Patient Care

Slit Lamp Examination

The slit lamp is a microscope with a light attached that allows the doctor to examine your eye under high magnification.  This instrument is primarily used to view the anterior structures of the eye such as the cornea, iris, and lens.  However, with special lenses, it is possible to examine the vitreous and the back of the eye as well. 

The instrument’s name is derived from its adjustable light beam.  By changing the width of the beam, the doctor can gather important detail about each eye structure.  The next time you accompany a family member to an eye exam, ask to look in the slit lamp.

A tonometry test measures the pressure inside your eye, which is called intraocular pressure (IOP). This test is used to help detect glaucoma, a group of eye diseases that can cause blindness by damaging the nerve in the back of the eye (optic nerve). Damage to the optic nerve may be caused in part by fluid that fails to drain properly out of the eye.

Tonometry measures IOP by determining the resistance of your cornea to indentation. Eyedrops to numb the surface of your eye are used with most of the methods used to measure IOP.

This type of tonometry uses a plunger to indent your cornea. The pressure within your eye is determined by measuring how much your cornea is indented by a given weight. This test is less accurate than applanation tonometry and is less commonly used today by ophthalmologists and optometrists. However, other doctors, such as family medicine doctors or urgent care doctors, may still commonly use this test.

This type of tonometry uses a special probe to flatten part of your cornea to measure eye pressure and a microscope called a slit lamp to examine your eye. The pressure within your eye is determined by how much weight is needed to flatten your cornea. This type of tonometry is very accurate and is often used to measure IOP after a simple screening test (such as air-puff tonometry) detects increased IOP.