The lens of the eye is responsible for focussing light that passes into the eye onto the retina. A normal lens is completely transparent and clear.
A cataract is a lens that is no longer transparent or clear. This may cause blurring of vision and difficulty seeing detail. It may also cause glare around bright lights, especially at night.
What are the benefits of surgery?
Cataract surgery aims to improve vision. This improvement is mainly the ability to read detail both close up and far away. It may also improve overall field of vision in some cases. Pre existing refractive error (short-sightedness or far-sightedness) may also be partly corrected at the same time.
What is cataract surgery?
Cataract surgery is an operation in which your lens is removed and a clear plastic man-made lens is inserted in its place. It is carried out in an operating theatre with specialist equipment. The technical term for the procedure is: phacoemulsification and intraocular lens implantation. On the day of surgery drops will be put in the eye to numb it and to dilate the pupil. In the operating room iodine will be used to clean the skin around the eye. Unless you are having a general anaesthetic (rarely used) local anaesthetic will be injected behind your eyelid to numb the eye. This will mean that you won’t feel or see anything during the operation (sub-tenons anaesthesia). A sterile drape will be placed over your face. This has a hole in it to enable access to the eye to be operated on. A small retractor will hold the eyelids open so you don’t have to worry about keeping your eyelids open. A tiny 2 millimetre incision is made in the eye. Through this and another even smaller incision, the lens is removed by choping it into small pieces. The device which chops it is called the phacoemulsification probe. It is a needle that vibrates at ultra sonic frequencies. After the lens has been removed, a lens implant is inserted. This implant is a plastic man made lens, the power of which has been carefully selected according to your biometry measurements pre-operatively and your desired post operative refraction (focus point). The lens implant stays in the eye forever and never needs to be changed. Usually no stitches are needed as the wound is self sealing. A clear plastic eye shield is taped over the operated eye. The whole procedure routinely takes no more than 15 minutes.
What anaesthetic will I need?
Most operations are carried out under local anaesthetic.
Subtenons anaesthesia: This is local anaesthetic. Anaesthetic drops are put in your eye, completely numbing the surface of the eye. Tiny sterile scissors are used to make a small cut behind the eyelid. A small injection of local anaesthetic is given behind the eyelid, through this small cut. No sharp needle is used reducing the risks of sharp needle anaesthesia. This anaesthetic not only numbs the eye but also stops it from moving and is a good choice if you are very anxious or don’t think you could keep your eye still during surgery.
General Anaesthesia is where you are completely asleep. This is not normally needed for cataract surgery but there are some people who want to be completely unaware during the procedure and for those a general anaesthetic is the best option.
Are there alternatives to surgery?
Cataract surgery is the most successful way of improving visual acuity in the presence of a cataract. If surgery is not wanted or not possible, vision can be optimised in other ways. A new pair of glasses may help. A low visual aid assessment can be carried out where you may try magnifying glasses and other devices aimed at improving reading. Using a light over your shoulder and directed onto your reading matter may help with reading
What will happen if I decide not to have surgery?
The cataract and your vision may stay the same or gradually get worse. A cataract does not damage the eye. In other words, leaving it un-operated does not make surgery in the future more difficult.
When should I have the operation?
The operation is carried out to improve vision. Therefore you as a patient should feel that there is a problem with your vision before having surgery. In other words, just because you have a cataract does not mean you have to have surgery. The risk of permanent loss of vision due to infection after cataract surgery is approximately 1 in 1000. A question you can ask yourself is : “Has my vision deteriorated to the point where I am happy to take a 1 in 1000 gamble with it?” It used to be the case that cataracts were best left until they were ‘ripe’. This is no longer the case - surgery can be carried out at any time.
What will happen before surgery?
Before the operation you will be seen in the clinic by Mr. McCormick. He will ask you about your vision problems. He will also ask about other medical problems you have, medications you take and any allergies (bring a list or the tablets themselves with you). He will examine your eyes. If you are to proceed with surgery the operation will be discussed in detail. This will include any risks or possible complications of the operation and the method of anaesthesia. You will be asked to read and sign a consent form after having the opportunity to ask any questions. You will undergo biometry measurements of your eyes. These involve placing your chin on a rest in front of a special instrument. It is painless and quick. These measurements are used to calculate what power of lens implant to place in the eye at the time of surgery. You will also see a preoperative assessment nurse. She/he will carry out blood tests and an ECG (heart tracing) if required. She/he will also advise you if you need to starve before the operation. If simple local anaesthesia is used you will not need any of these investigations and you will not need to starve prior to surgery.
What should I do about my medication?
Mr McCormick will want to know all the medication that you take and about any allergies you have. In some cases you may be asked to stop or reduce the dose of blood thinning tablets like: warfarin, apixaban, dabigatran, aspirin, clopidogrel (plavix), dipyridamole (persantin). This decision is made on an individual basis and you should only do so if it is safe and you have been instructed by your GP, surgeon or anaesthetist. This will be discussed with you before surgery. Other medication should be taken as usual.
What are the risks and possible complications of surgery?
Infection: This can occur inside they eye after surgery. It presents with pain, redness of the eye and loss of vision. It is very rare – approximately 1 in 1000 cataract operations become infected. If you suspect it has happened after surgery you should contact your surgeon or the hospital urgently. If in doubt you should go to an accident and emergency department. It can cause permanent loss of vision.
Bleeding: This may occur spontaneously inside the eye during or after surgery and cause permanent loss of vision. It can also occur as a complication of local anaesthetic injection causing a penetrating injury of the eye or bleeding around the eye – orbital haemorrhage / haematoma.
Retinal detachment: This rare condition is more common after cataract surgery but the incidence is still very low (1 in 10,000). This risk however does increase significantly if there are other complications, such as needing a vitrectomy at the time of cataract surgery. Also, if you are highly short-sighted you are already at increased risk of retinal detachment and the cataract surgery could add to this risk. Retinal detachment requires surgery by a specialist retinal surgeon in another hospital and can cause permanent loss of vision.
Retinal oedema: Following the operation some people develop fluid swelling in the retina. This can reduce vision. In most cases it is temporary and resolves without treatment. In some however either eye drop medication or injections of medication next to the eye are required. The cure rate is very high.
Corneal failure: The cornea is the clear dome at the front of the eye. The operation takes place inside the eye, underneath the cornea. Mild corneal oedema is not uncommon after surgery. This usually settles spontaneously. In rare cases the cornea does not improve and fails. If this happens, further surgery would be needed to improve the vision.
Loss of vision: The most serious causes of this are bleeding, infection, retinal detachment and fluid swelling in the retina, corneal failure as already discussed.
Incorrect Lens Implant: Despite very careful measurements of your eyes, it is possible for a lens to be implanted into your eye at the time of cataract surgery that does not produce the focus we expected. This is usually mild and correctable with glasses or contact lenses. If it is significant, further surgery to remove and replace the lens implant may be required.
Further surgery: This may take the form of a vitrectomy by your consultant at the same time as your cataract surgery. In which case you may be completely unaware that it has been carried out. The only difference would be a procedure that takes forty minutes instead of twenty.
A more extensive vitrectomy would be required in the rare event of lens matter being dropped into the vitreous jelly of the eye or retinal detachment surgery. In rare cases it is not possible to insert a lens implant on the same day as removal of the cataract. If so, a further operation would be required to complete the process and insert a lens implant. In addition, if the wrong lens has been implanted, further surgery may be required to replace it. Lastly, if the cornea of the eye fails after cataract surgery, corneal graft surgery can be performed at a later date to improve the vision.
Bruising on the surface of the eye or around the eyelids may occur due to the operation or the local anaesthetic. This usually resolves within two weeks.
Allergic reaction to any of the medications used during or after the operation is a rare complication. It resolves with allergy treatment and cessation of the allergenic drug.
Raised eye pressure: Temporarily after surgery the pressure inside the eye may increase. This can be painful but subsides spontaneously in most cases. If pain persists after surgery, you should see an eye specialist without delay.
Benign visual symptoms: After surgery, the improved vision you will experience, may enable you to see imperfections within your eye that were there before but hidden from view. Often described as ‘floaters’ there is no treatment for this but most people find it settles with time.
Some people experience glare or reflections from the edge of the lens implant. This is not common and not treatable but usually settles with time spontaneously
What should I expect after surgery?
After surgery you may experience some pain. Simple paracetamol is usually enough to control this. It is not unusual to experience some mild pain within the first 12 hours after surgery. This usually starts to improve once the eye drops are started.
Your vision will be blurred initially but usually starts to improve within the first 48 hours. If you experience a drop in vision after surgery you should contact the hospital where you had the surgery and speak to a doctor
The legal standard for driving is that you can read a number plate in daylight at 20.5 metres. Also you need to be able to read 6/12 on a Snellen chart (the vision test you have when you see an optometrist or ophthalmologist). As long as you meet these requirements you may return to driving.
You will need to put drops in your eye 4 times a day for a month following surgery. If you don’t think you can do this you should arrange for a friend, relative or carer to do this for you. If you do not have this help a district nurse will need to be arranged.
It is best to wait until both eyes have been operated on before obtaining new spectacles. You should wait at least 4 weeks after surgery before obtaining new spectacles. If only having one eye operated on you may go for glasses after 4 weeks. If having 2 eyes operated on you may see your optometrist/optician in between operations to have the lens removed from the operated eye if your vision is difficult through your old lens
If proceeding to surgery with both eyes, you will be seen in clinic following the first operation. If all has gone well you will then be listed for the second eye surgery.
You may return to normal activities after 48 hours of surgery. You should avoid heavy straining or any form of activity where the eye could receive direct trauma for at least 10 days.
In approximately 1 person in 30, scar tissue grows around the lens implant. This will seem as though the cataract is growing back causing blurring of vision. The cataract cannot grow back and this problem is easily treated with a simple out patient laser treatment. If you think you have this problem, see your optometrist and they will refer you if necessary.
Postoperative Instructions
If an eye pad is placed it should remain until the next morning when you may remove it.
Keep the clear plastic eye shield and wear it every night for the first 10 days
Clean around the eye using boiled water that has cooled down or sterile water sachets. Do this twice a day for 10 days using cotton wool balls.
Put in the post operative eye drops as instructed. Pred-Forte 4 times a day for 4 weeks
Do not allow shower or bath water into the eye for 10 days – you may still bath and shower, just be careful with the eye.
Do not swim in public baths for 10 days
If you are using other eye drops for another problem you should still use them. Please obtain a completely new bottle to use after surgery to avoid infection
If you experience deterioration in vision, pain or redness of the eye you should seek the opinion of an eye doctor without delay, even if out of normal working hours.
