Schirmer tear testing is especially recommended in which condition?

• A. Equine with cataracts
• B. Temporohyoid osteoarthropathy
• C. Equine with glaucoma
• D. Equine with uveitis

Answer: (B)

Schirmer tear test measures aqueous tear production, allowing you to detect a deficiency in tear output that can leave the cornea vulnerable. In temporohyoid osteoarthropathy, the facial nerve (cranial nerve VII) can be affected, leading to reduced lacrimal secretion. Because dry eye increases the risk of corneal drying and ulcers in these horses, testing tear production is particularly informative and helps guide management with lubricants and monitoring. The other conditions listed aren’t primarily defined by tear production problems—cataracts and glaucoma affect intraocular structures and pressure, while uveitis is an inflammatory process that isn’t inherently indicated by tear output measurement—so Schirmer testing is most clinically relevant for THO.