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Cataracts

 

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What are Cataracts?

A cataract is a clouding of the eye's natural lens, which lies behind the iris and the pupil. The lens works much like a camera lens, focusing light onto the retina at the back of the eye. The lens also adjusts the eye's focus, letting us see things clearly both up close and far away.

 

The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and allows light to pass through it.

 

As we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract, and over time, it may grow larger and cloud more of the lens, making it harder to see.

 

Researchers are gaining additional insights about what causes these specific types of proteins (crystallins) to cluster in abnormal ways to cause lens cloudiness and cataracts. Recent findings suggest that fragmented versions of these proteins bind with normal proteins, disrupting normal function.

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Cataracts are classified as one of three types:
A subcapsular cataract begins at the back of the lens. People with diabetes, high farsightedness, retinitis pigmentosa or those taking high doses of steroids may develop a subcapsular cataract.

 

A nuclear cataract is most commonly seen as it forms. This cataract forms in the nucleus, the center of the lens, and is due to natural aging changes.

 

A cortical cataract, which forms in the lens cortex, gradually extends its spokes from the outside of the lens to the center. Many diabetics develop cortical cataracts.

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Intraocular Lenses (IOLs)

 

The new multifocal and accommodating IOLs offer the possibility of seeing well at more than one distance, without glasses or contacts. Here are a few examples (note: this is not a complete list):

Presbyopia, is the breakdown of the ciliary muscle (which allows focusing from near to far). The ciliary muscle contracts in its effort to move the lens forward, bending it slightly for closeup focusing; but the lens resists because it is not as flexible as it was when the eye was younger.

AcrySof ReStor. This lens uses apodized diffractive technology -- a design that responds to how wide or small the eye's pupil might be -- to provide near, intermediate and distance vision. Aspheric lenses, because they are somewhat flat near the edges, are thought to improve contrast sensitivity and provide better night vision than other types of multifocal IOLs.

Clinical studies show 80 percent of people who received the lens didn't use glasses for any activities after their cataract surgery. Eighty-four percent who received the lens in both eyes had distance vision of 20/25 or better, with near vision of 20/30 or better.

AcrySof Toric Intraocular Lens. This lens is an advanced technology that now makes it possible to correct the cataracts clouding your vision -- and the corneal astigmatism distorting your vision -- at the same time.

The technology behind the AcrySof Toric IOL offers precise astigmatic correction that reduces or eliminates corneal astigmatism and delivers significantly improved distance-vision without glasses or contacts for cataract patients with pre-existing astigmatism.