Chronic glaucoma, also called open-angle glaucoma, is an eye condition in which the optic nerve is damaged over time, causing gradual loss of vision and, if left untreated, blindness. Chronic glaucoma is typically caused by a combination of eye defects or diseases that raise intraocular pressure, or pressure inside the eye. This rise in intraocular pressure usually causes the damage to the optic nerve, though there are certain forms of glaucoma that occur despite normal eye pressure. As it happens slowly and painlessly, people often fail to notice any symptoms of chronic glaucoma until their vision has been significantly and permanently harmed. Though the condition cannot be cured and vision loss cannot be reversed, treatment can help deter further vision loss.
Chronic glaucoma is glaucoma that develops progressively, as opposed to acute glaucoma, which has a sudden onset. Typically, chronic glaucoma is associated with primary open-angle glaucoma. In this condition, the aqueous humor of the eye, or the naturally produced fluid of the eye, fails to drain fast enough, leading to a build-up of pressure in the eye. Normally, the aqueous humor drains out of the eye through an angle at the meeting point of the cornea and the iris. In chronic glaucoma, the tiny passageways in this angle are progressively narrowed, for unknown reasons, causing a slow rise in intraocular pressure. This pressure causes damage to the optic nerve so gradually that people often don’t realize there’s a problem until much of their vision has already been lost.
Angle-closure glaucoma is usually thought of as an acute form of the disease, but it can also be a chronic glaucoma. In this type of the disease, the iris shifts or expands forward to narrow or close the angle formed by the iris and cornea, so that the aqueous humor cannot drain properly. Low-tension glaucoma can also be acute or chronic and occurs when the optic nerve becomes damaged despite a normal intraocular pressure. This could be due to blockages in the arteries that feed the nerve. Glaucoma can also arise due to a birth defect of the eye, called congenital glaucoma, or because pigmentary granules get jostled, such as during sports, and become lodged in the drainage system.
Symptoms of chronic glaucoma often don’t present themselves until a very advanced stage of the disorder, but can include spots of vision loss in peripheral vision and total loss of peripheral vision, or tunnel vision. Acute glaucoma tends to present more noticeable symptoms, such as redness of the eye, eye swelling, clouded vision, pain in the eye, and seeing halos around lights. As the loss of vision from glaucoma is permanent, patients should get treatment as soon as symptoms arise and get regular exams, especially if they have any risk factors. Risk factors include advancing age, being of African descent, diabetes, hypothyroidism, family history of glaucoma, nearsightedness, high intraocular pressure, history of eye injuries, and history of prolonged corticosteroid use.
Treatment for chronic glaucoma does not cure the condition or reverse vision loss, but it can help prevent future damage. A doctor might prescribe eye drops to relieve eye pressure, pills to achieve the same effect, or surgery to open up the drainage system in the narrowed angle. Surgery is usually performed as a painless laser surgery on an outpatient basis.