Cataracts Information

Cataract

Your eye works a lot like a camera. Light rays focus through your lens onto the retina , a layer of light-sensitive cells at the back of the eye. 

Over time, the lens of our eye can become cloudy, preventing light rays from passing clearly through it onto the retina. The loss of transparency may be so mild that vision is barely affected, or it can be so severe that no shapes or movements are seen-only light and dark. When the lens becomes cloudy enough to obstruct vision to any significant degree, it is called a cataract. Eyeglasses or contact lenses can usually correct slight changes in vision caused by early cataracts, but they cannot sharpen your vision if a more severe cataract is present.

The most common cause of cataract is aging. Other causes include trauma, medications such as prednisone or other steroids, systemic diseases such as diabetes, and prolonged exposure to ultraviolet light. Occasionally, babies are born with a cataract.

Cataracts typically develop slowly and progressively, causing a gradual and painless decrease in vision. Other changes you might experience include: glare, particularly at night or from bright sunlight; frequent changes in your eyeglass prescription; a decrease in color intensity; a yellowing of images; and less commonly, double vision.

As the eye's natural lens gets harder, farsighted (presbyopic) people, who have difficulty focusing up close, can experience improved near vision and become less dependent on reading glasses. However, nearsighted (myopic) people become more nearsighted, causing a worsening in their distance vision. Some kinds of cataract affect distance vision more than reading vision. Others affect reading vision more than distance vision.

With a routine, outpatient surgical procedure, an eye surgeon can remove the cataract.  A synthetic intraocular lens (IOL) is almost always inserted at the time of cataract extraction to replace the focusing power of the natural lens. IOLs can be monofocal (fixed-focus for a preset distance) or multifocal, which allows focused vision at many distances. The time to have cataract surgery is when the cataract is affecting your vision enough to interfere with your normal lifestyle.

Cataract surgery is a very successful operation. One and a half million people have this procedure every year in the United States. As with any surgical procedure, complications can occur during or after surgery, and some are severe enough to limit vision.  In the vast majority of cases, however, vision, as well as quality of life, improves.

 

Posterior Capsulotomy

A posterior capsulotomy is a laser procedure that sometimes is necessary after cataract surgery.

During cataract surgery, part of the front (anterior) capsule of the eye's natural lens is removed to gain access to and remove the lens. The clear, back (posterior) capsule remains intact and supports an intraocular lens (IOL), a plastic or silicone disc that is implanted in the eye and replaces the natural lens. As long as that capsule stays clear, you will experience good vision. But in about 10% to 20% of cases, the posterior capsule may lose some of its clarity. When this happens, the doctor can create an opening in the capsule using a laser, thereby restoring normal vision. This procedure is called a posterior capsulotomy.

Before the laser procedure, the doctor will have done a thorough eye examination to make sure there is no other reason for vision loss.

The posterior capsulotomy is painless and takes approximately five minutes. Eye pressure is measured 30 minutes after the operation to make sure it is not elevated.  Vision usually improves within the next 24 hours.

 

Multifocal and Accommodative Intraocular Lenses to Treat Cataract

When you have a cataract, the lens of your eye becomes cloudy. Light cannot pass through the lens easily, and your vision becomes blurred.  Cataract and implant surgery takes about 15 minutes and is an outpatient procedure.  It is usually done with topical anesthesia (drops to numb the eye) and mild intravenous sedation (medicine to help the patient relax).  The surgeon makes a few small incisions close to the edge of the cornea and then inserts a small, ultrasonic instrument to break up the center of the eye's natural lens, which is then vacuumed out through one of the incisions. The surgeon folds and inserts the intraocular lens implant (IOL) through the same incision. These incisions are usually self-sealing, requiring no stitches.

The most common type of IOL is the monofocal or fixed-focus IOL . The monofocal lens helps you attain clearer vision at one distance. Note that eyeglasses and contact lenses are still required in order for you to see clearly at all ranges of distance.

Another type of IOL is the multifocal IOL . The multifocal lens has several rings of different powers built into the lens. This type of implant allows the individual to see at a range of distances.

A third type of IOL is the accommodative IOL . The accommodative lens has a hinge designed to work with your eye muscles, allowing the lens to move forward as the eye focuses on near objects and backward as the eye focuses on distant objects. This movement allows you to focus at different distances.

 

Phacoemulsification

Phacoemulsification (Phaco) is a surgical method used to remove a cataract, which is a clouding of the eye's naturally clear lens. A cloudy lens interferes with light passing through to the retina, the light-sensing layer of cells at the back of the eye. Having a cataract can be compared to looking at the world through a foggy window.

In phacoemulsification, an ultrasonic oscillating probe is inserted into the eye through a very small incision, which usually does not require suturing. The probe breaks up the center of the lens. The fragments are suctioned from the eye at the same time.  Most of the lens capsule is left behind and a foldable intraocular lens (IOL) is implanted permanently inside to help focus light onto the retina. Vision returns quickly and one can resume normal activities within a short period of time.