What is a Cataract?
A cataract is a clouding of the natural lens inside your eye. This lens, located behind the iris, works like the lens of a camera – focusing light images on the retina, which sends images to the brain. The human lens can become so clouded it keeps light and images from reaching the retina.
A cataract can be the reason sharp images become blurred, bright colors become dull, or seeing at night is more difficult. It may also be why the reading glasses or bifocals that used to help you read or do other simple tasks no longer seem to help. Vision with cataracts has been described as seeing life through old, cloudy film.
A cataract is not a “film” over the eyes, and neither diet nor lasers will make it go away, nor can it be prevented. Eye injury, certain diseases, or even some medications can cause the clouding. But developing a cataract can also be a part of the natural aging process. The best way to treat a cataract is with surgery that removes the old, clouded lens and replaces it with a new, artificial one to restore your vision, and, in many ways, significantly improve your quality of life.
What is Presbyopia?
Presbyopia is the condition in which the lens of the eye loses its ability to focus. It is a common condition that could accompany cataracts and impair your ability to see objects that are close up. Have you ever found yourself holding a menu or a book farther and farther away to read it? The need for reading glasses is usually a sign of presbyopia. This aging of the eyes eventually affects everyone. If you have cataracts with presbyopia, a multifocal lens can correct both conditions.
What is an IOL?
An intraocular lens (IOL) is the replacement lens that is surgically implanted in the eye to replace the existing clouded lens during cataract surgery. The good news is that you’ve encountered cataracts at a time when intraocular lens technology has taken great leaps of progress. Traditionally, the replacement lens used for cataract surgery was a monofocal IOL. This type of lens restored good functional distance vision, but people still needed to continue wearing reading glasses. Today you also have the option of an IOL lens, which can improve vision in a full range of distances, from near to far.
When the surface of a normal eye’s cornea has a spherical curve, like the shape of a basketball, light rays passing through it bend toward its center and focus on one spot. When the surface of the cornea is cured more like a football, with both flatter and steeper curves vision becomes distorted and is called corneal astigmatism. The light rays are not focused at one spot to provide clear vision. A person who has both cataract and corneal astigmatism will not regain high-quality distance vision after surgery by removing the cataract unless the astigmatism is also corrected.
If you have astigmatism you may still experience blurred and distorted vision because a standard IOL cannot correct corneal astigmatism. A toric IOL provides significantly improved distance vision and may reduce the need for corrective lenses.