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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
the retina, and the area where fluid drains out of the eye
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
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
optometrist. In some cases, a
family medicine doctor or an
emergency medicine specialist may do the
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
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
Not being able to stay still
during a slit lamp exam may make it hard for your doctor to check
Other Works Consulted
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
ByHealthwise StaffPrimary Medical ReviewerKathleen Romito, MD - Family MedicineSpecialist Medical ReviewerAdam Husney, MD - Family Medicine
Current as ofMay 17, 2017
Current as of:
May 17, 2017
Kathleen Romito, MD - Family Medicine
& Adam Husney, MD - Family Medicine
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