What are typical signs of conjunctivitis in horses?

• A. Severe corneal edema and blinking.
• B. Absence of discharge with normal conjunctiva.
• C. Red, swollen conjunctiva with mucopurulent discharge and minimal corneal pain.
• D. Pupil dilation and photophobia only.

Answer: (C)

Conjunctivitis in horses mainly presents as inflammation of the conjunctiva with redness and swelling of the conjunctival tissue, often accompanied by discharge from the surface. The key feature here is that the conjunctiva is inflamed and producing mucus or pus, while the cornea itself is not the primary site of involvement and tends to have only mild or no pain unless the disease spreads.

Red, swollen conjunctiva with mucopurulent discharge reflects active conjunctival inflammation and glandular/excretory irritation, which fits conjunctivitis well. The pain associated with the cornea remains minimal in uncomplicated conjunctival disease, so you don’t typically see strong signs of corneal pain or edema in this scenario.

Other options describe findings that point away from conjunctivitis. Severe corneal edema and blinking indicate corneal involvement, such as keratitis or corneal ulcers. Absence of discharge with a normal conjunctiva means there isn’t conjunctival inflammation. Pupil dilation and photophobia alone suggest deeper ocular pain, like uveitis or significant corneal disease, rather than primary conjunctivitis.

So, the combination of red, swollen conjunctiva with mucopurulent discharge and minimal corneal pain best matches typical conjunctivitis signs in horses.