Eye Conditions in Older Adults: Open-Angle Glaucoma.

Glaucoma is the leading cause of irreversible vision loss in the United States, affecting 1.9% of individuals older than 40 years. The prevalence of the most common form, open-angle glaucoma, increases with age and is higher in non-Hispanic minorities. The progressive loss of peripheral vision in glaucoma often leads to difficulty with driving, particularly at night, and can increase the risk of falls and subsequent fractures. Although glaucoma usually is characterized by chronically elevated intraocular pressure, it is more accurately defined as an optic neuropathy. Typically, there are no warning signs or symptoms, and extensive and permanent optic nerve damage can occur before the patient is aware of visual field loss. A cup to disc ratio greater than 0.6 on ophthalmoscopy is suspicious for glaucoma, and visual field testing results show a characteristic peripheral loss. Medical and surgical treatments are aimed at decreasing intraocular pressure by decreasing production of aqueous humor and increasing its outflow. Drugs for glaucoma treatment include prostaglandin analogs, beta blockers, alpha2-adrenergic agonists, and carbonic anhydrase inhibitors. Surgical or laser treatment is indicated if medical management is unsuccessful. Alternative therapies are less effective and have more adverse effects than standard treatments.

Eye Conditions in Older Adults: Cataracts.

A clinically significant cataract is defined as an opacification of the eye lens causing a significant decrease in visual acuity or a functional visual impairment. Age-related cataracts are the leading cause of blindness in the world and one of the most common etiologies of visual impairment in the United States. Consequences can include loss of driving privileges, inability to read or watch television, inability to participate in social activities, and an increased risk of falls. In the United States, cataract surgery is the most commonly performed surgical procedure among older patients. There are three main types of cataracts: nuclear, cortical, and subcapsular. Age is the strongest predictor of cataract development. Other major risk factors include a family history of cataracts, diabetes, smoking, obesity, poor nutrition, lower socioeconomic status, and alcohol use. Surgery is the definitive treatment. Phacoemulsification and implantation of a posterior chamber intraocular lens is the most common method used for managing cataracts in the United States. Glasses or contact lenses then are prescribed to correct any residual refractive errors. Cataract surgery is a low-risk procedure and routine preoperative testing typically is not needed.

Eye Conditions in Older Adults: Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) causes a progressive loss of photoreceptors in the macula. It is the most common cause of legal blindness in the United States, and some form of AMD is thought to affect more than 9 million individuals. Risk factors include older age, smoking, dyslipidemia, obesity, white race, female sex, and a family history of AMD. There are two types of advanced AMD: nonexudative (dry or geographic atrophy) and exudative (wet or neovascular). Both cause progressive central vision loss with intact peripheral vision. Nonexudative AMD accounts for 80% to 90% of all advanced cases, and more than 90% of patients with severe vision loss have exudative AMD. On ophthalmoscopic examination, early findings include drusen (ie, yellow deposits in the retina). Prominent choroidal vessels, subretinal edema, and/or hemorrhage are seen in wet AMD. Regular eye examinations, visual field testing, fluorescein angiography, and optical coherence tomography are used for diagnosis and to guide management. There is no specific therapy for dry AMD, but antioxidant supplementation may be helpful. Intravitreal injection of a vascular endothelial growth factor inhibitor is the treatment of choice for wet AMD. Optical aids and devices can help to maximize function for patients with AMD.

Eye Conditions in Older Adults: Diabetic Retinopathy.

Diabetic retinopathy is related to neovascularization of the retina stimulated by an elevated blood glucose level. This can lead to macular edema, vascular hemorrhage, retinal detachment, and neovascular glaucoma. Diabetic retinopathy is a leading cause of blindness in the United States, and is estimated to affect between 28% and 40% of patients older than 40 years. Significant visual deficit from diabetic retinopathy can lead to social isolation of older individuals by limiting driving, the ability to leave the home or remain in the home safely, and the ability to watch television or read. Primary and secondary prevention includes adequate control of A1c levels. Screening is important for early detection of ocular damage and intervention. Retinal benefits of therapy may predict cardiovascular benefits over a longer period.

Harold Knapp and the geography of normal controversy: radioiodine in the historical environment.

In 1962, after high levels of the isotope Iodine-131 were detected in Utah milk supplies, Dr. Harold Knapp, a mathematician working for the AEC's Division of Biology and Medicine, developed a new model of estimating, first, the relation between a single deposition of radioactive fallout on pasturage and the levels of Iodine-131 in fresh milk and, second, the total dose to human thyroids, resulting from daily intake of the contaminated milk. The implications of Knapp's findings were enormous. They suggested that short-living radioiodine, rather than long-living nuclides such as radiostrontium, posed the greatest hazard from nuclear test fallout and that children raised in Nevada and Utah during the 1950s had been exposed to internal radiation doses far in excess of recommended guidelines. This paper explores the explicit historical revisionism of Knapp's study, his refusal, contra normal AEC practices of knowledge production and spatial representation, to distance himself from the people and places downwind from the Nevada Test Site, and the reactions his work provoked among his AEC colleagues.