Slit-lamp exam

Definition

The slit-lamp examination looks at structures that are at the front of the eye.

Alternative Names

Why the Test is Performed

The test is used to examine the eyelids, the sclera, conjunctiva, iris, lens, and the cornea.

How the Test is Performed

The slit-lamp is a low-power microscope combined with a high-intensity light source that can be focused to shine in a thin beam.

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 examine your eyes and may touch a fine strip of paper stained with an orange-colored dye (fluorescein) to the side of your eye. The dye stains the tear film on the surface of the eye to help with the examination. The dye rinses out of the eye with tears.

After this examination, drops may be placed in your eyes to dilate the pupils. The drops take about 15 to 20 minutes to work. The examination is then repeated, allowing the back of the eye to be examined.

How to Prepare for the Test

No special preparation is necessary for this test.

How the Test Will Feel

Your eyes will be sensitive to light for a few hours after the exam if dilating drops are used.

Risks

The dilating drops may cause increased pressure in the eye with nausea and pain. This is very rare, but you should IMMEDIATELY return to your doctor's office if you experience either of these symptoms.

Normal Results

Structures in the eye are found to be normal.

What Abnormal Results Mean

The slit lamp exam may detect many diseases of the eye, including:

• Cataract
• Corneal injury
• Dry eye syndrome
• Macular degeneration
• Retinal detachment
• Retinal vessel occlusion
• Retinitis pigmentosa
• Uveitis