What Is a Slit-Lamp Exam Used For?

Published on May 25, 2021 ​​​​​​​

When you pay a visit to your eye doctor, he will not just check to determine whether you can see the eye chart clearly. The doctor will also use a slit lamp to ensure your eyes are healthy. Eye diseases can be difficult to diagnose during a regular physical exam. Ophthalmologists diagnose and examine certain eye conditions using a variety of specialized tools. During a comprehensive eye examination, your eye doctor will likely give you a slit-lamp exam.


What Is a Slit-Lamp Exam?


This is a standard diagnostic procedure also called biomicroscopy. This exam combines a very bright light with a microscope. You sit in a chair facing a microscope with a bright light, with your forehead and chin resting on a support. The eye doctor then uses this instrument to examine your eyes in detail to determine whether they have any problems or abnormalities. 


What Happens During the Exam?


Before you go for a slit-lamp exam, you do not need to make any preparations. Once you are in the eye doctor’s examination chair, he will place a slit lamp in front of you and ask you to rest your forehead and chin on the supports. The doctor may apply eye drops containing a dye known as fluorescein. This yellowish dye will wash away your tears. He may also put additional eye drops in your eyes to enlarge and dilate your pupils. 


Next, the doctor will use a slit lamp, along with a low-powered microscope, to examine your eyes closely. Some eye doctors use a special camera to capture digital images of your eyes. These images are important when it comes to tracking changes in your eyes over time. During the slit-lamp exam, the eye doctor will look closely at all areas of your eyes, including:


  • Retina

  • Lens

  • Eyelids

  • Conjunctiva

  • Optic nerve

  • Cornea

  • Iris

  • Sclera


Initially, the eye doctor will examine the front parts of your eyes. He will then use a different lens to examine the back areas of your eyes. 


What Does a Slit-Lamp Exam Diagnose?


Eye doctors use this exam to examine the structures within a patient’s eyes. Before your doctor starts the exam, he will ask you to remove your contact lenses or glasses. This exam can diagnose a variety of eye conditions, such as:


  • Macular degeneration, which is a chronic condition affecting the portion of the eye responsible for central vision.

  • Obstructions in the blood vessels in the eye and blockages in the retinal vessel, which can lead to gradual or sudden loss of vision.

  • Injury to the tissues covering the surface of your eye or an injury to the retina.

  • Cataracts, which can affect your ability to see clearly due to the clouding of the lens.

  • Detached retina.


During the examination, you should ask your eye doctor what he is looking for, as well as the eye condition you are at most risk of developing. Usually, there are no significant side effects of a slit-lamp exam. However, you may experience some light sensitivity for a while.


To learn more about a slit-lamp exam, contact Dau Family Eye Care in St. John’s, Florida at (904) 713-2020 today to schedule an appointment.

132 Everest Ln, Ste 5
St. John's, FL 32259