Cataracts

What is a cataract?

A cataract is the opacification of the natural lens. The lens is the portion of the eye immediately behind the iris. It acts like the lens of a camera focusing on an image.

Opacification may take a number of forms, but the common endpoint is the lack of a sharply focused image on the retina. Using the camera analogy, it is equivalent to having a dirty or distorted lens.

What causes cataracts?

Cataracts increase exponentially with age. They are common in those over 60 but do not always require removal. Other associations include ultraviolet light, diabetes mellitus, trauma to the eye, severe electrical shock, strong family history and steroid use.

What are the symptoms of cataracts?

Impairment of visual function usually occurs over years or decade but may proceed more rapidly. Painless loss of visual clarity. Glare and difficult night driving can be common symptoms.

How are cataracts treated?

Surgical removal with the placement of an intraocular lens is the best alternative when glasses no longer provide the quality of vision desired. Intraocular lenses are usually placed within the bag that formerly held the natural lens or cataract. The lenses are made of PMMA, acrylic or silicone. The natural lens is usually removed by first breaking it up into very small pieces by an ultrasonic technique called phacoemulsification. The remnants are then suctioned from the eye. The new lense is inserted into the eye to take the place of the cloudy lens that was removed.

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When should I consider having my cataracts removed?

I like to use the analogy of cataracts being like a dirty window. Everyone has a different threshold for when the window is dirty enough that it requires washing. Similarly when you feel that performance of daily activities and functions is being impaired by visual inadequacy and no other cause can be found it is probably time to consider the removal of the cataract(s). A cataract in only one eye does not bother many individuals. If this is the case there is usually no need for surgery. Other people are annoyed with the lack of clarity in one eye or have trouble with the corresponding reduction in depth perception.

It is rare that cataracts require removal for any reason other than reduced clarity. An exception is when there is a need for improved visualization of the retina to follow or treat a disease process. Other obscure reasons include a degenerating lens capsule that produces inflammation or a swollen lens, which causes glaucoma. Medicare requires 20/40 vision or worse criteria for surgery but certain complementary tests, such as glare testing, is often helpful in assessing visual disability as well.

Improvement of vision is seen after 90-95% of cataract surgeries, but complications do occur and visual loss is possible. For this reason, it is imperative that the individual feels visual disability is sufficient for them to warrant the small risk of visual loss.