Today, we know more about cataracts than we did in the past, and we have more effective ways to treat them. Cataract surgery is now the most common operation in the U.S.. This year more than one million Americans will have this procedure. It is also one of the safest.
What is a cataract?
A cataract occurs when the lens, located just behind the iris, becomes opaque. The lens is the size and shape of an M&M candy. Light must past through this lens to get to the retina. A cataract interferes with the transmission of light. When this lens becomes opaque, light rays are no longer precisely focused on the retina, so it is similar to looking through frosted glass, rather than clear glass.
What is the function of the lens?
A tiny muscle called the ciliary body, which runs around the inside of your eye like a miniature rubber band, adjusts the shape of the lens. When the ciliary body contracts, it changes the shape of the lens from thin to fat. A thin lens focuses at distance; a fat lens focuses at near.
Why does the lens lose its ability to focus as people get older?
When you are young, your lens is small. As you grow, it grows too, adding a new layer of cells to its surface each year, much like a tree adds rings to its trunk. Unlike the rest of your body, however, the lens never stops growing. Your lens will eventually become so bulky that it will no longer be able to focus at near. When this happens, usually between ages 40-42, you will need reading glasses (magnifiers) to read. This condition is called “presbyopia”; or “elderly eyes”.
How common are cataracts?
Cataracts are common. By age 70, everybody will develop at least a slight cloudiness of their lens, and over half will have opacities so dense that they will no longer be able to read, drive, and see clearly.
Aside from age, what else causes cataracts?
In addition to age, cataracts can be caused by:
- Prior eye surgery, for example, for retinal problems such as macular holes
- Diabetes, if your blood sugar is not in good control
- Prolonged exposure to bright sunlight, without the protection of sunglasses or a hat
- Exposure to ionizing radiation, for example that used to treat cancer
- Trauma (cataracts are common in boxers)
- Some medications, for example, Prednisone, which is often an ingredient in asthma inhalers, and is used to treat inflammatory diseases such as rheumatoid arthritis
- Family history
How can I prevent cataracts?
Don’t smoke. Avoid exposure to second hand smoke. Wear UV blocking polarized sunglasses and a hat in bright sun. Wear eye protection during sports. If you are diabetic, watch your blood sugar.
How many people get cataracts?
The National Eye Institute reports that cataracts are present in 50 percent of people age 65 to 74 and 70 percent of those aged 75 and older. However, not all cataracts affect vision significantly or require treatment.
At what age do cataracts usually develop?
Cataracts can develop at any age, although they become more common as people age. Very rarely, a baby is born with a cataract. This baby’s pupil will be white instead of black. The cataract should be removed before the child is 6 weeks old. The child must have a device to restore the focus of the eye. Some surgeons may recommend that a lens be implanted inside the eye. Others may recommend a contact lens after the surgery. The other eye will be patched periodically. This strengthens the operated eye.
How will I know if I have a cataract?
Cataracts are painless. Because most cataracts develop very slowly, people often don’t recognize the signs. Cataract symptoms include:
- difficulty reading road signs while driving
- difficulty following a ball e.g. in golf or tennis
- trouble reading small print
- trouble telling blue from green or grey
- problems recognizing faces
- seeing halos around lights when you drive at night
- seeing double even if you close one of your eyes
- becoming bothered by glare
- vision worse in bright light
- increasing nearsightedness, with frequent changes in eyeglasses prescription
If you have any of these symptoms, you may indeed be developing a cataract. Since there are different types of cataracts, and each type causes different vision problems, you probably will not have all of these symptoms.
A nuclear cataract, which is in the central part of the nucleus of the lens, usually causes increasing nearsightedness. A cortical cataract, which is located in the cortex, which surrounds the center of the lens, usually has symptoms of diffuse blurriness. A posterior subcapsular cataract, located at the back of the lens in the rear lens capsule, causes glare in bright light and difficulty reading.
More than one type is often present in the same eye. Posterior subcapsular cataracts are often associated with the use of certain drugs, such as Prednisone, and with eye inflammation and eye trauma. Nuclear cataracts are frequently caused by smoking. Cortical cataracts are associated with prolonged exposure to bright light.
The extent of visual damage and how quickly vision is impaired depend on the size and density of the cataract as well as its location within the lens.
How can my cataract be diagnosed?
The only way to know for sure if you have a cataract is to have an eye examination by your ophthalmologist. The examination will include several tests:
- Visual acuity test
This test measures the sharpness of your vision, i.e. how clearly you see objects. A Snellen chart, which includes rows of letters and numbers that diminish in size, is used. Your eyes are tested one at a time, with the other eye covered. You are asked to read letters from across the room, usually 20 feet from the chart, but if the room is small, a different distance is used, with compensation.
You will be scored according to how well you see compared to someone with normal vision. Normal vision is 20/20. A score of 20/25 means that you see at a distance of 20 feet what a normally sighted person sees at 25 feet. You must have 20/40 vision in at least one of your eyes to get a drivers license in most states, including New York. You are considered legally blind if the vision in your best eye is 20/200.
- Slit lamp examination
A slit lamp allows the ophthalmologist to see the structures at the front of your eye under magnification. This specially designed microscope uses an intense line of light – a slit- to illuminate the cornea, iris, lens and the space between the iris and cornea. The ophthalmologist can see if the lens is clear, and how dense the clouding is.
- Retinal exam
A retinal exam will determine whether there are other problems, such as macular degeneration (a disorder of the center of the retina that is responsible for central, fine detail vision that might be causing your vision problems. Dilating drops are placed in the eyes to open the pupils wide and provide a bigger window to the back of the eye.
Your eyes will also be checked for glaucoma, a group of diseases characterized by excessive fluid pressure in the eye, which can damage the optic nerve.
Is there any way other than cataract surgery I can improve my sight?
During the early stages, lifestyle changes enable many people to cope with cataracts.
If you wear eyeglasses or contact lenses, make sure they are the most accurate prescription.
Wear UV-light- blocking sunglasses to reduce glare. The American National Standards Institute (ANSI) sets standards for sunglasses. Buy glasses that are labeled: “meets ANSI UV requirements”. This means they absorb 99 percent to 100 percent of all UV light up to 400 nm.
- Wear a hat with a wide brim when you go out in sunshine.
- Use a magnifying glass to read small print.
- Limit night driving.
- Use brighter lamps. Lamps that can accommodate halogen lights, 100 to 150 watt incandescent bulbs, help many people.
When should I have cataract surgery?
Although nonsurgical treatments may improve vision temporarily, they don’t slow the development of cataracts. Immediate removal of a cataract is not necessary however. Deciding when to have surgery should be considered carefully. You and your ophthalmologist should weigh the impact of the cataract on your daily life, the risks and benefits of the procedures, and the presence of other medical conditions that might affect the outcome.
Here are some questions to consider:
- Despite frequent prescription changes, am I having difficulty seeing with my glasses?
- Do I have difficulty performing duties at work because I cannot see clearly? For example, do I have to strain to read computer screens, or use magnifiers to see fine print in reports?
- Do I squint a lot?
- Have I cut back on reading or going to movies because it is hard for me to see?
- Am I afraid to drive at night because the car headlights interfere with my ability to see?
- Do I avoid driving during the day because of glare from the sun?
- Do I need help performing daily activities like cooking that demand clear vision?
- Am I fearful of falling because of my poor eyesight?
- Have friends and family complained about my poor eyesight and the impact it has on them?
- Have I put on a garment that I think is one color (e.g. black), only to be told by friends that it is another color (e.g. purple)?
How difficult and dangerous is cataract surgery?
Modern cataract surgery is one of the most effective surgical procedures in all of medicine. It offers more gain, for less pain, than almost any other type of surgery. It is astonishingly fast – about 11 minutes. If the eye is normal except for the cataract, surgery will improve vision in about 95 percent of cases. 85 percent of patients undergoing cataract surgery will attain vision of at least 20/40 – good enough to drive a car- one year after the operation.
Cataract surgery is extremely safe: there is less than a tenth of one percent chance of a serious complication. However, as in all surgery, the risk is not zero. Very rarely complications such as infection or bleeding can occur.
Cataract extraction is virtually always elective. DO NOT allow yourself to be rushed into the operating room. Schedule it when it is convenient for YOU, and only if YOU are convinced that you truly need it.
How should I choose my surgeon?
Extensive training is necessary to learn cataract surgery, and, like other surgeries, the more procedures you do, the better you get at doing them. Chose a surgeon who was trained in a major teaching hospital, and who does at least 8 of these procedures each month.
What should I do to prepare for surgery?
Today, cataract surgery is almost always performed under local anesthesia on an outpatient basis. Since you will have light sedation, somebody should come with you to take you home. You should not drive, or operate machinery, the day of your surgery. You may be asked not to eat or drink anything 12 hours pre-op.
If you are on Coumadin or other blood thinners, you do not have to stop taking these medications before your surgery. The incision will pass through the clear part of your cornea, which cannot bleed because it is devoid of blood vessels.
If you are a man who is taking Flomax for an enlarged prostate (a medicine that increases the flow of urine) you must stop taking it at least a week before surgery.
What happens during surgery?
Almost all cataract surgery today is done by phacoemulsification, although in rare cases an older technique called intracapsular cataract extraction (ICCE) surgery may be used instead.
In ICCE, the lens is taken out in one piece, and the replacement plastic lens is placed in front of, not behind, the iris.
During phacoemulsification, a miniature ultrasound machine is slipped into the eye, through an incision that is roughly the width of two pin heads. Phacoemulsification uses smaller incisions than the other techniques, which facilitates healing. The ultrasound device uses sound waves to shatter the cataract into fragments, turning it into a mixture resembling a thick milkshake. The machine then sucks these fragments out of your eye.
During phacoemulsification the “skin” around the lens, which is called the capsule, is carefully preserved. This capsule forms a tiny living pouch. A miniature clear, foldable, plastic replacement intraocular lens (IOL) is rolled up, like a taco, and slipped through the incision into this clear pouch.
Rarely, if an IOL is not appropriate for a patient, contact lenses or glasses are used post-op instead.
Tell me more about the IOL
The intraocular lens, or IOL, is made of PMMA, the same plastic that is used to form bullet proof shields and airplane windows. (We know it is safe in the eye, because many airplane pilots during World War II got fragments of windshields in their eyes during combat. These fragments still sit quietly in these eyes many years later, causing no problems.) This IOL requires no care. You will not feel it or see it. It becomes a part of your eye.
The power of the IOL will be chosen by measuring the curve of your cornea and the length of your eyeball. This power will determine whether the eye will be focused at distance, or at near, or in between.
Your surgeon may offer you one of the new, specialty IOL’s. It will not be covered by insurance, so you will have to pay an extra, out of pocket charge for it, which is usually quite steep.
If you have high astigmatism, you may be offered the AcrySof Toric. This IOL corrects up to 2 diopters of astigmatism. It will give you clearer sight when you are not wearing glasses. It must be oriented with great precision; if it is off axis by only 10°, there is a 33 % reduction in its effect. If it rotates after surgery so it is no longer positioned properly, you may need to have a second, minor surgical procedure to reposition it.
Two different specialty IOL’s are now available that enable you to accommodate from far to near, the way young people do.
The AcrySof ReSTOR has a focus that varies gradually from edge to center, somewhat like a multifocal contact lens. Unfortunately, this IOL can cause glare and halos around lights at night, so some surgeons no longer recommend it.
The Bausch & Lomb Crystalens flexes forward when the ciliary body contracts, so its focus changes from far to near. This IOL, like the ReSTOR, can cause glare and haloes in some patients. It also tends to stop moving over time, sometimes as soon as 1 year, which turns it into a one-focus IOL.
Your reading vision will not be perfect with this lens, so you will still need reading glasses. However, you will be able to focus from far distance to intermediate (computer distance).
What happens after surgery?
Because the incision is small, and specially constructed like a trap door, it will seal itself as soon as the phacoemulsifier is removed from the eye. There is no need for any sutures.
Your vision will improve quickly – in many cases, after a few hours; in some cases, after a few days. Most patients return to their normal activities within several days. Aside from slight scratchiness, itching, tearing and redness for a day or so, you will usually feel no pain, either during, or after, cataract surgery.
You will wear a patch over your operated eye for 24 hours, and, for several days, an eye shield at night to prevent you from accidently rubbing or poking the eye while you sleep. Because the eye is now more sensitive to sunlight, you will wear sunglasses while you are outside.
You will be taking several different drops several times a day for 4-6 weeks after your surgery. You will probably be told not to bend or lift heavy objects for a few days, and avoid strenuous activity. You may be told to take a tub bath instead of a shower for several days and to avoid washing your hair or swimming in public pools or hot tubs in order to keep dirty water away from your eye. You will probably be cautioned not to rub or poke the operated eye. Do not use eye make-up for several weeks.
Patients should contact their ophthalmologist if any of the following symptoms develop during recovery:
- Any sudden visual change
- Seeing bright flashes of light or floaters
- Increasing pain and redness
What power IOL should I chose?
Since you will have a new, different lens after cataract surgery, you have an opportunity to choose a different basic focus for your eye. If you do not have a cataract in your other eye, your surgery will match the refraction of the new eye to the old. If you had a big difference in focus between your two eyes, post operatively, the size of images would be huge, which would drive you crazy.
If you are having cataract surgery on both eyes, you must think carefully whether you would prefer to see best at distance, at near, or at one meter. Many patients chose the last option, since they will see quite well at distance, and quite well at near, without their glasses.
If you choose distance vision, you will need glasses to read; if you choose close or reading vision, you will need glasses to drive and watch movies.
You may also choose to have one eye set for distance and the other for near, but that is risky unless you have already experienced this vision while wearing contact lenses (so called “monovision”). It is safer to have both eyes the same.
Cataract surgery will NOT eliminate your need for glasses.
Laser Treatment for “after-cataract”
Usually within 5 years, and sometimes as soon as a few months, after your cataract surgery, you will develop cloudiness in the clear capsule that is holding your new lens in place, especially if your are under 50 years old. The cloudiness in the clear capsule is called “a secondary cataract” or a “secondary membrane” or an “after cataract”. This clouding occurs because the capsule is not inert, like Saran Wrap. It is living tissue which creates new lens fibers.
To correct this problem, a procedure called a “YAG capsulotomy” is used. A YAG (yttrium, aluminum and garnet) laser is used to create a hole in the center of the opacified capsule, so that you can look through it. The procedure is like wiping the frost off a window pane.
Completely painless, the procedure takes less than five minutes. A drop of topical anesthetic is placed in the eye, and then a contact lens is placed over your eye. You see a few flashes of light when the laser energy is applied. You can go home immediately, without an escort. Your vision should be better within a few hours.
Can I get cataract surgery on both eyes at the same time?
This is not a good idea. Wait at least two weeks. The first eye should have time to recover before surgery is done on the second eye. If any complications became evident in the first eye, the ophthalmologist might do the second operation differently.