is a disease that is often associated with elevated intraocular pressure, damage to the optic nerve and vision loss.
There are several forms of glaucoma; the two most common forms are acute glaucoma (angle closure) and chronic glaucoma (open angle).
In acute glaucoma (angle closure), the onset is often sudden with severe pain, the eye is red, the pupil is large and either circular or oval, there is corneal edema and the intraocular pressure is high.
Patients with acute glaucoma usually seek treatment immediately because of extreme pain and blurred vision. The blurred vision is associated with halos around lights. Nausea and abdominal pain may occur.
If untreated, acute glaucoma can lead to blindness.
Chronic glaucoma (open-angle type) is the most common form of glaucoma. It is characterized by a gradual loss of vision with damage to the optic nerve and loss of visual fields beginning usually at the periphery (tunnel vision).
Elevated intraocular pressure (IOP) is seen in up to 80% of cases and is due to reduced drainage of aqueous through the trabecular meshwork.
Risk factors include age over 65, African American origin, diabetes mellitus, myopia, family history of glaucoma, and ocular hypertension (IOP ≥ 21 mm Hg).