Which diagnostic test is used to evaluate tear production in suspected keratoconjunctivitis sicca?

Which diagnostic test is used to evaluate tear production in suspected keratoconjunctivitis sicca?

• A. Fluorescein dye test
• B. Tonometry
• C. Schirmer tear test
• D. Ophthalmoscopy

Answer: (C)

Measuring tear production directly is essential when keratoconjunctivitis sicca is suspected. The Schirmer tear test accomplishes this by placing a standardized absorbent strip in the lower eyelid fornix for a set time (usually one minute) and then measuring how many millimeters of the strip become wetted. This gives a direct readout of aqueous tear production: a shorter wetted length indicates reduced tear production, supporting the diagnosis of dry eye. Other tests don’t assess tear volume. The fluorescein dye test highlights corneal ulcers or staining patterns and helps evaluate tear film stability, but it doesn’t quantify how much tear fluid is produced. Tonometry measures intraocular pressure, and ophthalmoscopy examines the internal structures of the eye; neither assesses tear production.

Measuring tear production directly is essential when keratoconjunctivitis sicca is suspected. The Schirmer tear test accomplishes this by placing a standardized absorbent strip in the lower eyelid fornix for a set time (usually one minute) and then measuring how many millimeters of the strip become wetted. This gives a direct readout of aqueous tear production: a shorter wetted length indicates reduced tear production, supporting the diagnosis of dry eye.

Other tests don’t assess tear volume. The fluorescein dye test highlights corneal ulcers or staining patterns and helps evaluate tear film stability, but it doesn’t quantify how much tear fluid is produced. Tonometry measures intraocular pressure, and ophthalmoscopy examines the internal structures of the eye; neither assesses tear production.