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in medicine, opacity of the lens of the eye, which impairs vision. In the young, cataracts are generally congenital or hereditary; later they are usually the result of degenerative changes brought on by aging or systemic disease (diabetesdiabetes
or diabetes mellitus
, chronic disorder of glucose (sugar) metabolism caused by inadequate production or use of insulin, a hormone produced in specialized cells (beta cells in the islets of Langerhans) in the pancreas that allows the body to use and store
..... Click the link for more information.
). Cataracts brought on by aging are most common; most individuals over 60 exhibit some degree of lens opacity. Injury, extreme heat, ultraviolet light, X rays, nuclear radiation, inflammatory disease, and toxic substances also cause cataracts. There is growing concern that further disintegration of the ozone layerozone layer
or ozonosphere,
region of the stratosphere containing relatively high concentrations of ozone, located at altitudes of 12–30 mi (19–48 km) above the earth's surface.
..... Click the link for more information.
 will increase the incidence of cataracts. Advanced cataracts are usually treated by surgical removal of the lens and implantation of an artificial lens. After cataract surgery, which is the most common surgical procedure in the United States, most patients do not require thick glasses or contact lenses.



an opacity of the crystalline lens of the eye that prevents light from penetrating into the eye and that results in decreased visual acuity. The term “cataract” reflects the mistaken conception of the ancient Greeks that a cataract is caused by the effusion of a turbid fluid between the iris and the lens. Cataracts are distinguished according to the location of the opacity in the lens: capsular (in the capsule covering the lens), cortical (in the peripheral layers of the lens), and nuclear (in its central layers).

Cataracts may be congenital or acquired. Congenital cataracts develop in the intrauterine period, and the opacity generally does not enlarge or change with age. In congenital cataracts, parts of the lens almost invariably remain transparent, and visual acuity is not completely impaired. Depending on the site of the opacities, cataracts may be anterior or posterior polar (limited opacities of the capsule of the lens), lamellar, and so forth.

Senile cataracts constitute most of the acquired cataracts, and they are characterized by progression of the opacities of the lens. In senile cataracts, opacities appear first in the periphery of the lens (incipient senile cataract), and vision remains unimpaired. The number of opacities then increases and they coalesce, resulting in a marked decrease in visual acuity (immature cataract). As the condition develops, all the layers of the lens become cloudy and it turns grayish white or mother-of-pearl; visual acuity decreases to photoperception—that is, the eye becomes virtually blind (mature senile cataract). Also acquired are complicated cataracts that arise in some systemic diseases (diabetes, cholera, digestive disorders) or result from diseases of the eye itself (inflammation of the uveal tract, progressive myopia). Cataracts resulting from eye injuries, effects of radiation, and so forth constitute a large group of acquired cataracts.

Treatment is generally surgical. In some cases it involves transplanting an artificial lens.


Dymshits, L. A. “Bolezni khrustalika.” In Mnogotomnoe rukovodstvo po glaznym bolezniam, vol. 2, book 2. Moscow, 1960.



A waterfall of considerable volume with the vertical fall concentrated in one sheer drop.
An opacity in the crystalline lens or the lens capsule of the eye.


1. a large waterfall or rapids
2. Pathol
a. partial or total opacity of the crystalline lens of the eye
b. the opaque area
References in periodicals archive ?
Julie Mares, PhD, of the University of Wisconsin in Madison, and colleagues followed nearly 2,000 women aged 55 to 86 and compared their answers on a food questionnaire to their development of nuclear cataracts.
dietary guidelines at the time of entry in the Women's Health Initiative study, are more strongly related to the lower occurrence of nuclear cataracts than any other modifiable risk factor or protective factor studied in this sample of women," the study said.
Buphthalmos (congenital glaucoma with corneal clouding) and bilateral nuclear cataracts were also seen (as shown in fig-2, C&D).
Smoking is considered a significant risk factor for the development of nuclear cataract, with the research literature demonstrating a clear dose response.
The post-vitrectomy cataract that forms as a result of oxidative damage is a nuclear cataract, the same as the more common age-related cataract, which affects as many as 35 million Americans.
The use of a slit-lamp optical section technique is the only accurate way of detecting and assessing nuclear cataract and it is best performed with a dilated pupil, although is still possible undilated.
sup][10] found a similar 10% decrease in endothelial cell count after phacoemulsification and conventional ECCE; the authors suggested that ECCE was preferred over phacoemulsification for hard nuclear cataracts removal, given that phacoemulsification caused greater endothelial cell loss rate than ECCE in such cases.
In particular, the multi seemed to lower the risk of nuclear cataracts, the most common (though not the most serious) type.
Statins, particularly simvastatin, appear to lower the risk of nuclear cataracts, the most common type of age-related cataracts, results of a large, prospective study suggest.
Research was conducted on 445 men aged over 50, 79 of whom were airline pilots and 71 were found to have nuclear cataracts, leading researchers to conclude that the pilots had triple the risk of developing cataracts when compared to other survey participants.
Smoking greatly increases your risk of getting nuclear cataracts, the most common type of cataracts in the U.