This patient has acute closed-angle glaucoma, as evidenced by the pain and redness of her eye, the steamy cornea, her description of halos around lights, and her markedly elevated intraocular pressure. The fixed mid-dilated pupil indicates ischemia to the iris. Unlike open angle glaucoma, closed-angle glaucoma (also called narrow-angle or angle-closure glaucoma) is a medical emergency, and requires immediate diagnosis and treatment to prevent permanent visual impairment. The anterior and posterior chambers of the eye are filled with aqueous humor, which flows from the posterior chamber, through the pupil, into the anterior chamber, into the trabecular network, and then exits the eye the canal of Schlemm. Individuals with a shallow or narrow anterior chamber or thickened lens may be predisposed to this type of glaucoma because their iris is in close opposition to the chamber angle and cornea (narrow angle). If the aqueous humor is produced at a greater rate than it can be drained, intraocular pressure rises. Any stimulus that causes pupillary dilation (e.g., anticholinergic medications, sympathomimetics, emotional upset, dim lighting) can precipitate an attack. The cornea may look hazy because of edema, but corneal laceration is produced by trauma. There is no history of trauma in this patient and the symptoms exhibited by this patient strongly suggest acute closed-angle glaucoma. Intraocular hypeension is a condition in which IOP is higher than normal (greater than 21 mm Hg), but there is no damage to the optic nerve or visual loss. About 90% of people with elevated IOP never develop glaucoma. There is no associated pain or visual symptoms associated with this. Known as the "sneak thief of sight," open-angle glaucoma has no early warning signs or symptoms, and accounts for 90% of all glaucoma cases. It is a slow progressive condition, usually affecting both eyes, in which there is an increase in resistance to the outflow of aqueous humor. This resistance is associated with a normal rate of production of the fluid and normal anterior chamber angle. Elevated IOP is the most common finding and age-related changes in the trabecular region are the most likely explanation of this disease.