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Chapter 029. Disorders of the Eye (Part 15)

Glaucoma results in "cupping" as the neural rim is destroyed and the central cup becomes enlarged and excavated. The cup-to-disc ratio is about 0.7/1.0 in this patient. In acute angle-closure glaucoma, the eye is red and painful due to abrupt, severe elevation of intraocular pressure. Such cases account for only a minority of glaucoma cases: most patients have open, anterior chamber angles. The cause of raised intraocular pressure in open angle glaucoma is unknown, but it is associated with gene mutations in the heritable forms. Glaucoma is usually painless (except in angle-closure glaucoma). Foveal acuity is spared until end-stage disease is. | Chapter 029. Disorders of the Eye Part 15 Glaucoma results in cupping as the neural rim is destroyed and the central cup becomes enlarged and excavated. The cup-to-disc ratio is about 0.7 1.0 in this patient. In acute angle-closure glaucoma the eye is red and painful due to abrupt severe elevation of intraocular pressure. Such cases account for only a minority of glaucoma cases most patients have open anterior chamber angles. The cause of raised intraocular pressure in open angle glaucoma is unknown but it is associated with gene mutations in the heritable forms. Glaucoma is usually painless except in angle-closure glaucoma . Foveal acuity is spared until end-stage disease is reached. For these reasons severe and irreversible damage can occur before either the patient or physician recognizes the diagnosis. Screening of patients for glaucoma by noting the cup-to-disc ratio on ophthalmoscopy and by measuring intraocular pressure is vital. Glaucoma is treated with topical adrenergic agonists cholinergic agonists beta blockers and prostaglandin analogues. Occasionally systemic absorption of beta blocker from eye drops can be sufficient to cause side effects of bradycardia hypotension heart block bronchospasm or depression. Topical or oral carbonic anhydrase inhibitors are used to lower intraocular pressure by reducing aqueous production. Laser treatment of the trabecular meshwork in the anterior chamber angle improves aqueous outflow from the eye. If medical or laser treatments fail to halt optic nerve damage from glaucoma a filter must be constructed surgically trabeculectomy or a valve placed to release aqueous from the eye in a controlled fashion. Macular Degeneration This is a major cause of gradual painless bilateral central visual loss in the elderly. The old term senile macular degeneration misinterpreted by many patients as an unflattering reference has been replaced with age-related macular degeneration. It occurs in a nonexudative dry form and an exudative .