Patient Care

Schirmer's Test

Schirmer's test determines whether the eye produces enough tears to keep it moist.

Schirmer's test uses paper strips inserted into the eye for several minutes to measure the production of tears. The exact procedure may vary somewhat. Both eyes are tested at the same time. Most often, this test consists of placing a small strip of filter paper inside the lower eyelid (conjunctival sac). The eyes are closed for 5 minutes. The paper is then removed and the amount of moisture is measured. Sometimes a topical anesthetic in placed into the eye before the filter paper to prevent tearing due to the irritation from the paper.

Keratometry measures the corneal curvature.  It is performed for similar reasons as topography, but rather than mapping the entire corneal surface, two curves are measured – the steepest and the flattest.  These measurements give the doctor information about the cornea’s curvature, focusing power, and whether astigmatism is present. 

Some of the uses of keratometry include calculating the intraocular lens power for cataract surgery, fitting contact lenses and monitoring the corneal curvature after surgery.

Corneal topography is a method of corneal curvature examination assisted by computer analysis. A corneal topographer projects a series of illuminated rings onto the corneal surface, which are reflected back into the instrument. The reflected rings of light are analyzed by the computer and a topographical map of the cornea is generated. The topographical map and computerized analysis reveals any distortions of the cornea, such as is keratoconus or corneal scarring, as well as the corneal curvature and meridians of astigmatism. This diagnostic procedure is essential for patients being considered for refractive surgical procedures (such as LASIK) and may even be necessary in the follow-up of some patients who have undergone refractive surgical procedures.