Cataract

Glossary

Cornea - eye window
Pupil - aperture
Lens - light is focused onto the retina
Retina - the picture sensing film of the eye
Optic nerve - the cable which sends the picture from the retina to the brain
Brain - interprets the picture

What is a Catarct and what are the Symptoms?

Nature’s lens inside the eye is no longer clear. This means that the light passing through it is scattered and reduced, this results in glare, blur, ghosting, sometimes double vision even when one eye is closed and dimness of contrast and colour. In the early stages, there is often a change in power of the eye which requires a change in glasses power to correct. However there comes a time when a change of glasses no longer provides the necessary quality of vision to manage or meet the driving standard.

Why has it occurred?

Most cataracts develop as part of the ageing process, late 50’s 4%, late 60’s 20%, late 70’s 40%, late 80’s 65%.Other factors increase the risk of cataract: diabetes, steroid treatment, poor nutrition, life threatening diarrhœa, smoking and alcohol, high sunlight exposure.

How does the eye make a picture?

In the same way a camera does (see glossary).

Which eye will be operated on?

Usually the eye with the poorest vision is operated on first, unless this is a weak eye for different reasons.

Who may benefit from Cataract surgery?

Anyone with reduced vision will be considered if the poor vision is due to cataract rather than ageing of the light sensitive (‘seeing’) retina.

Age, frailty, or poor health is not a bar.

How is Catarct treated?

So far there is no known drop or tablet that can prevent or treat cataract. The opaque natural lens of the eye is removed from its supporting bag and then a clear plastic lens implant is usually implanted into the supporting bag (capsule).

How successful is Cataract surgery?

Usually it is very successful, very safe and effective. Patients should be willing to take a one in a hundred risk of serious complication (such as sight threatening infection). If they are not then cataract surgery will be postponed.

What are the risks?

1 in 100 patients might develop a sight threatening complication.*If this should occur in an only eye then it could result in loss of all vision.

1 in 10,000 might develop a life threatening complication.

Will i have a general or local anaesthetic?

A decision is usually made according to the patient’s preference. The majority of cataract operations are done under local anaesthetic, (awake but no pain). This method has less risk to general health than general anaesthetic. (asleep). The rare risks of injected local anaesthetic are: spread of the anaesthetic to the brain, which can cause breathing to stop, then an anaesthetist would take over the breathing until it wore off,(1 in 500 to a 1000 patients). Needle puncture of the globe occurs as infrequently, it can lead to bleeding inside the eye or retinal detachment. These may require further surgery to treat.

Eye drop anaesthesia. It is possible to abolish the pain of surgery with eye drops only, this avoids the complications of injected local anaesthetic, however it makes the surgery more difficult because the eye can still move during surgery.

How long will i stay in hospital?

Nowadays the majority of cataract is done as day case local anaesthetic surgery, that is patients go home on the same day as surgery. It is safe for patients to be on their own at night after local anaesthetic cataract surgery. Normally a check-up is performed a day or 2 days after your operation.

What i do while awaiting admission?

Continue your present daily activities.

Stop driving unless you have been advised to continue.

If you smoke, STOP, so that you will be fitter for surgery.

What happens before the operation?

Your eye will usually be measured to calculate the power of the implant lens, however lens power errors do occur.

If a general anaesthetic is planned you will have routine blood tests, heart tracing and sometimes a chest X-ray.

You will be seen by an anaesthetist. Sometimes surgery is cancelled or postponed if this assessment is unfavourable.

You will be asked to sign a consent form before surgery.

What happens on the day of the operation?

You should be accompanied by a relative or friend

If you are having a general anaesthetic, you will go without food or drink for at least six hours before your operation.

You will receive eye drops to dilate the pupil.

You will be taken to a waiting area where your name, consent and treatment charts will be checked.

After a while you will be moved to the anaesthetic room, where you will have a safety needle put into a vein on the back of your hand and receive a sleeping agent (general anaesthetic) or an injection to freeze the eye or anaesthetic drops.

The operation will last between 20 and 40 minutes. The eye is dressed and then you will be moved to a recovery area, before returning to the Ward.

You should be accompanied by a relative or friend home.

What problems can occur during surgery?

Surgery may prove difficult due to collapse of the front chamber or iris prolapse (0.7%). Then the surgeon may need to change the method by making a larger incision, or cut out a sector of the iris (iridectomy).

Bleeding can occur in the lids or white of the eye from the anaesthetic injection. Bleeding can occur inside the eye (hyphema and choroidal hæmatoma 0.07%),this can rarely be large enough to cause serious disruption of the structures in the eye (expulsive hæmorrhage).

The lens may not be completely removed from its bag if fragments remain hidden (1%) or if the bag breaks (capsule rupture). It is possible to lose the bulk of the lens into the back part of the eye through a bag break, then the lens may come to lie against the retina, then it would require further surgery to remove (vitrectomy). Similarly the new lens implant may rarely fall back out of position (0.06%),or be imperfectly positioned.

If the bag breaks it may allow vitreous gel to come forward and be lost from the eye (4.4%), then a front half vitrectomy would be done at the time of cataract surgery.

At the end of surgery the eye is checked for any leaks. Sometimes these only show after surgery as persistent watering (0.25%).

How will i feel after the operation?

When your eye dressing is removed to instill drops the same day you will notice things are brighter and more colourful, but your vision will probably be blurred. Vision may be disappointing if there is also pre-existing ageing of the retina.

Best vision is usually achieved at approximately 3 months after surgery. Some weeks after the surgery you will be referred to your Optician for glasses.

What is the daily routine thereafter?

You will be given eye drops to be instilled into the operated eye four times daily, usually for 1 month or until the bottle is finished. A return appointment will be made for you.

When can i return to work?

Non-physical work can start 1-2 weeks after surgery. Sport and heavy work can be started 3 months after surgery.

What about the other eye?

Second eye surgery can be discussed with your surgeon. Most patients are keen to have their second eye operated on to balance their vision and return a broad field of view, 3D vision and improve the sharpness of vision for driving with both eyes open.

What problems may develop after surgery?

Soon after surgery, occasionally there may be stitch irritation or droopy eyelid or swollen itchy lid/eye-drop allergy. Hazy vision may be due to distortion or œdema (9.5%) of the cornea (window of the eye) This œdema may be caused by raised pressure (7.9%). Blurred vision may also be due to blood inside the eye or imperfect lens power of the implant or retinal problems, such as cystoid macula œdema.

Rarely the retina may detach (0.14%) from the eye wall and cause floaters or a black curtain across part of the vision. Most problems following cataract surgery are treatable but endophthalmitis (0.14%), infection inside the eye, usually results in a serious defect in vision. It begins with pain and reduced vision, sometimes a yellow fluid level can be seen in front of the lower part of the coloured part of the eye (iris).

Months later a reduction in vision is usually the result of ageing of the retina, or thickening of the old lens bag (capsule) occurs in up to 50% by 5 years after surgery . The thickened capsule can be cleared (capsulotomy) with a painless laser light as an out-patient. Rarely a persistent cornel œdema is due to a poor lining of calls on the back of the cornea, (bullous keratopathy).

What are the dont's?

Don’t rub or wipe your eyes for 6 to 12 weeks, gently dab with a CLEAN TISSUE if necessary.

You can lead a normal life, but avoid any direct injury to the eye.

What are the do's?

Do wear your glasses or sunglasses for added protection.

Do enquire about other daily activities such as driving.

Do read and watch television if you are able.

Do bathe and shave but prevent soap and water from entering the eye.

Do remember to take your drops and keep your clinic appointments.

Do consult your G.P. if you find it difficult to instill your drops.

Do return immediately if you notice any WARNING SIGNS

Warning Signs

PAIN, PRICKING SENSATION

GREEN OR YELLOW DISCHARGE

DETERIORATION OF VISION

INCREASED REDNESS

SHOWER OF FLOATERS

BLACK CURTAIN LIKE VISION DEFECT

Multifocal Implant

Cataract surgery removes a defective lens from the eye and replaces it with a new artificial lens. The majority of lens implants performed in this country are monofocal. That is, have only one fixed focus. Sometimes the focus is set for near so that reading vision is possible without glasses but glasses are needed for distance vision. Alternatively the implant can be chosen to give better distance vision, however reading glasses are required.

The multifocal lens offers the advantage of having acceptably good focus for near and distance so that glasses are only required if there is significant astigmatism.

This offers an advantage to racket players, golfers, card players and people who have hobbies where changing focus from near to distance is infrequent, such as musicians.

In those patients who prefer to continue to wear bifocal for astigmatic correction, then looking through the lower segment of the bifocal with a multifocal implant in the eye, permits a magnifying aid making it easy to do fine work such as thread needles.

The multifocal implant offers the best chance of being able to manage without bifocal spectacles after surgery.

This technology is offering more than simply treating the cataract by also providing a range of focus, which had been lost from mid life onwards. This range of focus is not possible with the usual type of implant.

The disadvantage of the multifocal implant is that some patients are sometimes aware of a ghost image, this is the cost of restoring focus for different distances. This is probably because the brain is receiving a slightly different quality of image from each eye and so there is some rivalry between the eyes. Indeed if this problem is noticeable after the first surgery then early second eye surgery with multifocal implant offers the best hope of abolishing the symptoms.

When both eyes have had multifocal implant, 8% still need to wear glasses all the time, 50% occasionally and 41% of patients never wear glasses.

Links

Back to Eye Parts

This information site has been provided by varied UK and US eye doctors for patients with eye problems.

Once your eye doctor has made a diagnosis or recommended an investigation or treatment, then you will be able to find further explanation on this site.

It is not a self diagnosis centre. It should not be relied upon without taking professional advice.