What characterizes the eye during an acute glaucoma attack?

During an acute glaucoma attack, the eye is characterized by a painful sensation and mydriasis, which is the dilation of the pupil. This occurs due to increased intraocular pressure that is typical in glaucoma. The pain is often severe, prompting the animal to exhibit signs of discomfort, such as rubbing at the eye or keeping it closed.

Mydriasis results from the muscle fibers in the iris being affected by the elevated pressure and possibly also by a reflex response to pain. In such cases, the affected eye may appear red and the cornea can become hazy due to edema. The other characteristics of an acute glaucoma attack, such as significant tear production, are not consistently present; in fact, the opposite can occur where tear production may actually decrease. Normal pupil size is not expected, as mydriasis is closely associated with this condition. Pupillary constriction would imply a different issue, often associated with other eye conditions that are not characterized by acute glaucoma.