Cataract Questions

What is a cataract...? What causes a cataract...? When should a cataract be surgically removed...? What surgical procedures are required to remove a cataract...? Why should a cataract be surgically removed...? What surgical procedures are used to remove a cataract...? What do cataract surgery entail...? Can a cataract come back...?

What is a Cataract...?

A cataract is the clouding of the eye’s lens that can cause vision problems.

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What causes a Cataract...?

There are several causes of cataracts.  Age is the primary cause, however many other factors may increase the speed at which a cataract progresses, such as excessive sunlight exposure, certain drugs such as steroids, diabetes, and a family history of early cataracts.  Even some children are born with cataracts.

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When should a cataract be surgically removed...?

Although cataract removal may be recommended because of the appearance of the lens or specific eye problems, it is important that you understand the options in treating cataracts.

Occasionally, your eye doctor may say "your cataract is not ripe enough" or it "is too ripe." These expressions refer to chemical changes the cataract undergoes as it ages. As the condition progresses, the protein of the lens slowly changes, frequently becoming very hard (nuclear) or very soft (cortical). Your eye doctor may suggest surgery before the cataract is allowed to age too long (get too ripe), in order to allow greater choice in surgical procedures.

When a cataract has been diagnosed, consider how your vision affects your quality of life and ability to do the things you ordinarily do. Unless a cataract interferes with work, driving, reading or leisure activities, there is usually no urgent need to remove it, particularly if the condition affects only one eye. There's no harm in waiting if you keep regular appointments with your eye doctor to evaluate how the cataract is progressing and whether or not surgery can be safely postponed. When glasses or magnifiers no longer help, or both eyes develop a cataract, surgery in the eye with the worst acuity is the only option. There is no medicine or other treatment that can dissolve or remove the cataract.

Once the decision to have surgery is made, your eye doctor will discuss your chances of achieving a good visual result based on the results of preoperative tests.

The benefits of surgery depend on the health of your retina and optic nerve at the time the procedure is performed. For the majority of people having cataract surgery, vision is restored, perhaps requiring only prescription glasses for distance or reading and sunglasses. When you have other eye conditions, you may still need special optical devices, like magnifiers, after the surgery. However, you may be able to use optical devices with less magnification and find it easier to see without the haze and blur caused by the cataract.

Routine preoperative procedures

A-scan

The A-scan is an ultrasonic probe that measures the length of the eyeball and provides the data to calculate the power of optical correction of the lens implant. Although some doctors use a multifocal or bifocal type of plastic lens implant, most choose a plastic or silicone implant set for distance vision. Within certain limits, it's possible to choose the type of sight you prefer. For example, a very nearsighted person may choose to be less nearsighted (to see at a distance without glasses) as long as the vision in the operated eye still closely matches the nonoperated eye. Otherwise, the inequality of vision will result in visual confusion. This consideration is particularly important if the cataract is only in one eye. Similarly, people who wear glasses to correct farsightedness (hyperopia) may elect to see at a distance without glasses. In this instance, reading glasses will be needed for close work.

Medical evaluation

It is customary to have a thorough medical checkup within the two-week period prior to surgery. If you have high blood pressure, a heart condition, or diabetes, it's important to consult your internist before surgery in case your medication schedule needs to be modified before and/or on the day of surgery. This is particularly true with diabetic medication and with heart conditions requiring blood thinners.

Informed consent

Your ophthalmologist is required to review possible complications with you regardless of their low incidence. Complications often sound frightening but their probability is rare in these days of modern technology and skill.

Optional preoperative tests

Some preoperative tests are recommended only in special situations.

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What surgical procedures are required to remove a cataract...?

Performed by an ophthalmologist in a hospital or surgical center, cataract surgery is an elective outpatient procedure. During surgery, the lens is removed and replaced with an artificial one (implant) that performs the same function.

Two types of surgical procedures are commonly performed: extracapsular extraction and phacoemulsification. The extracapsular method has been the standard for over a decade, but with advancing technology in surgical equipment and intraocular lens implants for both methods, phacoemulsification has gradually become the procedure of choice in the majority of cases. The ophthalmologist usually makes the decision at the time of the diagnostic evaluation based on the dilation of the pupil, the state of the lens, the effect of other eye problems such as glaucoma on the mechanics of the eye, and the history of previous eye surgery.

Not all cataracts can be removed by phacoemulsification. If a pupil is too small and doesn't dilate, the lens is too hard, the cataract is too advanced, the eyeball is too deep set or the brow too prominent, then the extracapsular method, which requires stitches, is preferred. Eventually, after about six weeks and once stitches are removed, postoperative vision is comparable with either method.

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What does cataract surgery entail...?

Extracapsular extraction

1. Incision at the border of the cornea and sclera of about ½ inch

2. Opening of the lens capsule to expose nucleus

3. Lens nucleus removed from capsular bag in one piece

4. Cortical material removed by aspiration (suction)

5. Plastic lens implant placed in the capsular bag

6. Eye sutured with seven to nine nylon stitches

7. Postoperative astigmatism due to stitches

8. Removal of some of the stitches after six or more weeks to reduce astigmatism

9. Corrective glasses after stitches are removed, or when astigmatism subsides (usually six to seven weeks after surgery)

Phacoemulsification

1. Small tunnel incision of 3/16 inch under a conjunctival flap in the sclera or directly in the cornea into the anterior chamber

2. Opening of the lens capsule to expose nucleus

3. Lens nucleus fragmented and removed from capsular bag by ultrasonic emulsification and suction

4. Cortical material removed by aspiration (suction)

5. Plastic lens implant placed in the capsular bag

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Can a cataract come back...?

A cataract can't come back, but a "secondary membrane" or thickening of the elastic lens capsule can form within weeks or months of surgery. This causes your vision to become slightly cloudy. It occurs in about 40% of cases and is easily and permanently removed through a procedure called a YAG capsulotomy, which uses a special cutting laser. The procedure takes approximately five minutes and is done with anesthetic drops on an outpatient basis by an ophthalmologist. In this procedure, a small opening is  in the capsule behind the lens implant so that light can again reach the retina. The procedure is painless but you need to have your eye pressure checked the next day. In addition, you must use eye drops for a few days. Your eyeglass prescription will not change.

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