Most adults can expect- to experience some degree of gradual clouding of vision as they age and many do experience significant vision loss. That’s why cataract removal is one of the most common surgical procedures. Fortunately, the most common type of cataract surgery is an outpatient procedure involving minimal anesthesia, tiny incisions, quick recovery, and very high success rates.
How cataract develops
Sight begins when light passes through the rounded, outer surface (cornea) of your eye and through the black circle (pupil) in the middle of your eye. Next, light passes through your lens, which focuses the light that produces images on the membrane (retina) at the back of your eyeball (see diagram on Page D-2).
The lens is where cataracts develop. A normal lens is crystal clear, but most people’s lenses begin to cloud with age. Clouding is the result of a normally clear arrangement of protein fibers in your lens that begin to break down and lose their transparency. Small areas of one or both lenses begin to cloud at first, and you may not be aware of any vision change for some time. However, the clouding generally spreads and becomes denser.
A cataract scatters the light that enters your eye and prevents a sharp, focused image from reaching your retina. The result may include:
• Increasingly blurred or dim vision
• Increasing difficulty with night vision
• Sensitivity to bright light and glare
• Seeing halos around lights
• Double vision in one eye
Why it is difficult to prevent
Age is the single greatest risk factor for cataracts. By age 65, about half of all people will have developed some degree of lens clouding, which may or may not impair vision. In many cases, cataract development can’t be avoided. However, you may be able to blunt the impact of additional risk factors by:
• Stopping smoking and wearing eyeglasses and a wide-brimmed hat. Smoking and exposure to ultraviolet (UV) light lead to the production of unstable molecules called free radicals. These can damage the cells of the lens. Choose sunglasses that block 99 to 100 percent of both ultraviolet A (UVA) and ultraviolet B (UVB) light. The materials used to make lenses of normal eyeglasses block anywhere from about 60 to 99 percent of the UV light, with high-index plastic and glass, and polycarbonate plastic providing the most UV protection.
• Eating a healthy, plant-based diet. A plant-based diet is naturally loaded with antioxidant vitamins, which can help neutralize free radicals. However, there’s no conclusive evidence that enhancing your vitamin intake with supplements helps prevent cataracts.
• Taking care of health problems. Following a treatment plan for certain medical conditions, such as diabetes, may help reduce your risk of eye problems. However, if your medical problem involves prolonged use of corticosteroids, realize that this may increase your risk of cataracts.
The only way to know if you have cataract is to have an eye exam. Using a variety of tests, an eye doctor can identify lens clouding and determine how dense and visually significant it is. In addition, it is important to test for other eye problems that can impair vision, such as diabetic retinopathy, glaucoma or macular degeneration.
If you’re diagnosed with cataracts, you and your eye surgeon can decide whether surgery is right for you. There’s often no rush. Cataracts develop slowly and, except for certain, uncommon circumstances, delaying surgery won’t cause damage to other parts of your eye.
In the early stage of the disease, using different eyeglasses, magnifying lenses or stronger lighting may work well enough for you to put off surgery. However, when cataracts begin to affect your quality of life, such as your ability to drive or read, it may be time to consider surgery.
Before surgery
Surgery to remove a clouded lens and replace it with an artificial lens is the only treatment for cataracts. Before performing surgery, your eye doctor uses ultrasound imaging to measure the shape of your eye. These measurements are used to determine the appropriate power for the lens implant.
The standard lens implant used in cataract surgery has a single focal length (monofocal), meaning the implant lens can’t adjust for both distant and close-up vision as can the natural lens. You and your surgeon typically have a discussion before the operation as to which type of lens is best for you. If a distance lens is implanted, you’ll need to wear glasses for reading. If a reading lens is implanted, you’ll need glasses for long-distance vision and night driving.
However, newer multifocal lens implants have recently been approved that can provide good vision at more than one distance without the aid of eyeglasses. Studies have shown that most people who have multifocal lenses have improved vision at various distances, but with this versatility, there can be a trade-off in vision quality. For example, your distance vision may improve with a multifocal lens but not as much as it would have with a monofocal lens corrected for distance alone. In addition, some with multifocal lenses experience glare, halos around the lights, and loss of contrast.
During surgery
Most people remain awake during cataract surgery although sedation is typically used. Anesthetic eye drops or injections are often all that’s used to numb the eye during surgery. The surgery is usually an outpatient procedure and is done on only one eye at a time. Altogether, you may spend several hours in the outpatient or hospital facility, but the surgery itself typically lasts less than an hour.
The most common method of cataract surgery is phacoemulsification. During this procedure, your surgeon makes a 1/8-inch incision in your cornea and inserts a needle-thin probe into your lens. The rapidly vibrating probe softens and breaks up the clouded lens using ultrasound energy. Contrary to popular belief, laser energy is never used in this process. The lens pieces are then removed by suction. Left behind is the clear, outer layer (capsule) of the lens, which helps support the implanted (intraocular) lens. The intraocular lens commonly used with phacoemulsification is flexible, similar to a soft contact lens. This is folded, inserted into the eye and then unfolded to full size. Most often, no stitches will be needed to close the tiny incision.
If your cataract has advanced beyond the point where phacoemulsification can’t effectively break up the clouded lens, a larger 3/8 to 1/2-inch incision may be made so that your surgeon can remove the clouded lens with a different procedure. A larger incision may also be made if a rigid, non-foldable intraocular lens is needed to replace your natural lens. The larger incisions require stitches and often involve a longer period for healing.
After surgery
Complications after cataract surgery, such as infection, bleeding, inflammation, and swelling, are relatively rare and most can be successfully treated. Within the first few days after surgery, any mild pain or discomfort should diminish and disappear while your vision steadily improves. Any changes for the worse — such as increased pain or vision changes or loss — require immediate evaluation by your eye doctor.
After your eye has had several weeks to heal, you’ll probably be fitted with prescription glasses or contacts to fine-tune your vision.
Thanks to advances in medical science, surgery to remove a cataract is very successful. In an otherwise healthy eye, cataract removal results in improved vision 95 percent of the time.