Q: What is a cataract?
A: A cataract is defined as a clouding of the lens of the eye that causes reduced vision.
Q: What causes a cataract?
A: Aging is the usual cause of cataract. Sometimes cataract may be caused by an injury to the eye or as a result of some other eye disease. Occasionally it may be due to the prolonged use of steroid medications. Patients with diabetes may develop cataract at an earlier age than would otherwise have been the case. There are other rarer causes e.g. inherited, congenital or due to a systemic condition.
Q: How does a cataract affect my vision?
A: As the lens of the eye becomes less clear and hazy it obstructs and scatters the light that enters the eye. As a result the image that reaches the retina at the back of the eye becomes dimmer and less clear. The effect on vision can vary from patient to patient depending on the exact nature and severity of the cataract.
- There may be a sense that you are just not seeing as well as you used to, even with new spectacles.
- You may have difficulty recognizing faces at a distance or across the road.
- Things you look at may have blurred edges or a ghosting around them. Things may even seem to be double.
- Your vision may vary depending on the lighting conditions. If there is a bright light behind you then the vision may be quite good. However if the bright light is in front vision can be terrible. The effect is rather like driving a car with a dirty windscreen. When the sun is to the rear then the screen seems reasonable clear. However when driving into the sun the scatter of bright light from the dirt on the screen can be blinding.
- There may be a change to color vision. Colors become less intense and washed out.
- Sometimes when the cataract is just beginning, and before there has been much impairment to vision, there may be a change in the focus of the eye. After many years when the focus of the eye had been pretty stable you may find the need to visit the optician repeatedly for a change in spectacles.
Q: How is a cataract diagnosed?
A: A cataract may be spotted by an optometrist, general practitioner or an eye specialist (Ophthalmologist). To diagnose and assess a cataract a thorough examination of the eyes is required and this may involve the following:
- Measurement of vision (visual acuity). You may be asked to read an eye chart with and without spectacles and when looking through a pin hole.
- The pressure within the eye may be measured. This usually involves using an anesthetic eye drop and lightly touching the window of the eye.
- The pupil may be dilated with drops to allow a better view of the cataract and the back of the eye. It is important to check for any eye disease other than cataract as if present this may influence the decision to operate or not.
Q: Can cataract be removed with laser?
A: No. The cataract itself can only be removed by surgery. This is because the cataract must be physically removed from the eye. Laser can be used to treat posterior capsular opacity (after cataract).
Q: Can cataract be prevented?
A: There is no firmly agreed consensus about this. There is some evidence that antioxidants (e.g. vitamins A, C & E) may delay the development of cataract. These substances are present in a well balanced healthy diet. Not smoking may also help deter cataract.
Q: If I think I’ve got a cataract what should I do?
A: You will need to see an ophthalmologist (eye specialist) with expertise in cataract surgery. Your optometrist (optician) or general practitioner (GP) will be able to refer you to one. For private care it is possible to contact an ophthalmologist directly although a referral letter from your GP is helpful as this may provide general medical information that may be relevant to surgery.
Q: I’ve been told that I have a cataract but that it is too soon for surgery. Why?
A: Many cataracts develop very gradually. A slight cloudiness of the lens of the eye may be noticed before the patient themselves are aware of any visual problems. If vision remains good enough for the individual patient’s lifestyle requirements then it is often reasonable to leave the cataract alone. These days cataract surgery is usually very successful. However the operation should not be performed without good reason.
Q: When is a cataract operation needed?
A: The timing of a cataract operation should be tailored to the individual patient’s vision requirements. Some patients will need and want a cataract removed sooner than others. For example if the patient wishes to continue to drive then a cataract will need to be removed when it is still relatively mild.
Similarly a mild cataract may need to be removed in order to allow the patient to continue safely with their job. However if the patient is very elderly with less demanding visual requirements then it may be appropriate to leave a cataract until it is more advanced. The decision to operate or not should be based on the particular circumstances and wishes of each patient.
It is not necessary to wait until the cataract is ‘ripe’ before surgery can be performed. This is an outdated concept that no longer applies.
Q: Are cataracts found only in old people
A: No, but most cataracts seen by eye specialists are in older patients. This is because age is the main cause of cataract. Cataract can occur in younger people if, for example, it is due to an injury or has been inherited or was due to an infection whilst in the womb. Rubella (‘German Measles‘) may cause cataract & deafness in the baby if the mother contracts the illness during the early stages of pregnancy.
Q: Do I need a letter from my GP in order to see an eye specialist about my cataract?
A: The traditional and well established system is that your General Practitioner (GP) will refer you to an eye specialist (Ophthalmologist). The GP will write to the specialist about your case and may include details supplied by your optician. In some places there are now systems for direct refer from your optician to the eye specialist, whilst keeping your GP informed of this.
If you are seeking treatment for your cataract as a private patient it is possible for you to make an appointment with the eye specialist directly yourself. A letter from your GP is not essential but is helpful. Your GP may be able to provide important background and medical information to the specialist. Also your GP may be able to help you decide which private eye specialist you would like to see and advise you on how to go about doing this.
Q: What does a cataract operation involve?
A: A cataract operation involves removing the natural lens from the eye, which has become cloudy, and replacing it with a tiny artificial plastic lens. This is called the lens implant. Over the years the surgical technique has evolved and improved. These improvements have brought about more rapid recovery after surgery with good vision achieved sooner. Most cataract operations performed in developed countries now use a procedure called ‘phacoemulsification’. Eye doctors often simply call the operation ‘phaco’.
Q: Can I have both cataracts treated at the same time?
A: Most eye surgeons will only operate on one cataract at a time. This is the safest thing to do. If both cataracts are removed at the same time there is a small risk that a complication could occur affecting both eyes; e.g. an infection. This could then lead to profound loss of vision in both eyes.
There are special circumstances when one might operate to remove both cataracts at the same time. For example if a patient requires a general anesthetic but is only fit to go through the ordeal once.
Q: What anesthetic will be needed for the operation?
A: Nowadays most cataract operations are done using only a local anesthetic and without an overnight stay in hospital. This simplifies the procedure and minimizes the risk to the patient’s general health. There are a number of different techniques for administering the local anesthetic. The precise technique used will depend upon surgeon and patient preference and the nature of the cataract.
Q: If I have a local anesthetic will the operation hurt?
A: The surgery should be pain free. The surgeon is as keen as the patient to achieve this because a relaxed patient is the key to good operating conditions. There are though some sensations. Some eye drops sting briefly as may the local anesthetic injection if one is used. Some patients may be aware of a stretching sensation from the clip that holds the eyelids open during the operation. There may be an awareness of a light pressure from the fluids and instruments in the eye and the touch of the surgeon’s hands around the eye.
A common practice is for a member of staff to hold the patient’s hand during the operation. By squeezing this hand the patient can draw attention if any pain or distress occur. Any problems can then be addressed. The patient should avoid speaking during the operation unless given the OK to do so by the surgeon. This is because when speaking the head and the eye may move and at the wrong moment this might upset the surgery.
Q: Should I take my usual medication on the day of the operation?
A: It is best to check will your eye unit about this. The pre-operative assessment is a good time to do this. Arrangements may vary from one eye unit to another and from one anesthetist to another so it is not possible to give all encompassing advice. Some medication (e.g. regular blood pressure tablets) should be taken as usual, some medication (e.g. anticoagulants like Warfarin) may need to be stopped several days before surgery, and special arrangements may apply to some medication (e.g. those for diabetes).
Q: Will I be able to see what is being done to the eye during the operation?
A: No. If a local anesthetic injection is used this will put the sight (vision) to sleep as well as removing feeling and paralyzing eye movement. Even if only anesthetic eye drops are used the bright light of the operating microscope will tend to bleach vision and the surgical maneuvers are so close to the eye that there is little if any visual appreciation of what is happening. The other eye will be covered.
Q: How successful is cataract surgery?
A: If cataract is the only disease within the eye then there is a high probability of regaining normal vision after the operation once the eye has fully recovered from the surgery. Cataract surgery is a safe and successful procedure. As with any operation there can be no guarantee of a successful outcome but serious complications are rare. The chance of having worse vision after the operation due to some problem related to the surgery is perhaps of the order of 1 in 200.
After a cataract operation most people will still need some form of (new) spectacles to obtain perfectly focused vision. If only one eye has been treated there may be a period of adjustment for the brain to learn to comfortably use the eyes together again.
Q: What are the risks of having a cataract operation?
A: There is a small risk in having any operation. This is also true for a cataract operation. In the hands of an experienced surgeon the risk of ending up with worse vision as a result of the surgery is small; perhaps of the order of 1% or less. The risk of losing all vision or of requiring removal of the eye after the operation (e.g. because of an infection) is extremely remote; but it is not zero. The types of risk involved in having a cataract operation include:
- Infection within the eye.
- Bleeding within the eye.
- Disturbance to the retina, e.g. a retinal detachment or a swelling of the centre of the retina (which affects central vision). The latter is called cystoid macular edema.
- Permanent clouding of the cornea. The cornea is the window of the eye.
- A long term increased pressure within the eye.
- A drooping of the upper eyelid.
These complications are rare. If they occur further surgery to the eye may be required. It should be emphasized that in the vast majority of cases cataract surgery is uneventful with excellent results. However this cannot be guaranteed.
Q: Can the operation go wrong?
A: In a small minority of cases technical difficulties can occur during cataract surgery. The delicate structures around the cataract sometimes break. This can make it more difficult to remove the cataract and/or safely insert a lens implant. For example the very thin membrane behind the cataract may rip. This is called ‘posterior capsule rupture‘. This membrane separates the cataract from the vitreous jelly which fills the main cavity of the eye. If this membrane breaks the vitreous jelly can move forward into the front part of the eye.
Additional surgical steps are then necessary to remove this misplaced vitreous. If these events are correctly dealt with the visual outcome is still favorable in most cases. Occasionally it is safer not to insert a lens implant when these complications occur, although this may be possible at a later date. Very rarely the cataract may fall to the back of the eye during surgery. Referral to a vitreo-retinal surgeon in order to remove it will then be necessary. Again it should be emphasized that in the vast majority of cases cataract surgery is uneventful with excellent results. However this cannot be guaranteed.
Q: What is the intra ocular lens implant?
A: The intra ocular lens implant (referred to as the IOL by eye surgeons) is a clear plastic artificial lens inserted into the eye once the cataract has been removed. It replaces the natural lens which has been removed from the eye. Nowadays inserting a lens implant is an integral part of a cataract operation. Without a lens the eye remains wildly out of focus.
In the past thick very strong spectacles or a contact lens were used to refocus the eye after cataract surgery. With an intra ocular lens these are not required and the lens implant can be forgotten about by the patient. Ordinary spectacles may though still be necessary to obtain perfectly focused vision. There are different types of lens implants and they can be made from a range of plastic materials.
Q: How long will the lens implant last?
A: A lifetime. The plastics from which the lenses are made have been subject to accelerated aging tests. It is estimated that in the eye the lens materials will last in excess of 150 years before showing signs of significant degradation. There have been some rare reports of certain lens designs becoming prematurely opaque within the eye. These lenses have been withdrawn from the market.
Q: Will the lens implant move?
A: If the surgery was routine and without complications it is extremely unlikely that the lens implant will move out of position.
Q: Will I need an over night stay in hospital?
A: In most cases no. The vast majority of cataract surgery is done on a day case basis. Occasionally it may be necessary to stay in hospital overnight following surgery, for example if a general anesthetic is given towards the end of the day.
Q: What restrictions are there after the operation?
A: You should avoid any situation where you might be hit in the eye and you should not rub the eye. Modern small incision (key hole) cataract surgery means that the eye is very robust after the operation. The wound is extremely unlikely to give way. It is OK to bend and do light physical activities almost immediately after the operation.
If such activities cause the eye to throb then it is wise to stop and rest. For small incision suture-less cataract surgery normal activities and past times can usually be fully resumed after about three weeks. If a larger sutured incision has been used it may be 2 or 3 months before this can be done; always check with your surgeon if you are in doubt.
Q: How soon after the operation will I be able to drive?
A: This depends. If you have driving standard vision and a normal field of vision in the fellow (non operated) eye then you may legally drive a private car on the day following the operation. However if you have been used to driving using two eyes it is wise not to drive until good vision has returned to both eyes or you have adapted and are confident to drive with only one eye.
The time taken for the eye to regain driving standard vision after a cataract operation varies from one patient to another. Sometimes driving standard vision may be regained within days of the surgery but this cannot be guaranteed in advance. Sometimes new spectacles will be required in order to obtain driving standard vision. It is best to ask your surgeon and not to drive until he or she has stated that your vision has reached the required standard. Do not drive until the effects of the anesthetic or any sedation have worn off.
Q: How soon after the cataract operation can I go back to work?
A: This will vary from patient to patient. It depends on the nature of your work and the speed of recovery of the eye. Your own ophthalmic team will advise you. There are though some general principles.
These days most cataracts are removed using a small incision technique without the need for sutures. With this form of surgery the eye usually takes about three weeks to fully settle. For sedentary occupations, it may be acceptable to return to work after about a week. For work involving physical exertions 2 to 3 weeks may be preferable. If the job requires good quality well focused vision then the patient should wait until this is achieved which in some cases will not be until new spectacles have been obtained.
If the surgery has involved a larger incision with sutures, then the eye may take 2 to 3 months to fully settle. In these cases the return to work may be delayed somewhat.
When returning to work (and at other times too) avoid situations where you might be hit in the eye. Dry or dusty atmospheres may cause some irritation to the eye but are not directly harmful.
Q: How soon after the operation will I be able to play sport or swim again?
A: This will vary from patient to patient. Your ophthalmic team will be able to advise you.
The type of surgery will affect how soon these activities can be resumed. These days most cataracts are removed using a small incision technique without the need for sutures. With this form of surgery the eye usually takes about three weeks to fully settle. If the surgery has involved a larger incision with sutures, then the eye may take 2 to 3 months to fully settle.
It may be wise to wait until the eye has fully healed before returning to swimming and sports although opinions do vary somewhat between surgeons. Contact sports and small ball games (e.g. tennis, squash, badminton) represent the greatest threat to the eye as they carry a risk of a direct blow to the eye.
The chlorine in swimming pools and the salt in the sea may irritate the eye a little more than normal in the first weeks after surgery but are unlikely to be directly harmful.
Q: For how long will I need eye drops after the operation?
A: In most cases for 3 to 4 weeks, though occasionally it may need to be for longer than this.
Q: How soon after a cataract operation can I fly?
A: There are no restrictions on flying after cataract surgery. It is quite safe to do so. The air conditioning in an airplane may cause some dryness but it does not result into any serious damage. However do not fly away from post-operative supervision until your ophthalmic team are happy that the eye has sufficiently recovered from surgery.
The only condition in which flying may not be appropriate after an eye surgery is when a bubble of expansile gas has been left in the eye. This is not done during routine cataract surgery. It is sometimes done for operations on the retina. Gas within the eye will expand at altitude.
Q: Will I need to wear an eye patch afterwards?
A: Yes, most eye surgeons do require patients to wear an eye patch and/or a plastic shield over the eye after cataract surgery. If a local anesthetic has been used the patient may not be able to properly close the eye for a few hours following the surgery. A soft eye patch/pad is then used to keep the eyelids gently closed over the eye until the ability to blink has fully returned. A plastic shield is also used to protect the eye from accidental pressure. This is usually kept in place over the eye until the day after surgery (i.e. through the night).
If a small incision without sutures has been used many surgeons then dispense with the shield though some recommend continuing with it during sleep for several days. If a larger incision was used with sutures the wound is more vulnerable and it may be wise to continue to wear the shield during sleep/at night for a week or so.
Q: Will I still need glasses after the operation?
A: Yes, in most cases. The operation may change the focus of the eye and new spectacles may be required once the eye has fully recovered from the surgery. If the focus is set for distance vision, then reading spectacles may be needed and vice versa. Multifocal lens implants are used by some surgeons though these are not suitable for all patients. With such a lens implant it may be possible to manage without spectacles after the cataract has been removed.
Q: Can a cataract come back?
A: No. Removing a cataract involves permanently removing the cloudy natural lens from the eye. However usually a thin membrane, called the posterior capsule, is left behind at the time of surgery. This membrane is clear immediately after the operation. It can though become hazy and opaque in the months and years following the operation. If this occurs it will reduce vision. This can seem like the cataract coming back. This is called “posterior capsule opacity” or “after cataract”. It is very simple to treat with laser. The laser makes a central hole in the membrane which again clears the line of vision. This is painless and takes just a few minutes and is done as an outpatient.
Photo by National Eye Institute