A cataract is a clouding of the eye's lens, which causes interference with sight. The majority of catacacts are caused by aging, which triggers chemical changes in the eye's natural lens. The age at which this occurs varies greatly, with some people being affected in their fifties, some in their late eighties. Cataracts can also be caused by metabolic changes, injury, radiation or toxic chemicals.

The word "Cataract" comes for the Greek for waterfall. Until the mid 1700s cataracts were believed to be caused by the flow of opaque materials into the eye.

A clouding of the cornea, most common in older people, but not unheard of in people under the age of fifty. It is usually caused by a buildup of proteins in the cornea that occurs in aging, but trauma to the cornea (such as a blunt hit by a ball) can cause cataracts in younger patients

The surgery most often used to remove a cataract is phacoemulsification, a type of microsurgery in which an incision is made and a device is used to suction the inside of the cataract. Recently topical anesthesia (using lidocaine gel) in addition to a benzodiazepene (like Valium or Versed) has been used to numb the eye, although sometimes a block (more potent anesthesia using a syringe) is required. After the surgery, an intraocular lens implant(IOL)is sutured (stitched with a microscopically fine thread) over the the eye, and the benign shell of the caract is left to speed recovery.

In some cases, after a phacoemulsification surgery, residual proteins from the cataract will build up and a follow-up surgery will be required. Most frequently, no scalpel is required the second time, and the buildup can be adequately eliminated with a low-intensity YAG laser.

It is interesting to see the effect Cataract had on the work of the great French Impressionist, Claude Monet.

From 1912 Monet began to develop Cataract in his left eye. As the cataract evolved and his sight deteriorated, it began affecting his work as well.

The effects of the Cataract are clearly seen in his work from the time. Monet painted many paintings of his garden in Giverny, a small town in France. The left hand side of the Giverny paintings, dated after 1912, is characterized with shades of blue, a common effect of the Cataract. While the right hand side of those paintings (i.e the healthy eye) remain loyal the true colours of the garden.

In 1923 Monet had a surgery to remove the Cataract from his left eye. The sudden change in his paintings is amazing. Both sides of the paintings match the colours of the garden.
When Monet noticed the difference between his post-surgery paintings and his pre-surgery paintings, he destroyed many of the latter in rage.

A congenital cataract is opacification of the lens that occurs in the fetus at some time during pregnancy.

Although there are many diseases and inherited disorders that can lead to congenital cataracts, the actual incidence of congenital cataracts is low. Sometimes these things just happen. The odds of it happening are slim, and the odds are extremely slim that two siblings will develop cataracts, especially congenitally.

This is a partial list of possible causes of congenital cataracts:
galactosemia (the inability to break down galactose sugar)
Lowe syndrome
congenital rubella syndrome
Sieman's syndrome
Down syndrome
Pierre-Robin syndrome
hereditary congenital cataracts
Hallerman-Streiff syndrome
cerebrohepatorenal syndrome
Trisomy 13
Conradi syndrome
Ectodermal dysplasia
Marinesco-Sjogren syndrome
Note: Sometimes, no cause can be identified.
In many of these causes, cataracts are only one of the complications of the disease.

Symptoms are opacity of the lens, often evident at birth without special viewing equipment and appearing as a whitish discoloration in an otherwise normally dark pupil

Signs And Tests:
slit lamp examination by an ophthalmologist
standard eye exam
ultrasonography of the eye

The treatment involves surgical cataract removal followed by placement of an intraocular lens (IOL).

-Adapted from information taken from WebMD

Cataract is the loss of transparency of the crystalline lens in the eye. This is most commonly due to ageing but there are other causes including congenital conditions, disease, and trauma. Certain drugs are also implicated in cataract development.

There is a misconception that a cataract can be seen as a "film" growing over the front of the eye. This film is probably not cataract but a pterygium or some opacification involving the cornea. Cataract cannot usually be seen on casual inspection because it is happening in the lens which is just behind the iris and the pupil aperture.

Some noders may have had cataract surgery. It is an extremely successful surgical procedure in which the crystalline lens, which has become cloudy or opaque, is extracted.

This removes almost all the focussing ability of the eye. Up until the 1970's, these patients would then have to be fitted with an enormously thick pair of glasses or (assuming they could tolerate it), a powerful rigid contact lens. Nowadays the extracted lens is replaced by an implanted artificial lens of a similar effectivity.

In our larger cities, it is likely that 60 or more people are having cataract extractions with lens implants on any given weekday.

It all happens something like this. First your opaque lens needs to be removed. In the operating theatre and using local anaesthetic, the ophthalmologist makes a tiny incision at the edge of the cornea to gain access to the cloudy lens through a dilated pupil. With a thin hollow titanium needle attached to a hand-piece containing a piezo-electric crystal which vibrates longitudinally at ultrasonic frequencies, the contents of the cloudy lens are emulsified. An irrigation and aspiration system sucks out the emulsified contents through tiny tubes and your "cataract" ends up in the waste pipe. This process is called phaco-emulsification.

For the moment then, you have no lens.

In the meantime an artificial replacement lens of a certain dioptral strength has been selected and is waiting on the surgical tray. The power of this lens is based on pre-operative measurements including ultrasound scan information. The surgeon delivers this lens by "injecting" it through another hollow needle into the now vacant space left by the recently removed cataractous material. Here it "deploys" by unrolling and will require a bit of skillful nudging into place by the surgeon. The implanted lens has cleverly designed stabilizing attachments which protrude from the edge to keep it in position, just behind the pupil.

In a few more steps, the operation is concluded. Most times, the incision is so small that no sutures are required. Post operative eye drops and follow-up appointments are arranged and the patient may go home about 6 hours after arriving at the hospital. Often the patients are already commenting on their improved eyesight as they are being driven home.

Because the artificial lens is of a fixed shape and not flexible, eyeglasses are often necessary after the operation to provide clear reading vision. To minimise the dependancy on glasses, the surgeon may select intra-ocular lens (IOL) strengths so that one eye is biased for close work and the other for distance vision.

The capsule of the patient's natural lens is left in place behind the implanted lens which increases the success and safety of this operation. Some months or years later, this remaining lens capsule may become opaque, causing a drop in vision. This is addressed by using a YAG laser to form a hole in the now opaque lens capsule which can now be done with relative safety. This is a short procedure, often done in the surgeon's office and once again the result is quite gratifying.

Cataract surgery is often rated as the most successful and effective type of surgery ever. It is a far cry from the days when the surgeon had to peel back most of your cornea to surgically remove your cataract. Old timers will remember family members having to stay in bed with their head "sandbagged" for days on end to prevent movement after the operation. Then came the even more challenging process of getting fitted with a contact lens or glasses which looked like magnifiers.

It is medical technology at its most elegant.

Whilst the average age for cataract surgery is during the eighth decade, the eye-care practitioner may see the first signs of your age-related cataract when you are fifty five. Only through repeat visits can the progress be assessed and it may be another decade before you need to be referred for surgery. Some patients never progress to a point where surgery is required.

Cat"a*ract (?), n. [L. cataracta, catarracles, a waterfall, Gr. , , fr. to break down; in the passive, to fall or rush down (of tumors) to burst; down + to break.]

1.

A great fall of water over a precipice; a large waterfall.

2. Surg.

An opacity of the crystalline lens, or of its capsule, which prevents the passage of the rays of light and impairs or destroys the sight.

3. Mach.

A kind of hydraulic brake for regulating the action of pumping engines and other machines; -- sometimes called dashpot.

 

© Webster 1913.

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