Q: I am looking for information on glaucoma in foals. Any information will be helpful.

—Kelly

A: Glaucoma is a disease characterized by an increase in pressure within the eye that is higher than the eye can tolerate. Glaucoma causes blindness from damage to the optic nerve and retina (the structures that collect light and transmit visual signals to the brain).

Three types of glaucoma occur in horses: 1) Primary glaucoma occurs when pressure in the eye increases, but there is not an obvious ocular (eye-related) cause; 2) Secondary glaucoma occurs because of the presence of other diseases in the eye, such as inflammation or cancer; and 3) Neonatal glaucoma occurs soon after birth in a foal