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The slit lamp exam uses a tool that provides a magnified, three-dimensional (3-D) view of the parts of the eye. During the exam, your doctor can look at the front parts of the eye. These parts include the clear, outer covering (cornea), the lens, and the colored part (iris). The doctor can also see the front part of the thick fluid (vitreous gel) that fills the large space in the middle of the eye.
Special lenses can be placed between the slit lamp and the cornea (or on the cornea) to help the doctor see the deeper structures of the eye. These structures include the optic nerve, the retina, and the area where fluid drains out of the eye (drainage angle).
A camera may be attached to the slit lamp to take pictures of different parts of the eye.
Fluorescein dye may be used during a slit lamp exam. The dye makes it easier to see a foreign object, such as a metal fragment, or an infected or injured area on the cornea.
Routine slit lamp exams are done to find eye problems at an early stage and to guide treatment if eye problems develop.
A slit lamp exam may be done:
If you wear glasses or contact lenses, you will need to remove them before the slit lamp exam.
Eyedrops may be used to widen (dilate) your pupils and to numb the surface of your eyes. Before the test, tell your doctor if you have glaucoma or are allergic to eyedrops that dilate or numb your eyes.
If dilating drops are used, your eyes may be sensitive to light. You will have trouble focusing your eyes for several hours. If you know your eyes will be dilated, you may wish to find someone to 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 doctor if you have any concerns about the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form( What is a PDF document? ).
Most of the time, a slit lamp exam is done by an ophthalmologist or optometrist. In some cases, a family medicine doctor or an emergency medicine specialist may do the test.
A test called fluorescein staining may be done along with a slit lamp exam.
A slit lamp exam takes about 5 to 10 minutes.
It is usually not painful to have a slit lamp test.
The dilating drops may make your eyes sting and cause a medicine taste in your mouth. You will have trouble focusing your eyes for up to 12 hours. Your distance vision usually is not affected as much as your near vision. But your eyes may be very sensitive to light. Do not drive for several hours after your eyes have been dilated, unless your doctor says it's okay. Wearing sunglasses may make you more comfortable until the effect of the drops wears off.
Numbing drops usually wear off in about 30 minutes.
In some people, the dilating or numbing drops can cause:
Contact your doctor right away if you have severe and sudden eye pain, vision problems such as halos that appear around lights, or loss of vision after the exam.
The slit lamp exam uses a tool that provides a magnified, three-dimensional (3-D) view of the parts of the eye.
Not being able to stay still during a slit lamp exam may make it hard for your doctor to check your eyes.
Other Works Consulted
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
Current as of: May 5, 2019
Author: Healthwise StaffMedical Review: Kathleen Romito, MD - Family MedicineAdam Husney, MD - Family Medicine
Current as of:
May 5, 2019
Medical Review:Kathleen Romito, MD - Family Medicine & Adam Husney, MD - Family Medicine
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