Conditions: Cataracts

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Cataract surgery has become one of the most technically advanced areas of modern medicine. The development of advanced surgical techniques involving 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.

Mr Leatherbarrow has performed modern small incision cataract surgery for over 16 years as a consultant ophthalmic surgeon.

What is a cataract?

	The interior of the eye as seen from the side

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.

Common misconceptions about cataracts

A cataract is not a film over the eye, caused by straining the eye, or a cause of irreversible blindness.

	A cataract as seen with the pupil dilated

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 see 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 have a ghosted outline. Colours become less distinct and many patients are bothered by glare. particularly from the sun or oncoming headlights. 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.

 

Driving
View through a clear lens		Cataract induced glare

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.

Will I have to wear glasses after surgery?

This depends on your individual needs and whether or not you have a cataract affecting one or both eyes. This will be discussed with you at your consultation.

Intraocular Lenses

	Eye with intraocular lens as seen from the side

In order to restore satisfactory vision following removal of a cataract, a replacement for the lens must be provided. This is achieved with the use of an intraocular lens, or lens implant. Following the removal of the cataract, an intraocular lens is placed in the same position as your natural lens, inside the capsular bag that contained the cataract . It remains there permanently.

The power of lens implant is decided by a special test referred to as biometry which is performed on admission to hospital or sometimes beforehand. This is a special ultrasound test and is performed by a specialist nurse technician or optometrist. There are different types of lens implants.  Some offer distance and near vision (multifocal lenses) but these are more expensive and have some disadvantages. This will be discussed with you at your consultation.

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.

Intraocular lenses or implants

 

A lens implant which has just been placed in the eye

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.

What happens in surgery?

If you are having a local anaesthetic the anaesthetic solution is injected around, not in, the eye after the surface of the eye is numbed with drops. The area around the eye is cleansed and sterile drapes are placed over your face with oxygen flowing underneath. 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).

Can there be complications?

Regardless of the procedures used and care taken, there is always a possibility of complications. These are very rare indeed 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.

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 a few weeks, an eye test 2 to 3 weeks after the operation may allow glasses to be prescribed at that stage if they are needed at all. 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. 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 that can be downloaded as a PDF file go to my clinic website at www.faceandeye.co.uk

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