The slit-lamp examination looks at structures that are at the front of the eye.
The slit-lamp is a low-power microscope combined with a high-intensity light source that can be focused as 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, especially the eyelids, cornea, conjunctiva, sclera, and iris. Often a yellow dye (fluorescein) is used to help examine the cornea and tear layer. The dye is either added as an eyedrop. Or, the provider may touch a fine strip of paper stained with the dye to the white of your eye. The dye rinses out of the eye with tears as you blink.
Next, drops may be placed in your eyes to widen (dilate) your pupils. The drops take about 15 to 20 minutes to work. The slit-lamp examination is then repeated using another small lens held close to the eye, so the back of the eye can be examined.
No special preparation is needed for this test.
Your eyes will be sensitive to light for a few hours after the exam if dilating drops are used.
This test is used to examine the:
Structures in the eye are found to be normal.
The slit lamp exam may detect many diseases of the eye, including:
This list does not include all possible diseases of the eye.
If you receive drops to dilate your eyes for the ophthalmoscopy, your vision will be blurred.
In rare cases, the dilating eyedrops cause:
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Chuck RS, Dunn SP, Flaxel CJ; American Academy of Ophthalmology Preferred Practice Pattern Committee, et al. Comprehensive adult medical eye evaluation preferred practice pattern. Ophthalmology. 2021;128(1):1-29. doi.org/10.1016/j.ophtha.2020.10.024. Published November 12, 2020.
Prokopich CL, Hrynchak P, Flanagan JG, Hynes AF, Chisholm C. Ocular health assessment. In: Elliott DB, ed. Clinical Procedures in Primary Eye Care. 5th ed. Philadelphia, PA: Elsevier; 2021:chap 7.
Reviewed By: Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.