Glaucoma refers to a group of eye conditions that lead to damage to the optic nerve. It is an insidious and painful disease that often results in blindness in the affected eye. Glaucoma can be congenital, primary or secondary.

Congenital. A rare condition affecting foals which results in a rapid globe enlargement.

Secondary. The secondary form of glaucoma is the most common type that affects horses. It is caused by concurrent intraocular diseases such as chronic uveitis, intraocular neoplasia, or retinal detachment.