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Glaucoma is a progressive eye disease. It affects three million Americans and is the second leading cause of blindness in the United States. There are two major types of glaucoma: primary open angle glaucoma (POAG) and angle closure glaucoma. The most common type, POAG, will be the focus of this discussion. Angle closure glaucoma, though less common, is considered a medical emergency. Angle closure glaucoma may result in sudden loss or blurring of vision, significantly elevated eye pressures, nausea and vomiting. Both types of glaucoma may result in optic nerve damage and permanent blindness if not treated. Glaucoma does not cause symptoms in the majority of patients. It is important for pharmacists to counsel patients about routine eye examinations and glaucoma screenings for early detection. There are several risk factors associated with the development of glaucoma. These include age >40 years, African American or Asian race, diabetes, hypertension, elevated intraocular pressure, myopia, and family history in a first-degree relative. Treatment is aimed at reduction in intraocular pressure. Eye drops and surgery are the most common treatments. The most potent eye drops are the prostaglandin analogs. The pharmacist's role in the care of patients with glaucoma includes disease and medication counseling, review of eye drop administration technique, eye drop adherence evaluations, and recommendations for routine eye examinations.1,2
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Diagnosis and Clinical Presentation
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Patients with glaucoma usually do not report symptoms until substantial visual field destruction occurs. Visual field loss occurs in 8% to 20% of patients despite reaching therapy goals. Eighty percent of patients without treatment will develop bilateral blindness. Patients with glaucoma may be involved in a motor vehicle accident because they have blind spots related to peripheral vision field defects. Elderly patients with long-standing glaucoma often experience declining vision, headaches, and eye pain.3 Some elderly patients continue to use eye drops even after blindness develops to decrease the incidence of eye pain. Glaucoma can be distinguished from other eye diseases, affecting the optic nerve, by performing a dilated eye examination. Ophthalmologists may note during examination that the rim of the optic nerve is thinning. This thinning is caused by loss of retinal nerve cells. The pink color of the eye fields will remain. Other neuropathies of the optic nerve are characterized by loss of the pink color. Optic nerve thinning results in an enlarged cup-to-disc ratio, which is a hallmark visual finding during examination of the eye. The optic disc is the anatomical location where the optic nerve and blood vessels enter the retina. The optic disc can be flat or it can have a certain amount of normal cupping. In glaucoma, increased pressures cause pathological cupping of the optic disc. The pink disc contains nerve fibers. The white cup is a pit with no nerve fibers. As glaucoma advances, the cup enlarges to cover most of the disc. A normal value for the cup-to-disc ratio is 0.3. A greater value indicates glaucoma. Intraocular pressure (IOP) ...