of the time, a slit lamp examination is done by an ophthalmologist or optometrist. In some situations, a family medicine doctor or an emergency medicine specialist may perform the test.

• Your eyes may be dilated. Anesthetic eyedrops may be used to numb your eye if a foreign body is to be removed or if eye pressure is being measured (tonometry).
• You will sit in a chair and rest your chin and forehead against bars on the slit lamp. The lights in the room will be dimmed.
• The slit lamp will be placed in front of your eyes, in line with the health professional's eyes. Focus your eyes in the direction requested by the health professional and try to hold your eyes steady without blinking.
• A narrow beam of bright light from the slit lamp is directed into your eye while the health professional looks through the microscope. In some cases, a camera may be attached to the slit lamp to take photographs of different parts of the eye. See a picture of a slit lamp examination.

If a foreign body is present or if the cornea appears infected or injured, a test called fluorescein staining may be done along with a slit lamp examination.

• During this test, your health professional applies a yellow dye called fluorescein as an eyedrop or as a paper strip that is gently touched to the inside of your lower eyelid. The dye dissolves in your tears, coats your cornea, and collects temporarily in any scratches or other abnormal areas. The rest of the dye is washed away by your tears.
• Your health professional shines a blue light onto your eye. The fluorescein glows bright green under the light, allowing the health professional to see scratches, ulcers, burns, or areas of irritation from an infection or dryness.

A slit lamp examination takes about 5 to 10 minutes.

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Author:	Maria G. Essig, MS, ELS	Last Updated: July 6, 2007
Medical Review:	Kathleen Romito, MD - Family Medicine Carol L. Karp, MD - Ophthalmology
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