cataract /cat·a·ract/ (-rakt) an opacity of the crystalline lens of the eye or its capsule.catarac´tous
after-cataract a recurrent capsular cataract.
atopic cataract cataract in those with long-standing atopic dermatitis.
black cataract see senile nuclear sclerotic c.
blue cataract , blue dot cataract blue punctate opacities scattered throughout the nucleus and cortex of the lens.
brown cataract , brunescent cataract see senile nuclear sclerotic c.
capsular cataract one consisting of an opacity in the lens capsule.
complicated cataract secondary c.
congenital cataract 1. cataract present at birth, usually bilaterally; it may be mild or severe and may or may not impair vision depending on size, density, and location.
2. developmental c.

coronary cataract tiny white opacities in a ring around the lens, the center and periphery of the lens remaining clear.
cortical cataract 1. developmental punctate opacity common in the cortex and present in most lenses. The cataract is white or cerulean, increases in number with age, but rarely affects vision.
2. the most common senile cataract; white, wedgelike opacities are like spokes around the periphery of the cortex.

cupuliform cataract a senile cataract in the posterior cortex of the lens just under the capsule.
developmental cataract a type of small cataract in youth, resulting from heredity, malnutrition, toxicity, or inflammation, seldom affecting vision.
electric cataract one occurring after an electric shock, especially to the head. Anterior subcapsular cataracts may form and develop within days; slowly developing or stationary opacities may follow a shock not to the head.
glassblowers' cataract , heat cataract posterior subcapsular opacities caused by chronic exposure to infrared (heat) radiation.
hypermature cataract one with a swollen, milky cortex, the result of autolysis of the lens fibers of a mature cataract.
lamellar cataract one affecting only certain layers between the cortex and nucleus of the lens.
mature cataract one producing swelling and opacity of the entire lens.
membranous cataract a condition in which the lens substance has shrunk, leaving remnants of the capsule and fibrous tissue formation.
morgagnian cataract a mature cataract in which the cortex has liquefied and the nucleus moves freely within the lens.
nuclear cataract one in which the opacity is in the central nucleus of the eye.
overripe cataract hypermature c.
polar cataract one at the center of the anterior (anterior polar c.) or posterior (posterior polar c.) pole of the lens.
pyramidal cataract a conoid anterior cataract with its apex projecting forward into the aqueous humor.
radiation cataract one caused by ionizing radiation, e.g., x-rays, or by nonionizing radiation, e.g., infrared (heat) rays, ultraviolet rays, microwaves.
ripe cataract mature c.
secondary cataract one resulting from disease, e.g., iridocyclitis; degeneration, e.g., chronic glaucoma, retinal detachment; or from surgery, e.g., glaucoma filtering, retinal reattachment.
senile cataract cataract in the elderly.
senile nuclear sclerotic cataract slowly increasing hardening of the nucleus, usually bilateral and brown or black, with the lens becoming inelastic and unable to accommodate.
snowflake cataract , snowstorm cataract one marked by gray or blue to white flaky opacities, seen in young diabetics.
total cataract an opacity of all the fibers of a lens.
toxic cataract that due to exposure to a toxic drug, e.g., naphthalene.
traumatic cataract one due to injury to the eye.
zonular cataract lamellar c.


Dorland's Medical Dictionary for Health Consumers. © 2007 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
cat·a·ract (kCataract definitions abreve.giftCataract definitions prime.gifCataract definitions schwa.gif-rCataract definitions abreve.gifktCataract definitions lprime.gif)n.Opacity of the lens or capsule of the eye, causing impairment of vision or blindness.

catCataract definitions lprime.gifa·racCataract definitions prime.giftous (-rCataract definitions abreve.gifkCataract definitions prime.giftCataract definitions schwa.gifs) adj.
Cataract definitions THDcatara.jpgCataract definitions enlarge.gif

cataractlocation in the lens of different types of cataracts

The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
Cataract
Progressive opacity or clouding of an eye lens, which obstructs the passage of light to the retina.
Mentioned in: Amblyopia, Anticancer Drugs, Cataract Surgery, Corneal Transplantation, Diabetes Mellitus, Electric Shock Injuries,Photorefractive Keratectomy and Laser-Assisted In-Situ Keratomileusis
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
cataract
[kat′ərakt]Etymology: Gk, katarrhakies, waterfall

an abnormal progressive condition of the lens of the eye, characterized by loss of transparency. A yellow, brown, or white opacity can be observed within the lens, behind the pupil. Most cataracts are caused by degenerative changes, often occurring after 50 years of age. The tendency to develop cataracts is inherited. Trauma, such as a puncture wound, may result in cataract formation. Less often, exposure to such poisons as dinitrophenol or naphthalene causes them. Congenital cataracts are usually hereditary but may be caused by viral infection during the first trimester of gestation. If cataracts are untreated, sight is eventually lost. At onset, vision is blurred; then bright lights glare diffusely, and distortion and double vision may develop. Uncomplicated cataracts of old age (senile cataracts) are usually treated with excision of the lens and either surgical insertion of an intraocular lens or prescription of special contact lenses or glasses. The soft cataracts of children and young adults may be either incised and drained or fragmented by ultrasound.observations Symptoms of cataracts include progressive, painless blurring and distortion of objects, glare from bright lights, and gradual loss of vision. Signs include a yellow, brown, or white coloring on the pupil and myopia. The crystalline lens of the eye becomes cloudy and opaque. Cataracts are identified by a complete ophthalmoscopic exam, including funduscopy and slit lamp examination. The primary complication is blindness.
interventions Surgical removal of the lens is the primary treatment and is performed only after vision becomes compromised. Follow-up laser surgery is frequently needed to remove a secondary membrane that can form. Topical antiinfective drugs and mydriatic-cycloplegics are used preoperatively, and corticosteroids, antibiotics, and mydriatics are used postoperatively. Corrective lenses may be used to correct vision, and strong lighting may be used to enhance vision until surgery is performed.
nursing considerations Before surgery, nursing care is focused on assessment and attention to self-care deficits related to decreasing vision. Preoperative care includes education about the surgical experience and lens implants and reduction of anxiety about impending surgery. Postoperative education focuses on proper use and instillation of eyedrops, prevention of infection, and activity restrictions.


Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.
cataract [kat´ah-rakt]
opacity of the lens of the eye or its capsule. adj., adj catarac´tous.Causes and Symptoms. Some cataracts result from injuries to the eye, exposure to great heat or radiation, or inherited factors. The great majority, however, are “senile” cataracts, which are apparently a part of the aging process of the human body.

Blurred and dimmed vision are often the first symptoms. The patient may find that a brighter reading light is needed, or objects must be held closer to the eyes for better vision. Continued clouding of the lens may cause double vision; eventually there may be a need for frequent changes of eyeglasses. These symptoms do not necessarily indicate cataract, but if any of them are present, an ophthalmologist should be consulted immediately.
Treatment. The only known effective treatment for cataract is surgical removal of the lens (lens extraction or cataract extraction). The procedure of choice was formerly intracapsular extraction, with total removal of the lens within its capsule. This may be done by forceps or by cryoextraction using a supercooled metal probe that forms a bond with the lens capsule. The inner portion of the lens can be removed by emulsification and aspiration. More recently the removed cataract has been replaced with a plastic intraocular lens. In this procedure the inner portions of the lens (the nucleus and cortex) may be all that is removed; the capsule is retained and the intraocular lens is placed inside it.

The lens of the eye serves only to focus light rays upon the retina. After cataract extraction the loss of the natural lens is compensated for by either special eyeglasses or contact lenses. Implantation of a permanent artificial lens, either during cataract surgery or later, is an alternative to use of cataract spectacles and a removable contact lens.
Patient Care. Eye drops are administered to produce mydriasis and vasoconstriction. Because these patients may have extremely poor eyesight, care should be taken that they do not injure themselves. (See also vision.) Local anesthesia is usually preferred for the surgical procedure and preoperative medications are given to produce drowsiness. Ambulatory care surgery with same-day admission and discharge is becoming increasingly routine. Careful observation of the patient on follow-up visits is important. One needs to be on the alert for a complaint of pain in the eye followed by nausea and vomiting. These could be signs that the patient has increased intraocular pressure within the operative eye and measures need to be taken to reduce the pressure.

after-cataract any membrane of the pupillary area after extraction or absorption of the lens. See also secondary cataract.
atopic cataract cataract occurring, most often in the second to third decade, in those with longstanding atopic dermatitis.
brown cataract (brunescent cataract) senile cataract appearing as a brown opacity.
capsular cataract one consisting of an opacity of the capsule of the lens.
complicated cataract secondary cataract.
cortical cataract an opacity in the cortex of the lens.
hypermature cataract one in which the entire lens capsule is wrinkled and the contents have become solid and shrunken, or soft and liquid.
immature cataract (incipient cataract) an incomplete cataract; the lens is only slightly opaque and the cortex clear.
intumescent cataract a mature cataract that progresses; the lens becomes swollen from the osmotic effect of degenerated lens protein, and this may lead to secondary angle closure (acute) glaucoma.
lenticular cataract opacity of the lens not affecting the capsule.
mature cataract a cataract that produces swelling and opacity of the entire lens; cataracts are removed before maturity.
presenile cataract a subcapsular senile cataract in a person under 40 years of age.
secondary cataract a cataract, usually posterior subcapsular, that arises from either disease (especially iridocyclitis), degeneration (such as chronic glaucoma or retinal detachment), or surgery (such as glaucoma filtering or retinal reattachment).
senile cataract cataract with no obvious cause occurring in persons over 50 years old.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
cataract,
n degenerative eye disease marked by the loss of transparency of the lens, resulting in an opaque, milky appearance behind the pupil.Cataract definitions 500069-fx12.jpgCataract definitions enlarge.gifCataract.



Jonas: Mosby's Dictionary of Complementary and Alternative Medicine. (c) 2005, Elsevier.
cataract (kat´Cataract definitions 500051-fx1.gifrakt),
n an abnormal progressive condition of the lens of the eye, characterized by loss of transparency.
Mosby's Dental Dictionary, 2nd edition. © 2008 Elsevier, Inc. All rights reserved.
cataract
opacity of the lens of the eye or its capsule or both. Cataract may result from injuries to the eye, exposure to great heat or radiation, or inherited factors. Rare in cattle and swine, common in dogs. Treatment consists of surgical removal of the lens (lens extraction or cataract extraction). May affect the entire lens or be localized, e.g. posterior polar cataract.
acquired cataractany non-congenital cataract; usually the result of trauma, systemic disease or another eye disorder.

after-cataract 1. any membrane of the pupillary area after extraction or absorption of the lens.
2. secondary cataract (below).

capsular cataract one consisting of an opacity of the capsule of the lens.

complicated cataract a cataract occurring secondarily to other intraocular disease.

congenital cataract present at birth; often not progressive. See also white eye calf syndrome.

cortical cataract an opacity in the cortex of the lens. The common form of cataract in dogs; inherited in many breeds, often in association with progressive retinal atrophy.

developmental cataract one that occurs at any age before the animal becomes an adult.

diabetic cataract one associated with diabetes mellitus.

electric cataract one caused by electrical current as in electrocution.

embryonal cataract one caused by prenatal influences.

focal ring cataract a perinuclear opacity with normal lens fibers surrounding it. Usually the result of an in utero or neonatal insult to the lens.

galactosemic cataract see galactosemia.

hyaloid cataract a focal opacity at the point where the hyaloid artery meets the posterior lens capsule. See also mittendorf's dot.

hypermature cataract one in which the lens has begun to liquefy.

immature cataract incomplete opacity.

incipient cataract a very early stage of development with no impairment of vision.

inherited cataract occurs in a number of breeds of cattle, often in combination with other abnormalities of the eye. Affected calves are usually normal in other respects and can be reared if the inconvenience of their blindness can be overcome. Also occurs in dogs, often with late onset and in association with other inherited ocular defects such as progressive retinal atrophy.

intumescent cataract a mature cataract that has become swollen.

juvenile cataract one developing in very young animals, for example dogs less than 6 months of age.

lenticular cataract opacity of the lens not affecting the capsule.

mature cataract one in which the lens is completely opaque.

morgagnian cataract liquefaction, except the nucleus which drops to the bottom of the lens, and shrinkage of the capsule.

nuclear cataract one involving the nucleus of the lens; the common form of congenital cataracts.

nuclear Y cataract a form of congenital cataract in which small opacities outline the Y suture of the nucleus.

nutritional cataract see galactosemia.

radiation cataract one caused by radiation, as in radiotherapy.

reduplication cataract a capsular opacity covered by another layer of epithelium.

secondary cataract 1. one that forms after most of the lens has been removed.
2. complicated cataract.

senile cataract occurs in the aged of all species, preceded by nuclear sclerosis.

subcapsular cataract may be anterior or posterior. Inherited in several breeds of dogs.

toxic cataract one caused by exposure to a toxic substance.

traumatic cataract one caused by trauma.

Saunders Comprehensive Veterinary Dictionary, 3 ed. © 2007 Elsevier, Inc. All rights reserved
cataract
Partial or complete loss of transparency of the crystalline lens substance or its capsule. Cataract may occur as a result of age, trauma, systemic diseases (e.g. diabetes), ocular diseases (e.g. anterior uveitis), high myopia, long-term steroid therapy, excessive exposure to infrared and ultraviolet light, heredity, maternal infections, Down's syndrome, etc. The incidence of cataract increases with age, amounting to more than 50% in the population over 82 years. It is also more prevalent in Africa, Asia and South America than in Europe and North America. The main symptom is a gradual loss of vision, often described as 'misty'. Some patients may also notice transient monocular diplopia, others fixed spots (not floaters) in the visual field and others better vision in dim illumination. Cataracts can easily be seen with the retinoscope, the ophthalmoscope and especially with the slit-lamp, although depending on the type, one instrument may be better than the other. At present the main treatment is surgical. Extraction is performed for one of three reasons: visual improvement, medical or cosmetic.See after-cataract; juvenile idiopathic arthritis; biometry of the eye; crystalline lens capsule; Wilson's disease; blue field entoptoscope; glare tester; hyperacuity; crystalline lens; intraocular lens; leukocoria; clinical maxwellian view system; lenticular myopia; phacoemulsification; Down's syndrome; persistent hyperplastic primary vitreous.
age-related cataract Cataract affecting older persons. It is the most common type of cataract and may take several forms: cortical, cuneiform, nuclear, mature or subcapsular. Syn. senile cataract.
anterior capsular cataract A small central opacity located on the anterior lens capsule, either of congenital origin or due to a perforating ulcer of the cornea. See Vogt's sign.
axial cataract An opacity situated along the anteroposterior axis of the crystalline lens (Fig. C3).
bipolar cataract An opacity involving both the anterior and the posterior poles of the lens (Fig. C3). See polar cataract.
blue cataract See blue-dot cataract.
blue-dot cataract A developmental anomaly of the crystalline lens characterized by numerous small opacities in the outer nucleus and cortex, which appear as translucent bluish dots. The condition is very common and does not usually affect acuity. Syn. blue cataract; diffuse cataract; punctate cataract.
brown; brunescent cataract See nuclear cataract.
capsular cataract An opacity confined only to the capsule of the crystalline lens, anteriorly or posteriorly. It is usually congenital, although it may be acquired as a result of trauma or inflammation.
central cataract See nuclear cataract.
chalky cataract A cataract characterized by the presence of lime salt deposits.
Christmas tree cataract A rare type of diffuse age-related cataract in which the opacities appear as highly reflective crystals.
complicated cataract A cataract caused by or accompanying another intraocular disease, such as glaucoma, cyclitis, anterior uveitis or a hereditary retinal disorder such as retinitis pigmentosa or Leber's disease. Syn. secondary cataract. See cuneiform cataract; Leber's hereditary optic atrophy; retinitis pigmentosa; Down's syndrome; Fuchs' syndrome; rubella syndrome.
congenital cataract Cataract occurring as a result of faults in the early development of the lens. Some may be hereditary, usually autosomal dominant. The cause of others may be chromosomal abnormalities (e.g. Down's syndrome, Turner's syndrome), carbohydrate metabolic disorders (galactosaemia, galactokinase deficiency), rubella syndrome, etc. The condition requires urgent treatment to prevent the development of amblyopia. See capsular cataract; lamellar cataract; nuclear cataract; polar cataract; sutural cataract.
coronary cataract A cataract characterized by a series of opacities having the shape of a crown or ring near the periphery of the lens
cortical cataract Cataract affecting the cortex of the lens. The opacities often begin as spokes or isolated dots or clusters forming the cuneiform or subcapsular types of cataract, but eventually the opacity spreads through the entire cortex.
cuneiform cataract Age-related cataract characterized by opacities distributed within the periphery of the cortex of the lens in a radial manner, like spokes on a wheel See subcapsular cataract.
cupuliform cataract See sub-capsular cataract.
diabetic cataract Cataract associated with diabetes. In old eyes this type is similar to that of a non-diabetic person but in young eyes it is typically of the snowflake type.
diffuse cataract See blue-dot cataract; Christmas tree cataract.
electric cataract An opacity caused by an electric shock.
cataract extraction, extracapsular (ECCE) Surgical procedure for the removal of a cataractous crystalline lens. The anterior capsule is excised, the lens nucleus is removed and the residual equatorial cortex is aspirated. The posterior capsule may be polished. An intraocular lens implant may then be inserted. See after-cataract; biometry of the eye; capsulectomy; intraocular lens; Elschnig's pearls;phacoemulsification; Soemmering's ring.
cataract extraction, intracapsular (ICCE) Surgical procedure for the removal of a cataractous crystalline lens. The entire lens, together with its capsule, is removed. This procedure is rarely performed nowadays. See ligament of Wieger.
fluid cataract Hypermature cataract in which the lens substance has degenerated into milky fluid.
glassblower's cataract See heat-ray cataract.
heat-ray cataract Cataract due to excessive exposure to heat and infrared radiation. Syn. glassblower's cataract; thermal cataract.See exfoliation of the lens; infrared.
hypermature cataract The last stage in the development of age-related cataract in which the lens substance has disintegrated.See incipient cataract; intumescent cortical cataract; mature cataract; phacolytic glaucoma.
incipient cataract The first stage in the development of age-related cataract characterized by streaks similar to the spokes of a wheel or with an increased density of the nucleus. See intumescent cortical cataract; mature cataract; crystalline lens; second sight.
intumescent cortical cataract A stage of development of a cataract in which the lens, especially the cortex, absorbs fluid and swells. It may lead to secondary angle-closure glaucoma. The cataract can progress to the hypermature stage in which case the fluid leaks out, resulting in shrinkage of the lens and wrinkling of the anterior capsule, leaving the harder nucleus free within the capsule. See morgagnian cataract.
lamellar cataract A congenital cataract affecting one layer of the crystalline lens only. Syn. zonular cataract.
mature cataract The middle stage in the development of age-related cataract characterized by a completely opaque lens and considerable loss of vision. See hypermature cataract; incipient cataract.
morgagnian cataract A hypermature age-related cataract in which the cortex has shrunk and liquefied and the nucleus floats within the lens capsule. Degraded lens proteins may leak into the aqueous humour and cause phacolytic glaucoma. Syn. cystic cataract; sedimentary cataract. See intumescent cortical cataract.
nuclear cataract An opacity affecting the lens nucleus. It can be either congenital or age-related in origin. It frequently leads to an increase in myopia (or decrease in hyperopia). In some cases it reaches such a brown colour that it is called brunescent cataract (or brown cataract). Syn. central cataract (Fig. C3).
polar cataract A congenital opacity found at either pole of the crystalline lens. Anterior polar cataract may be flat or project as a conical opacity (pyramidal cataract) into the anterior chamber (Fig. C3). Posterior types may be associated with persistent hyaloid remnant (Mittendorf's dot).
punctate cataract See blue-dot cataract.
pyramidal cataract See polar cataract.
senile cataract See age-related cataract.
secondary cataract 1. Syn. for complicated cataract. 2. Syn. for after-cataract.
snowflake cataract A cataract characterized by greyish or whitish flakelike opacities. It is usually found in young diabetics or severe cases of diabetes (Fig. C3).
soft cataract Cataract in which the lens nucleus is soft. See crystalline lens.
subcapsular cataract An age-related opacity located beneath the anterior or posterior capsule. It may spread from the periphery of the cortex like spokes on a wheel (cuneiform cataract). This is the most common type of cortical cataract. The opacities may also be confined to the posterior layers of the cortex with a granular or lace-like appearance (cupuliform cataract). Subcapsular cataracts are often the result of radiation exposure, age, toxic damage (e.g. from corticosteroids), or secondary to eye diseases (e.g. uveitis, retinitis pigmentosa). (Fig. C3).
sunflower cataract See chalcosis lentis.
cataract surgery See capsulectomy; capsulorhexis; capsulotomy; extracapsular cataract extraction; intracapsular cataract extraction;phacoemulsification.
sutural cataract A congenital cataract in which the opacities are found along the anterior and/or posterior lens sutures. The opacities may appear Y-shaped or flower-shaped. The condition is often associated with Fabry's disease.
thermal cataract See heat-ray cataract.
traumatic cataract Cataract following injury to the lens, its capsule, or to the eyeball itself. It is commonly unilateral. Penetrating trauma of the lens causes rapid opacification of the cortex or even most of the lens contents. Concussion of the lens may result in capsular, subcapsular or cortical opacities. See Vossius' ring.
zonular cataract See lamellar cataract
.Cataract definitions F0C-03-S2958.jpgCataract definitions enlarge.gifFig. C3
Examples of cataracts (A, bipolar; B, pyramidal; C, axial; D, subcapsular (cupuliform); E, nuclear; F, coronary; G, snowflake; H, cuneiform)



Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
cataract
Lens opacity Ophthalmology Partial or complete opacification of the ocular lens or capsule, which impairs vision or causes blindness Classification Morphology–size, shape, location; etiology–eg DM, corticosteroids, trauma, und so weiter; time of occurrence–eg in elderly Clinical Double or blurred vision; ↑ sensitivity to light, glare Diagnosis Slit lamp microscopy Treatment Phacoemulsion, surgery. See Black cataract, Congenital cataract, Snowflake cataract, Sunflower cataract.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
Patient discussion about cataract.
Q. What Is a Cataract? My father has cataract in his eye, which interferes a lot with his vision. What is cataract?
A. A senile cataract (or clouding of the eye), occurring in the aged, is characterized by an initial opacity in the lens, subsequent swelling of the lens and final shrinkage with complete loss of transparency. This condition as an effect on ones vision, and it is important to treat it early, as it becomes harder to treat as time goes by, and may eventually lead to blindness in that eye.

Q. What vitamin through diet shall I take to prevent cataract and how can I help my dad? My father recently had a cataract surgery. This was his second cataract surgery. After this surgery I got scared as what’s going wrong with my dad and he had the cataract the second time. As per the doctor, my dad must be short in vitamins in his diet. He has been given some vitamin tablets. I know that cataract is genetic. I guess I may also have cataract in my old age. What vitamin through diet shall I take to prevent cataract and how can I help my dad?
A. Sorry to disagree, but to date there is no well-controlled study that proves the benefit of vitamin supplementation with respect to prevention of cataracts. There are numerous studies that "suggest" a correlation between use of vitamins and development of cataracts, but none that would lead one to believe in a causal relationship.

That being said, I generally recommend an antioxidant multivitamin to my patients as it is unlikely to cause any harm and there may actually be a benefit (we just cannot state with confidence that there is, in fact, a benefit).

Sincerely,

David D. Richardson, M.D.
Medical Director





Q. I had cataract surgery with iol implant, and ever since I have awful light sensitivity. Any ideas? I can't go into a "super store" without my sunglasses. My eyes ache at the end of the day. My doctor says "I don't know!"
A. May sound a bit silly question, but have you tried to consult your ophthalmologist (eye doctor, e.g. the one that performed the operation) about it? Cataract surgery, although considered very successful, isn't problem-free. Primary physician may not have the necessary specialization to deal with these subjects.