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Cataract surgery is performed routinely every day throughout the world. In developed countries it has become one of the most technically advanced areas of modern medicine. The type of cataract surgery performed in the past was often a trying ordeal involving a long hospital stay with considerable discomfort and an even longer recovery period. The only choice would have been to wear cumbersome cataract glasses to compensate for the surgically-removed lens. Today, everything has changed. The development of advanced surgical techniques involving sutureless small incisions and high quality lens implants have made cataract surgery one of the most successful forms of treatment offered by the medical profession. The operation can be performed either on a day-case or in-patient basis, either under local or general anaesthesia depending on the preferences of the patient, the consultant and clinical considerations.
For the majority of patients the procedure is virtually painless, with a recovery period of just a few days. The vision provided by a lens implant (an intraocular lens - IOL) is as clear as that provided by the natural lens of the eye. What is a cataract?
Light enters through the curved, clear window at the front of the eye, the cornea. The iris acts like a camera diaphragm to control the amount of light entering the eye. The iris controls the size of the pupil. The diagram shows the interior of the eye as seen from the side. Incoming light rays are bent by the cornea and the lens of the eye so that they focus on the retina. A clear, sharp image formed on the retina is essential for a person to be able to see clearly. A cataract is a clouding of the normally clear lens of the eye which interferes with the normal passage of light rays to the retina. The result is a general dimming of vision which becomes progressively more blurred as the density of the cloudiness increases.
A cataract is not a film over the eye, caused by straining the eye, or a cause of irreversible blindness.
There may be other factors which contribute to a loss of vision: for this reason the eye must be carefully examined before any operation to ascertain whether or not other conditions exist and determine how they affect the patient's sight e.g. glaucoma, age related macular degeneration. Even if other conditions do exist, removal of the cataract and its replacement with a lens implant should ensure that vision is improved to its best possible level and that any further deterioration of vision by the developing cataract is stopped. Once a cataract appears, it almost always continues to become more cloudy. The only treatment is removal by using one of the most successful forms of surgery available today. What causes cataracts to form? Various conditions can cause cataracts to form: heredity is the determining factor in congenital and juvenile cataracts. Certain eye injuries, chronic diseases such as diabetes or other specific eye diseases can also cause cataracts. It is for this reason that a simple urine test should be done on patients presenting with cataracts to exclude diabetes as a possible cause. By far the most common cause is simply ageing. As we grow older, the lens gradually loses its water content and increases in density. These natural processes may set the stage for cataract formation. According to some estimates, by the age of 65 nearly 50% of the population develop the earliest form of cataracts. Some degree of cataract formation is expected in virtually everyone over 70 years of age. The time required for development of the cataract is anywhere from a few months to many years. It may stop at an early stage of development and vision is then not significantly affected. In other cases, the cataract continues to develop and interferes with vision. What are some of the symptoms? Blurred vision that worsens over a period of months or even years is the key symptom. Some people notice that things seem dim with one eye and brighter with the other, and printed images may seem distorted. Colours become less distinct and many patients are bothered by glare. No pain, itching or redness is associated with cataract formation; such symptoms may indicate other forms of eye disease or infection. Cataracts usually develop in both eyes but they may develop at different rates, so vision in one eye is often significantly better than in the other. Can cataracts be prevented? Is there a cure? Despite extensive and on-going research, there are no known means of preventing cataracts developing as part of the ageing process. No diet, drugs or medicines have been proven to delay or cure the developing cataracts. Surgery is the only way to remove the cloudy lens. This always involves an incision into the eye. Cataracts are not removed with a laser, an intense beam of light energy. Ophthalmic laser surgery can, however, be used after cataract surgery to open part of the lens membrane (the posterior capsule) which may become cloudy after cataract surgery. A cataract, once removed, cannot recur. When should surgery be performed? Under ordinary circumstances, cataract surgery is not an emergency procedure. There are only a few, rare instances where immediate action is needed, for example if the cataract has swollen and caused a secondary glaucoma. Otherwise, it is a matter for the patient to decide if and when to have the operation. In the past, surgeons usually waited until the cataract reached a mature stage to remove it (until it was ' ripe '). However, modern surgical advances have now made it possible to perform this operation at any stage, usually as soon as the clouded lens begins to interfere significantly with the patient's comfort and normal daily activities. It is in fact now easier and safer to perform cataract surgery at an earlier stage. The time to have surgery depends on the individual patient's visual requirements. The desire to keep a driving licence in an elderly patient, or occupational needs in younger patients mean that the decision will probably be made sooner rather than later.
The only treatment for cataracts is to surgically remove the affected lens. In order to restore satisfactory vision, a replacement for the lens must be provided. Three methods of replacement can be used: cataract glasses, contact lenses or intraocular lenses. 'Cataract glasses'In the past, 'cataract glasses' (aphakic glasses) were the only available means of lens replacement. Today they are hardly ever required except for infants with congenital cataracts. However, using them required considerable visual readjustment, for they magnify everything one sees about 30% making things appear closer than they really are. They also gave the wearer a tunnel vision effect, reducing side vision and causing visual distortion. For the person who had surgery on only one eye, cataract glasses could not be used because of these magnification problems. Contact LensesContact lenses eliminate some of the problems experienced with cataract eyeglasses. The wearer notices a much smaller degree of magnification (estimates range between five and ten percent). Contact lenses also eliminate the tunnel vision effect and can be used successfully when either one or both natural lenses have been removed surgically. However, the greatest obstacle to the use of contact lenses is learning to successfully remove and insert the tiny lenses. Older patients, particularly those who have arthritis or tremors in the hands, find this task more difficult. New long-wear contact lenses may solve this problem for some patients but there remain many who cannot successfully wear them. Intraocular Lenses
An intraocular lens, or lens implant, is the most effective method of restoring vision. Following the removal of the cataract, an intraocular lens is placed in the same position as your natural lens, inside the capsular bag of the cleaned out cataract. It remains there permanently. The implanted lens offers significant advantages over glasses or contact lenses. First, magnification is reduced to the natural level. Like the contact lens, the intraocular lens gives full peripheral 'side-to-side' vision, so good depth perception is retained. The lens, which is made of perspex or silicone, is placed inside the eye at the end of a routine cataract operation. It is left there permanently and never has to be inserted or removed by the patient. Following implant surgery, vision is usually very good immediately and begins to further improve over the course of the next few days.
Day case surgery Cataract surgery can be undertaken on an out-patient basis under either local or general anaesthesia. Modern general anaesthetics are short-acting with rapid recovery. As long as the patient has mobility and family or friends support with transportation, almost any patient may have their cataract surgery on this basis, provided they attend for an early postoperative examination the following day. Later follow-up examination is usually at one to three weeks and again five to six weeks after surgery.
The area around the eye is cleansed and sterile drapes are placed over your face. The eye is held open with a special instrument and microsurgery is carried out under a powerful surgical microscope to enable the delicate structures within your eye to be clearly seen. The operation generally takes approximately half an hour. The incision into the eye is usually very small indeed and the cataract is removed by a delicate probe (a process referred to as phacoemulsification - see diagram) and stitches are usually not necessary.
Regardless of the procedures used and care taken, there is always a possibility of complications. These are relatively rare and when they do occur, the problem can usually be corrected. However, unexpected serious complications such as infection (endophthalmitis), retinal detachment, macular oedema may occur and cause a permanent decrease in vision. These complications are very rare, but this is the reason that cataract surgery should not be regarded as a minor undertaking. After Your Operation After having one of the most delicate microsurgical operations in modern medicine, you should be able to resume most activities almost immediately. However, a short period of convalescence is required and some care is necessary to ensure proper healing. Vision usually improves within a few days and although complete healing of the eye takes several months, an eye test 2 to 3 weeks after the operation may allow glasses to be prescribed at that stage. It is not unusual for corrective lenses to need a power change some time during the post-operative year as the eye completes its healing. Vision usually continues to improve as the eye heals. It is sometimes difficult to persuade a healthy, active person that he or she is a post-operative patient with physical limitations. You must accept this fact so that any complications can be avoided. Complications are usually much easier to avoid than to treat. After Leaving Hospital
How to Use Your Medicines Take your medicines as directed. Make sure you understand exactly how to take or use them and ask for further advice if you have any doubts. If you miss doses, don't try to 'catch up' by taking two or three missed doses at once. Keep your medicine in a cool, dry place. Medicines can change with age if they are stored in a warm, damp place. Keep the container tightly closed. Remember: Read the instructions carefully. Make sure you understand them and follow them at all times. How to Use Your Eye Drops Read the instructions on the bottle.
Note: It may be helpful to use a mirror or ask someone else to help you. The preparation is free from germs before use - keep it clean. Store upright in a cool place. Keep all medicines out of reach of children.
For more information go to: www.faceandeye.co.uk
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