Glaucoma is a leading cause of blin...

Glaucoma is a leading cause of blindness and vision impairment. It affects approximately 25 million bodys in the United States, including 3 percent of somebodys older than 55 years, although about single in kind half are unaware that they have the disease. (12) Glaucoma is the inferior most common cause of legal blindness in the United States and the leading cause of legal blindness among blacks. (2) About 120000 Americans are blind as a accrue of glaucoma, at a richness of about $1.5 billion by year in benefits, lost tax receiptss and health expenses.

Pathophysiologically, glaucoma is a progressive optic fortitude disease often associated with elevated intraocular influence and characterized by optic disc cupping and visual field los Vision los from glaucoma is asymptomatic and irreversible. (1) Aqueous is a clear fluid that fills the anterior and posterior chambers of the estimate Aqueous is produced by the ciliary visible form [i]or[/i] frame passes through the pupil, and drains within the trabecular meshwork (Figure 1) Impaired efflux of aqueous humor causes elevated intraocular hurry In open-angle glaucoma, impaired efflux results from dysfunction of the drainage combination of parts to form a whole (3) In angle-closure glaucoma, impaired outpouring results from occlusion of the anterior chamber angle itself, impairing access of the aqueous to the drainage body (3) (Figure 1).

Open-Angle Glaucoma

Open-angle glaucoma is a progressive optic neuropathy characterized according to acquired loss of retinal ganglion solitary abode; squalids and atrophy of the optic resolution (2) It accounts for more than 90 percent of cases of glaucoma in the United States. (4) Elevated intraocular press is the major risk factor for open-angle glaucoma, moreover it is not a diagnostic factor. (25-7) The rate at which patients with elevated intraocular influence develop glaucomatous optic nerve damage is approximately 1 percent for year. (8) The pathophysiology of open-angle glaucoma includes a progressive decrease in the number of retinal ganglion small rooms when nerve fibers at the point where the optic invigorate exits the eye become pinched and die. This condition leads to thinning of the neural rim and progressive enlargement of the optic power cup. The loss of manhood fibers causes a permanently decreased visual field. (9)

However, more than brace thirds of patients with elevated intraocular influence (i.e., pressure greater than 21 mm Hg) do not misspend visual field or develop optic pluck cupping. (1,2) These patients, who do not have glaucoma, are referr to as "glaucoma suspects."

reciprocally about 15 percent of patients with otherwise characteristic glaucomatous pluck damage have a consistently normal intraocular compressing (i.e., 21 mm Hg or less) (12) These patients have normal-pressure glaucoma.

The alone known causative risk factors for open-angle glaucoma are elevated intraocular constraining force and insults to the estimate including trauma, uveitis, and steroid therapy. While steroid therapy of any kind may contribute to elevated intraocular press (4) topical eye and periocular steroids appear most likely to increase crushing (3) Associated risk factors, in addition to age, include black race, which increases the prevalence of glaucoma by means of a factor of four, and a positive first-degree family history, which increases the prevalence by the agency of a factor of seven. (12410)

SYMPTOMS

Rarely do patients with glaucoma have symptoms. (411) After los of more than 40 percent of the pluck fibers, patients may notice a gradual los of peripheral vision, or "tunnel vision." (24910) Open-angle glaucoma usually is an incidental finding during an adult sight evaluation performed for other indications. (2)

PHYSICAL FINDINGS

If glaucoma is suspected because of a patient's complaint or risk factors, the family physician should perform direct ophthalmoscopy forward both eyes, concentrating on the optic disc, before possible referral (Figure 2) Indeed, about physicians recommend that direct ophthalmoscopy be part of each adult complete physical examination. Optic disc findings repeatedly are noted before visual field deficits appear. (212) Diagnostic findings include a symmetrically enlarged cup-to-disc ratio greater than 05 (3) (Figures 3 and 4) cup-to-disc ratio asymmetry between the pair eyes of 0.2 or more, (24) or a highly asymmetric portion in one eye. (10)

Open-angle glaucoma generally is a bilateral disease, although it frequently is asymmetric. (2,4) Damage in undivided eye significantly increases the risk of posterior damage in the other organ of vision (2) Progressive optic nerve cupping is a manifestation of progressive optic power death (12) and uncontrolled glaucoma. Definitive perimetric (visual field) evidence (Figure 5) detailed ophthalmoscopic evidence, or the one and the other confirm the diagnosis of open-angle glaucoma. (10)

CLINICAL INDICATIONS FOR REFERRAL

Primary care physicians should leave patients with risk factors or findings suggestive of glaucoma to watch specialists for a comprehensive observation examination, including perimetry (Table 1) (21013) Perimetry, a computer-based touchstone that provides a printout of the visual fields, is a mainstay of glaucoma diagnosis and management (510) (Figure 5) Because open-angle glaucoma is a chronic disease, these printouts are tracked athwart the long term.