No one knows for sure why the eye’s lens changes as we age, forming cataracts. But over time the lens, which lies behind the iris and the pupil, begins to cloud. This clouding of the lens is a cataract.
In a healthy eye, the lens works much like a camera focusing light onto the retina at the back of the eye. It adjusts the eye’s focus letting us see things clearly. The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. As we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract and over time it may grow larger and cloud more of the area making it difficult to see clearly.
Some of the symptoms of cataracts are: slightly blurred vision, like looking through a cloudy piece of glass; light sensitivity causing glare and sensitivity to lights at night; or diminished brightness of colors.
The only way to be sure you have a cataract and to determine the proper treatment is to see your doctor for an eye examination. Initially, visual aids such as updated glasses, magnification and appropriate lighting may improve your vision. Eventually, you may be advised to consider cataract surgery, a surgical treatment to remove the clouded lens and in most cases replace it with a clear, plastic intraocular lens (IOL). Cataract surgery is the most frequently performed surgery in the United States with over 1.5 million surgeries done each year. Nine out of 10 people who have cataract surgery restore their vision to between 20/40 and 20/20, good enough to pass a driver’s test in most states.
A cataract is a cloudiness of the eye’s natural lens.
About half of the population age 65 and older, have a cataract and nearly everyone over 75 has at least one. In rare cases, infants can have congenital cataracts. These are usually related to the mother having German measles, chickenpox, or another infectious disease during pregnancy. Cataracts can also form as a result of an injury to the eye.
Your doctor is probably advising you to wait until the cataract grows to the point of interfering significantly with your vision. You need to continue to visit your eye doctor regularly to monitor the cataract’s progress. Some cataracts never quite reach the stage where they should be removed. If your cataract is interfering with your vision to the point where it is unsafe to drive, or doing everyday tasks is difficult, then it’s time to discuss surgery with your doctor.
All surgery involves some risk. However, cataract surgery is the most commonly performed type of surgery in the United States. Many surgeons have performed several thousand procedures. Choosing a surgeon who is experienced will reduce the risk of something going wrong. For a full list of risks and benefits of cataract surgery, please refer to your doctor.
There are two principal methods. Extracapsular extraction, the most commonly performed cataract procedure, removes the natural lens. The lens is suctioned out, or broken into pieces with ultrasonic waves (phacoemulsification), then suctioned out. Usually a replacement lens (IOL) is inserted.
Intracapsular extraction is performed much less often; this is when both the lens and membrane holding the lens in the eye are removed to ensure that the membrane won’t eventually grow cloudy and interfere with vision. When the membrane becomes cloudy, or if any bits of remaining natural lens become cloudy, this is called a secondary cataract. The problem with intracapsular extraction is that the membrane is no longer there to receive a replacement lens.
YAG lasers are used in a later procedure to create a clear opening in the lens-containing membrane if the membrane becomes cloudy in the months following the original cataract removal. Also, a new laser received FDA approval in 2000 as a tool to break up the cloudy lens instead of using ultrasound. The lens particles are then suctioned out of the holding membrane in the usual way.
Cataract patients who have intraocular lenses (IOLs) implanted during surgery to replace the focusing power of the lens, may need reading glasses for close vision. People who don’t receive IOLs may wear contact lenses for distance vision and reading glasses for close work. Or they may wear multifocal lenses for all distances. Rarely does anyone have to wear thick eyeglasses.