What is a cataract?
A cataract is a cloudy or opaque area in the normally clear lens of the eye. Depending upon its size and location, it can interfere with normal vision.
Most cataracts develop in people over age 55, but they occasionally occur in infants and young children. Usually cataracts develop in both eyes, but one eye may have somewhat worse vision than the other.
Early symptoms of cataracts include blurred vision, glare and difficulty reading. Cataracts generally progress very slowly, and surgery may not be needed for many years, if at all. In some cases, periodically changing your eyeglass or contact lens prescription may continue to provide you with good vision.
There is no way to prevent cataract development. Currently, the only way to treat cataracts is to surgically remove the natural lens in the eye.
When is cataract surgery necessary?
Waiting to have surgery usually won't harm your eyes. When considering cataract surgery, you need to ask yourself:
- Can I perform my job and drive safely?
- Do I have problems reading or watching television?
- Do vision problems affect my level of independence?
When your vision has decreased to the point where you can no longer easily and safely perform daily activities, then it's time to consider cataract surgery.
Your doctor of optometry can assist you in making that decision. He or she is most familiar with your current and past eye health and vision and can answer any questions you may have about cataract surgery. Following a comprehensive eye examination, your optometrist can advise you on the potential benefits and risks of cataract surgery.
If you decide to proceed with cataract surgery, your optometrist can help you find a qualified cataract surgeon in your area. In many cases, your optometrist will also provide the follow-up care you will need as your eyes heal after surgery.
How is cataract surgery performed?
Cataract surgery is a procedure used to remove the natural lens in the eye when it becomes clouded. The natural lens is replaced with a plastic, artificial lens that is permanent, requires no care, and can significantly improve vision. Newer artificial lenses can have the natural focusing ability of a young lens, allowing for distance and some near vision, as well.
Cataract removal is one of the most frequently performed surgical procedures in the world. The surgery is typically an outpatient procedure that takes less than an hour. Most patients are awake during the procedure and need only local anesthesia. If you need to have cataracts in both eyes removed, you will typically have two separate surgeries. This way, the first eye can heal before the second eye surgery.
There are two types of cataract surgery:
- Small incision cataract surgery involves making an incision in the side of the cornea (the clear outer covering of the eye) and inserting a tiny probe into the eye. The probe emits ultrasound waves that soften and break up the lens into little pieces so it can be suctioned out. This process is called phacoemulsification.
- During this procedure, the surgeon removes the cataract but leaves most of the thin outer membrane of the lens, called the lens capsule, in place. The incision made for this procedure is so small that the surgeon generally does not need to use sutures to close the opening.
- Extracapsular surgery requires a somewhat larger incision in the cornea to allow the lens core to be removed in one piece. This approach may be used if your cataract has advanced to the point where phacoemulsification can't break up the clouded lens. Through this incision, your surgeon opens the lens capsule, removes the central portion of the lens and leaves the capsule in place.
Once your surgeon removes the natural lens, he or she generally replaces it with a clear plastic lens called an intraocular lens (IOL). The IOL is placed in the lens capsule that was left in the eye. The artificial lens can focus light onto the back of the eye and improve vision.
When implanting an IOL is not possible because of other eye problems, contact lenses and, in some cases, eyeglasses may be able to correct vision.
Intraocular lenses come in three basic forms: monofocal, astigmatic (toric), and multifocal lenses.
- Monofocal lenses are the most commonly implanted lenses. They have the same power in all areas of the lens. They can have a fixed focus or allow for changes in focus.
- Fixed Focus Monofocal IOLs can provide excellent distance vision. However, since these lenses have a fixed focus set for distance vision, you may need to use reading glasses for good near vision.
- Accommodating Monofocal IOLs are a relatively new lens option that can be used for patients who want both good distance and near vision without the use of eyeglasses or contact lenses. These lenses also have a single focusing power. However, they can shift from focusing on distance objects to focusing on near ones by physically moving inside the eye in response to the focusing action of the eye muscles.
- Astigmatic (toric) IOLs have astigmatism correction in them. They can be used for patients who have a lot of astigmatism and want to reduce it.
- Multifocal lenses are like bifocal eyeglasses. Several areas of the lens have different powers, which allow individuals to see clearly at far, intermediate and near distances. However, these multifocal lenses are not suitable for everyone. For some individuals, they may cause more problems with night vision and glare than monofocal IOL lenses.
The type of intraocular lens implant that will work best for you will depend on your current vision status and your vision and lifestyle needs. Your optometrist and cataract surgeon can advise you on the most suitable lens implant.
What are the risks of cataract surgery?
Cataract surgery is one of the safest and most successful surgical procedures available. While rare, complications after cataract surgery can occur. Most problems can be treated successfully, but significant vision loss can occur. The complications include:
- inflammation or infection of the eye
- bleeding in the eye
- swelling of the cornea
- detachment of the retina
- increased pressure inside the eye
- dislocation of the implanted lens
- accumulation of fluid in the retina
- drooping eyelid
The risk of these complications is greater for people who have other eye diseases or serious medical problems.
In addition, cataracts can mask additional eye problems, such as retinal damage, that neither the doctor nor patient is aware of before the surgery. In these cases, the success of the cataract surgery may depend on the treatment of the other problems.
Cataract surgery can potentially contribute to the progression of age-related macular degeneration (AMD), a degeneration of the central part of the retina. Therefore, AMD patients with cataracts must weigh the potential risk of losing central vision against the visual improvement provided by cataract surgery.
What happens after cataract surgery?
Normally you can go home the day of your surgery, but you won't be able to drive. You might need help for a few days because your doctor may limit activities such as bending and lifting.
It is normal to feel itching and some mild discomfort after cataract surgery. You may also have temporary fluid discharge from your eye and be sensitive to light. Avoid rubbing or pressing on your eye. Try not to bend from the waist to pick up objects on the floor. Do not lift any heavy objects. You can walk, climb stairs and do light household chores.
Your doctor may prescribe medications to prevent infection and control eye pressure. After a few days, your eye should be comfortable. Often, your eye will be completely healed within about eight weeks.
During this healing time, your eye health and vision need to be monitored. In many cases, your optometrist will co-manage your follow-up care with the doctor who did the cataract surgery. Typical follow-up visits occur 1 day, 1 week, 3-4 weeks, 6-8 weeks and 6 months after surgery.
Once your eyes have healed, your optometrist can evaluate if you need eyeglasses or contact lenses for optimum vision. Most people need to wear glasses after cataract surgery, at least for some activities.
If you did not receive an accommodating or multifocal intraocular lens implant, you will also need a lens prescription for reading and close work. This may be reading glasses, bifocal or progressive addition lenses (no-line multifocals), or monovision or bifocal contact lenses.
Following cataract surgery, you will still need regular eye and vision exams to monitor your eye health and vision. If you had cataract surgery on only one eye, your optometrist can continue to monitor the other eye and help you arrange for surgery on the second eye, when needed.
What is a secondary cataract?
You may have heard about a condition called "secondary cataract" or "after-cataract." This occurs when the lens capsule, the membrane that wasn't removed during surgery and supports the lens implant, becomes cloudy and impairs your vision. Another term for this condition is posterior capsular opacification (PCO).
A secondary cataract can develop months or years after cataract surgery. You may feel like the cataract is returning because your vision is blurry again. Cell growth on the back of the capsule gradually clouds your vision.
There is no way to know who may develop clouding of the lens capsule after cataract surgery. Up to 50 percent of cataract surgery patients experience this problem.
Treatment for a secondary cataract is fairly simple. It involves a technique called YAG laser capsulotomy, in which a laser beam makes a small opening in the clouded capsule to allow light through. It is a painless outpatient procedure that usually takes less than five minutes. Afterward, you might stay in the doctor's office for about an hour to make sure your eye pressure doesn't increase. Generally, most patients immediately experience improved vision, while some experience gradual improvement over several days.