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The prospect of getting cataracts should not be a great cause for concern. The discouraging problems and unsuccessful solutions are in the past. Today’s advanced methods of surgery enable a quick restoration of sight to most eyes with cataracts. The techniques used by many surgical specialists remove the cataract so effectively that vision, in an otherwise healthy eye, may be as clear and bright as when you were young.
A cataract is a cloudiness that slowly develops in the naturally clear lens inside the eye. As this cloudiness becomes more dense, the lens loses its ability to function. Instead of focusing light into the eye, it begins first to distort and then block light from entering the eye. Vision becomes increasingly difficult as a cataract develops.
A cataract is not a white film that grows over the eye as many people think. It is not a new growth of any kind. It is simply a change in the protein material of the eye’s lens. The natural lens is a round pill-sized capsule suspended inside the eye. Its function is to focus light that enters the eye. The lens consists of a transparent outer capsule filled with a clear protein gel. These soft elements make the lens flexible so it can change shape to focus on both near and far objects.
Cataracts form in the internal gel of the lens. The outer capsule stays clear. Cataract cloudiness does not necessarily form in both eyes at the same time or in the same way. One eye may develop a mature cataract months or years before the second eye. Some cataracts form within a few months. Others develop over a period of years.
Cataracts develop most often because of age-related changes inside the natural lens. Throughout life, new protein gel is being produced on the inside of the lens capsule. This gel gets compressed as the years go on and at some point, in each eye cloudiness begins to develop. This hardening and clouding may reach the point where the lens is completely white and light can no longer enter the eye.
Heredity (a family history of the condition) seems to determine when these age-related cataracts develop, just the way it determines other factors such as when hair turns grey. Cataracts can form at any time of life for reasons other than aging. They may develop after a serious eye injury. The use of certain drugs, exposure to harmful chemical or radiation, some eye diseases and conditions such as diabetes can also cause cataracts to form earlier than usual. Babies may be born with cataracts for various reasons.
Since cataracts vary in their development from person to person, the symptoms also vary. Some of the most common symptoms people experience are:
These symptoms do not necessarily mean a cataract is present. Other eye disorders can cause similar effects. But these signs definitely mean an eye examination is necessary from a medical eye doctor.
There is no known way to prevent cataracts or to make the cloudy lens clear after a cataract has developed but modern surgery offers a solution to the problem. If there are no other serious problems with the eye, cataract surgery by an ophthalmic surgeon can restore sight. Surgery can be performed as soon as cataracts begin interfering with a person’s lifestyle.
There are two main parts to the surgery. First, the cloudy contents of the eye’s natural lens must be removed. And second, the lost focusing power of the lens needs to be replaced with a new lens.
Removing the cataractUsing the most advanced method of surgery, the surgeon first makes a small 3 mm (1/6 inch) incision in the white wall of the eye or in the clear cornea, just under the top eyelid. Delicate forceps are inserted into the eye through the pupil to create a smooth round opening in the front of the lens capsule.
The surgeon then uses an ultrasonic probe, vibrating about 40,000 times per second, to break up the clouded gel. A vacuum tube in the centre of the probe suctions the cataract material out of the eye. In this way, the whole lens capsule can be cleaned out with little disturbance to the eye. The lens capsule is left intact, except for the opening in the front, because it helps keep the eye healthy. It also makes a good pocket in which to place a new lens.
Cataracts are not removed with a laser, as many people believe. Lasers are used for many eye procedures, but they cannot remove something from an eye, as is necessary with a cataract. In the future, lasers may be used to soften cataracts before surgery.
The clouded gel that is removed from the lens capsule once served as the eye’s fine focusing element. After it is removed, it must be replaced or the person will still not be able to see clearly. Surgeons replace this lost focusing power with a new manufactured lens.
These lens implants are designed to fit securely in the cleaned out lens capsule. They have two flexible arms on the side to hold them in place. Most lens implants are made of a pure form of plexiglass. Holding the lens with an instrument, the lens is inserted through the capsule opening and positioned correctly. The incision is then closed.
People who have surgery should be able to see fairly well the day after the operation. The lens implants need no care and continue to provide focusing power for life. Lens implants are made in many focusing powers, so surgeons can select one that suits the requirements of each person.
Out-of-hospital surgeryIn the past, patients had eye tests in one location and then went to hospital for a few days for surgery. Now, there is another option, day surgery. Most surgeons perform cataract surgery on a day-surgery basis at hospitals or surgical centres so patients can leave shortly after their surgery. Only the eye and the area around the eye are anaesthetized. Some doctors offer topical anesthesia, using drops only.
Across North America, increasing numbers of people are having cataract surgery in private surgical centres completely away from the hospital. These private centres offer many benefits, including convenient scheduling, a comfortable environment and a lot of personal attention. Some even allow families to stay with patients during the surgery for interest and support.
Normally when light enters the eye, it first passes through the cornea, the eye’s front window. The cornea begins to bend the light rays toward a focal point. Light then enters the inner part of the eye through the pupil, it reaches the natural lens, the eye’s fine focusing element. The lens finishes the work that the cornea started by bending the light rays even more so they converge and focus on the retina at the back of the eye. The sensitive retina encodes the light images into electrical impulses and sends them through the optic nerve to the processing centre of the brain where they are interpreted into clear, colourful sight.
The natural lens consists of a clear outer capsule filled with an originally transparent gel that functions as a focusing element. The whole lens, about the size of an ordinary pill, is held suspended behind the coloured iris by flexible strands called zonules. These zonules are the ligaments attaching the lens to the ciliary eye muscle. Contraction and relaxation of this muscle varies the tension on the lens capsule to change the thickness of the lens and provide a full range of focus. The ability to focus on near objects is gradually lost as the lens becomes older and less flexible. This is why reading glasses are often needed between 40 and 50 years of age.
Gone is the time when cataract surgery meant days flat on your back in bed, with eyes bandaged. Cataract surgery these days is quick and efficient. If you realize that your vision is not as clear as it once was, see your family doctor who can tell you if cataracts are forming in your eyes.
FAMILY HEALTH is written with the assistance of |
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