What is a slit lamp
Diseases of the eye can be difficult to diagnose during a general physical
examination. A doctor who specializes in treating eye problems, called an ophthalmologist,
is better able to examine and diagnose these conditions because the tools they
have are specific to the eyes. When you have an eye checkup, you will likely
undergo a slit lamp exam.
You will usually have the slit lamp exam at an optometry or ophthalmology
office. The exam is also called biomicroscopy. It allows the doctor to
microscopically examine your eyes for any abnormalities or problems.
happens during a slit lamp exam?
You do not have to prepare in advance for a slit lamp exam.
Once you are in the examination chair, the doctor will place an instrument
in front of you on which to rest your chin and forehead. This helps steady your
head for the exam. Your eye doctor may put drops in your eyes to make any
abnormalities on the surface of your cornea more visible. The drops contain a
yellow dye called fluorescein, which will wash away your tears. Additional
drops may also be put in your eyes to allow your pupils to dilate, or get
The doctor will use a low-powered microscope, along with a slit lamp, which
is a high-intensity light. They will look closely at your eyes. The slit lamp has
different filters to get different views of the eyes. Some doctor’s offices may
have devices that capture digital images to track changes in the eyes over
During the test, the doctor will examine all areas of your eye, including
- optic nerve
The doctor will first examine the front areas of your eye and then perform
the exam again with a different lens to examine the back of your eye.
What does this exam
A slit lamp exam can help diagnose the following conditions:
- macular degeneration, a chronic
condition affecting the part of the eye that is responsible for central
- detached retina, a condition when
the retina, which is an important layer of tissue at the back of the eye,
becomes detached from its base
- cataracts, a clouding of
the lens that negatively affects the ability to see images clearly
- injury to the cornea, an injury to one
of the tissues that covers the surface of the eye
- blockages of the retinal vessel, obstructions in the eye’s blood vessels that can
cause a sudden or gradual loss of vision
Ask your doctor what they are looking for during the exam and which eye
conditions you may be at risk for.
to expect after the exam
Typically, there are no significant side effects of this exam. Your eyes may
be sensitive to light for a while afterward, especially if your pupils were
dilated. If you start feeling nauseous or have eye pain, return to your
doctor’s office as soon as possible. These may be symptoms of increased
pressure of the fluid in the eye, which may be a medical emergency. While the
risk of this is small, the eye drops used to dilate the eye can rarely cause
this to occur.
do abnormal results mean?
If the results of your slit lamp exam are abnormal, a variety of conditions
may be present, including:
- increased pressure in the eye
- degeneration of the arteries or veins in the eye
For example, if macular degeneration is taking place, the doctor may find
drusen, which are yellow deposits that can form in the macula early on in
age-related macular degeneration. If your doctor suspects a particular cause of
vision problems, they may recommend further testing to get a more definitive