From Cataracts to Normal Vision

By: Dr. Don Miller

Cataracts, loss of vision due to clouding of the eye lens, are often considered to be a problem for advancing age. Actually the problem and corrective surgery can affect people of any age. There are several options to restore focus after removal of the natural lens.

Clouding of the cornea can cause similar symptoms. The treatment is much newer than for cataracts, as it involves transplants of corneal tissue, usually taken from a deceased donor.

Many centuries before the existence of photo sensitive plates and films, the "pin hole lens" was used to make tracings of subjects. "Camera obscura" which is Latin for "veiled chamber", led to the name for photographic cameras. The smaller the hole, the better the focus, but at the cost of reduced light. Lenses eventually permitted focusing with larger sized holes and more light.

Anyone who has had eyes dilated by an eye doctor has experienced that dramatic loss of focus when the pupils are anything but pin hole lenses. Complete removal of the natural lens in cataract surgery makes focus impossible for most patients.

Before our time, the only restoration of focus after cataracts was by means of spectacles with very thick lenses. Range of focus was limited, and comfort was poor. Development of plastic lenses helped only partly.

Contact lenses provided a nearly natural solution, but still over restricted ranges. However, light weight spectacles can be worn over those contacts with smaller range of focus.

A modern alternative is the intraocular lens (IOL), which is like a miniature contact lens placed inside the eye. First examples were made of materials also used for rigid contact lenses, but soft materials are now an option. Work has been done on multi focal / adaptive IOLs, but there is far less working room inside the eye than in spectacles.

Whether the corrective lens is inside the eye or on the cornea, the result for most cataract patients is good focus at limited range of distances. However variable focus spectacles can be used to complete the range of focus.

Now consider other factors. The base line is those heavy eyeglasses which were uncomfortable for patients of any age, but especially troublesome for children and youth.

The IOL, like contact lenses, can be changed when the focus changes, as is normal for aging. If the implanted IOL is part of the treatment, much adjustment over time can be achieved with contact lenses or spectacles.
The IOL is essentially no care after installation.

Contact lenses can be very difficult to clean and install for very young, very old, or physically impaired people of intermediate ages. Fortunately various extended wear contacts are now available. Because neovascularization is a real concern with long wear of contacts, even with the more permeable new materials, it is practical for care givers to get at least a day's wear, if not more than 24 hours, for their care receivers.

Are cataracts or clouded corneas of little significance? Certainly not. But the modern treatment options permit almost complete restoration of what most of us would call normal vision. In fact, cataract surgery is now the most frequent form of surgery in the United States, with several million cases in a year.

Isn't science grand?

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For more articles about safe and enjoyable use of contact lenses and spectacles, see by Dr. Don Miller.

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