Cataracts are an opacity in the crystalline lens inside the eye. In advance stages the cataract can become so opaque as to appear white through the pupil. Such advanced cataracts appeared to the Greeks as white tumultuous water, hence the term cataract.
The degree of opacity directly affects visual clarity. Also affected is color fidelity; typically cataracts become yellow to brownish yellow. Not until after the cataract is removed does the person realize how distorted the color perception was, not to mention the improved clarity. Typically, cataracts take a few years to develop, but some types require only a few weeks or months. The most common causes of cataracts are aging, family history, UV-light, medications, and trauma.
Cataract surgery is the procedure used to remove a cataract. Since the lens normally hels to focus the light (about 1/3 of the focusing is done by the lens, the remaining 2/3 is carried out by the cornea), once it is removed vision is quite blurred. Not too many years ago, before lens implants, patients wer required to wear thick, Coke bottle-like glasses. The distortion from these aphakic (without lenses) spectacles is tremendous. Once lens implants, also known as intraocular lenses, were perfected, cataract surgery become one of the most successful surgeries done on humans.
Lens implants are 5 to 6 mm in diameter. The materials used vary from rigid to foldable plastics; the type selected is best determined on an individual bases. Optically, most are fixed fro a given focal point, but some designs incorporate multifocal properties, allowing one to see at both near and far. But as with most things in life, multifocal designs are a compromise: what one gets in convenience, one loses in clarity (contrast).
The cataract surgery itself takes very little time:10 to 15 minutes in the hands of an experienced surgeon. Often that same day, usually within a few minutes or hours, the patient can begin using their eye. The complete healing requires several days after which times glasses may be required depending upon the patient’s optical condition (for example, residual astigmatism may be present).
A common question is why won’t new glasses help? Currently, there is no other solution for cataracts: the cataract must be removed and replaced with a clear lens. Initially, as the cataract is starting, new glasses can help, but as the cataract progresses and becomes more opaque, new glasses do nothing to improve clarity. (this situation is like wondering why a clear window next to a frosted glass window won’t make the frosted glass window less cloudy.) Frequently, the fellow eye requires cataract surgery within 2 years after the surgery in the first eye. Should both eyes need cataract surgery, it is usually best to wait 2 to 4 weeks between eyes.
The cataract surgery is done with local or topical anesthesia (occasionally general anesthesia is required). Surgical techniques very, but most ophthalmologists use a technique known as phacoemulsification, a method pioneered by Drs. Charles Kelman and Richard Kratz. Lasers are used experimentally, but are not commonly used to remove cataracts; they are also not very efficient for this task.
