How to Use Slit Lamps to Measure IOP

Eye-care professionals use a slit lamp to examine eye health. The instrument, which also is called a biomicroscope, magnifies an eye so the doctor or optometrist can examine its external and internal structures thoroughly. Slit lamps are used routinely to diagnose many eye problems, including cataracts, corneal ulcers and diabetic retinopathy. They also are used with special attachments to measure intraocular pressure (IOP). High pressure in an eye leads to ocular hypertension and sometimes glaucoma.

Things You'll Need

• Goldmann tonometer attachment
• Anesthetic drops

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Instructions

• 1

  Set a slit lamp's eye pieces by inserting the focusing rod into place at the front of the microscope. Direct the slit lamp beam to the center of the focusing rod's flat end. Set each eye piece by focusing it on the rod until the image is focused sharply.

• 2

  Attach a Goldmann tonometer to the slit lamp if if doesn't already have that tonometer. For the typical eye exam, attach 10x eye pieces, and turn the slit lamp to the lowest powered objective, 1x.

• 3

  Ask the patient to sit in front of the slit lamp and place his chin on the chin rest. Adjust the slit lamp so the patient's eyes are level with the black mark on the face rest. Turn on the slit lamp, and shine the light toward one of the patient's eyes. Look through the ocular lenses to observe the eye while instructing the patient to move and turn his eyes in each direction for better examination.

• 4

  Place two drops of anesthetic in each of the patient's eyes before continuing the examination. The drops lubricate the eyes and prevent irritation during and after the procedure.

• 5

  Swing the arm of the Goldmann tonometer attachment into place. Place the prism mounted on the tonometer head lightly against the patient's cornea. It flattens the cornea, allowing you to measure the eye's IOP. Using the device's cobalt filter, observe the green semicircles and adjust the dial to control the variable tension spring until inner edges of the green semicircles in the viewfinder meet.

• 6

  Record the measurement in the patient's chart once the procedure has been completed properly.