What is a cataract?
A cataract is the last stage of the natural ageing process that affects the lens in the eye. When we are young, the lens is transparent and quite pliable, so it can change shape to help us focus to see things clearly in the distance as well as up close, such as for reading and using mobile phones and tablets.
The Ageing Lens becomes a Cataract
As we get older, the lens becomes less flexible, so although we can still see clearly in the distance, it becomes harder to see things up close. This is called Presbyopia, and reading glasses help to see things close up. Over the years, your reading glasses change to a stronger prescription. The lens is still clear and transparent at this stage. A few years later, the lens starts to become fatter, and changes the vision for distance as well. Many people who never needed glasses or contact lenses for distance such as for driving or watching TV find that they need glasses for distance and near, such as bifocals or varifocals.However, with glasses, the vision is still clear.
Finally, the lens becomes yellowed and opaque and this is when it becomes a cataract. The vision becomes dull and hazy, and glasses do not help as much as they used to. You struggle to see things clearly, especially if the lighting is not bright. Your optician may then advise you to consider cataract surgery to regain clear vision.
Follow this link to watch a short video about cataracts, cataract surgery and aftercare https://youtu.be/UNzz55RARdc
My Hindi/Urdu video about cataracts, cataract surgery and aftercare is here https://youtu.be/XQQv8M3KZEo
What can I expect after cataract surgery?
Vision is usually brighter, crisper and clearer, with better colour perception. In many cases I can select a lens implant that gives you clear distance unaided vision, which means that you won’t need to depend on glasses or contact lenses for distance vision so much. Depending on the outcome you choose, your spectacle/contact lens dependence can be reduced with a lens implant to correct for distance and near vision.
Do I have to have cataract surgery?
You can have cataracts but be managing quite well enough for your needs, and in this scenario you can put off having cataract surgery until things are not so clear.
When your vision becomes dull or hazy, and glasses do not help as much as they used to, you may wish to consider cataract surgery to regain clear vision. You may find your vision is worse if the lighting isn’t very bright, or that seeing things in the far distance, such as bus numbers or road signs, has become harder. You may have difficulty recognising people until they are very close. Night driving may become particularly challenging, and some cataracts can cause quite a lot of glare with oncoming headlights. If you have had a fall or trip recently, it is important your doctors work out why it happened, because poor vision due to cataracts may be a cause.
Questions I usually ask
· Are you having difficulty seeing the TV screen clearly or reading subtitles?
· Are you struggling to recognize bus numbers or people’s faces until they are really close?
· Is it difficult reading small print unless the lighting is really bright?
· Do you feel that your glasses aren’t giving you clear vision, and your optician has said that
they can’t improve with a new prescription?
· Do you have hazy vision?
· Is it difficult to see clearly when you are driving?
· Do you have glare with night driving or in bright lights (such as supermarket lighting)?
· Are you having difficulty reading music?
· Is your vision affecting your work?
· Do have a particular hobby or interest that your vision is affecting?
Even if some of these are affecting one eye you may feel you can manage because the vision is better in the other eye. It is fine to leave cataract surgery and rely on the better eye for as long as you are comfortable with this, unless the cataract is very advanced and you have severe loss of vision – your eye examination will help me to help you make a decision.
You may be advised to have cataract surgery if you have a sight threatening retinal condition but the cataract is interfering with my ability to examine the back of the eye. In this case, I will advise you to consider cataract surgery if I feel that there is a risk of you losing vision if I am unable to monitor or treat the retina adequately.
If you are a driver and your vision does not meet the DVLA standards for driving (read a number plate from 20m, see Driving Eyesight Rules) I will usually recommend cataract surgery if you wish to continue driving. In milder cases you can see your optician first because a change in glasses or contact lenses may improve the vision to legal driving standards for a year or two, but you will need to keep checking to be sure you are legal for driving. You need to be able to read a number plate made after 2001 at 20m in daylight with your glasses or contact lenses if you use them. Your visual acuity must be 6/12 or better and you need an adequate field of vision.
What does cataract surgery involve?
Cataract surgery is a usually done as a day case under local anaesthetic, using either drops or an injection to numb the eye, but if you are particularly anxious about this we can offer sedation or general anaesthesia.
You will have dilating drops for an hour before surgery
You will be lying down on a couch and the operation is done through an operating microscope. A drape covers the other eye so you won’t see what is going on. If you have topical (drops) anaesthesia, you will see a light from the operating microscope which can be a bit bright at the beginning, but the eye gets used to it and soon doesn’t feel too bright. If you have injection anaesthesia, the seeing parts of the eye are also numbed so you do not notice the light so much.
Most patients don’t need any stitches after the surgery, but occasionally I will put in a stitch to secure a wound if it leaks fluid. (Patients who have had previous vitrectomy surgery are more likely to have a fine dissolving stitch in the main wound as an added precaution.)
At the end of the operation you will have a clear plastic shield over the eye, to reduce the risk of you accidentally rubbing it. If you have had an injection to numb the eye and not just eye drops then I will also put a pad on the eye which can be removed the next morning. This is because the injection also numbs the eyelid and you may not be able to close it or blink for a few hours, so the pad protects the eye while the anaesthetic wears off.
Your choices and the conversation we will have about what you want to achieve with cataract surgery.
When you have cataract surgery, the natural crystalline lens that you were born with will be removed and replaced with an artificial lens – an intraocular lens implant, or IOL. The type and power of the lens implant is selected to give you the desired visual outcome. We will talk about visual outcome choices in terms of whether you prefer to use glasses for near or to read unaided, or whether you want to be able to reduce the need for spectacles altogether by having a multifocal lens implant which preserves the ability to focus in the distance as well as near. I have summarised some of the options to consider below.
Single focus intraocular lens implant
- Aim for clear distance vision, use reading glasses for near (both eyes).
- Aim for unaided near vision, with glasses for distance – this is not a common choice for most people, but some people have very specific reasons for wanting this outcome and I am happy to discuss this further.
- This uses standard lenses (relevant for those insured by the few Private Medical Insurance companies who do not cover multifocal or special order lens implants)
- Monovision gives clear distance vision in one eye, and clear near vision in the other eye, and suits some people, who then manage most activities without glasses. For really clear distance vision or detailed near vision you may still need to wear glasses. Many people will have started adjusting contact lenses to achieve monovision, and if you cope with this comfortably it can be reproduced with lens implants.
Toric lens implant for correction of astigmatism
For cataract surgery to achieve the best visual outcomes with reduced spectacle dependence, I recommend toric lens implants when there is more than a certain amount of astigmatism. These require additional tests and calculations before surgery, and special lenses need to be ordered specifically for you. These usually take a few days to arrive so it is important to be prepared to have the tests done on the same day you see me or as soon as possible afterwards wherever possible. Please check that your Private Medical Insurer covers toric lens implants, as not all do. If your insurer doesn’t cover toric lenses you can still have cataract surgery with standard lenses, but may need to continue with glasses or contact lenses to correct astigmatism after surgery. There may also be the option of self-pay for premium lens procedures.
Multifocal lens implant (including toric lens for correction of astigmatism)
- Clearer vision for both distance and near, you may still need glasses for very clear distance or detailed near vision.
- Multifocal lenses are not suitable for everyone
- Side effects of multifocal lenses include glare and halos around lights, which can be troublesome with night driving. Although this is less of a problem with newer lens design, it is still something to be aware of
- Loss of contrast – to achieve the range of distance, intermediate and near vision, there is some loss of contrast. In most cases this is mild and not particularly noticeable in general day to day vision, but if you have specific visual needs then multifocal lenses may not be the best choice for you
- I do not recommend multifocal lenses if you have had previous macular problems, as the quality of central vision may be much poorer with multifocal lens implants than with standard lens implants.
What are the risks of cataract surgery?
I take full precautions to reduce risks, and discuss these with you in advance. However no procedure is without risk, and no surgeon can ever guarantee that you will not have a complication of surgery. The risks are low, and in most cases can be managed well with good visual outcomes. There are certain factors that can increase risk, such as previous vitrectomy surgery, high myopia, small pupils, dense cataracts and many others, which I can identify when I examine you and will discuss with you before surgery.
The risks I discuss are the following:
Infection: this is known as endophthalmitis, a rare infection of the eye. It generally occurs within the first week after surgery, and the things to watch out for are increased pain, redness or blurring of vision in the days following cataract surgery. You should seek prompt advice if you experience these after cataract surgery.
Bleeding: this is less common with modern small incision surgery, but still relevant, particularly in highly myopic (short-sighted) eyes or eyes that have had previous vitrectomy surgery.
Ruptured posterior capsule (the membrane that supports the lens can split during surgery): this is usually managed at the time of surgery, but may mean that a special toric or multifocal lens can’t be implanted.
Dropped nucleus: if the posterior capsule ruptures, pieces of the cataract can fall through into the back of the eye. In most cases a cataract surgeon will need to stop the surgery and refer the patient to a vitreoretinal surgeon such as myself, to remove the pieces of cataract with vitrectomy surgery from the back of the eye. As I am both a cataract surgeon and a vitreoretinal surgeon, I will not need to refer you for surgery on another day, and I would manage the complication myself at the same surgery.
Increased risk of retinal detachment after cataract surgery: the risk of retinal detachment is increased in almost everyone undergoing lens extraction surgery, and is higher in people who are myopic (short-sighted), or who have surgical complications such as a ruptured posterior capsule. Please be aware of symptoms such as new floaters, flashing lights or a shadow or curtain in the vision in the months and years after cataract surgery, as this may indicate vitreoretinal problems.
Macular oedema: this is a swelling at the macula, the central part of the retina responsible for fine vision. It generally occurs some weeks after cataract surgery, with the vision becoming blurred or distorted after a period of clear vision. It is commoner in people with diabetes, even if they do not have any diabetic eye disease. I prescribe drops following surgery to reduce the risk of this swelling.
High or low eye pressure: high pressure is usually temporary and can be treated with eye drops for a few weeks. Low pressure generally settles spontaneously, but occasionally needs a stitch to the surgical wound.
Refractive surprise: although tests are done to predict the right lens implant for the desired visual outcome, these can still, rarely, deliver an unexpected outcome. Usually, the vision adjusts and no further intervention is required. Rarely, the lens implant may need to be exchanged.
Here is a link to some information on the Royal College of Ophthalmologists website Specific Questions Related to Cataract Surgery
You may also find this link helpful Shared Decision Making for Cataracts
Anaesthesia for cataract surgery
Most cataract surgery can be done with just local anaesthetic, using either drops or an injection to numb the eye (you will be awake during surgery).
Some patients are not good candidates for local anaesthesia – either they are unable to lie still for the required time, or they are very nervous or simply have a fear of being awake whilst they have an eye operation. In such situations I can arrange for you to have general anaesthesia as long as your general health can tolerate it – the decision is one that we make with the anaesthetist looking after you to make sure you are safe at all times. I also have the option of offering light sedation instead of full general anaesthesia.
What happens next?
When you make an appointment to see me, I will take a full medical history, and examine both the front and back of your eyes – you will have eye drops to dilate the pupils so that I can examine the lens and the retina, including the optic nerve. This is necessary to make sure that there are no other conditions contributing to your reduced vision.
You will need pre-operative eye measurements called biometry and tests to assess the surface of the cornea called topography, to help predict the lens power to select, and it is usually possible to have these done on the same day. You may need a special order lens implant, which will take a few days to arrive from the time the pre-operative tests are reviewed by me. We can also arrange next day lens delivery if you need surgery in a short space of time. In most cases you can choose which hospital you would like to go to for your surgery, and we can book a date for your operation or my secretary will contact you later to arrange this.
Aftercare following Cataract Surgery
General precautions after all operations
· Use your drops as prescribed. Please do arrange for help with eye drops after your operation if you do not feel you can put them in yourself.
· Cleanse the eye gently with boiled, cooled water.
· Avoid rubbing the eye.
· Do wear the eye shield at night for the first few nights, as it will reduce the risk of accidentally rubbing the eye in your sleep.
· You can be as mobile as you feel comfortable with, but do remember that you have had a big operation and you may feel tired.
· Do not drive in the first few days after surgery as you may not have clear vision with both eyes open and your judgement of distances and your awareness in your peripheral vision may be impaired.
· You may use your vision as much as is comfortable.
When to seek further advice
All operations carry a risk of complications either during or after surgery. One of the most important complications is infection, although the risk is very low at less than 1 in 500. Infections can be treated with prompt antibiotics. Your eye will usually be red and uncomfortable immediately after surgery, and this is to be expected, but you should contact us if you notice any of the following:-
· Increasing pain
· Increasing redness
· Worsening vision