What is a cataract?
A cataract is any clouding of the lens of the eye. The lens is situated inside the eye, behind the pupil. It acts in the same way as the lens in a camera to help focus light rays on to the light sensitive nervous tissue in the back of the eye – the retina.
While it is common to refer to cataracts as “growing”, there is little change in the size of the lens. The lens simply becomes increasingly cloudy changing to a brown colour and slowly impairing vision. A frequent misconception is that a cataract is a growth across the surface of the eye.
The ancient Greek physicians knew of cataracts and referred to them as hypochyma. The Arabs translated this as “downpour of water” and this was later transcribed into Latin as cataracta or cataract. Cataract also means a large sheer waterfall and vision in cataract affected individuals was often described as like looking through a waterfall.
What are the symptoms of a cataract?
Other than gradual misting of vision, other effects include glare in bright light, double vision in one eye and frequent changes in glasses prescriptions. Occasionally the clouding within the lens occurs (or becomes noticed) over a short period of time with fairly rapid loss of vision. If left, eventually the lens of the eye becomes totally white and the eye blind.
What causes a cataract?
The exact cause of cataracts is not known. Most commonly cataracts occur as part of the normal ageing process. Sunlight exposure, smoking and family tendency may contribute. Some special forms of cataract are known, including those in newborn babies, following eye injury, and due to certain drugs such as steroids.
How are cataracts treated?
At the present time the only treatment is surgery – an operation to remove the cloudy lens of the eye.
Can cataracts be removed with laser?
No. Cataracts cannot be reliably removed by laser surgery at the present time. Laser systems for cataract removal have been trialled in the past and found to be inefficient, and have now largely been abandoned. However, a laser can be used to treat “after cataracts” as described later in this booklet.
When is my cataract ready to be operated?
This is a decision to be made between you and your eye surgeon. Generally once your vision is impaired to the point where it is interfering with your daily activities or pastimes, it is worth considering having surgery. You do not have to go completely blind or “wait for it to grow right over the eye”.
Am I too old for cataract surgery?
Everyone wishes to enjoy the benefits of the best possible vision in their later years and carry on a normal active lifestyle. Fortunately age is not a barrier to cataract surgery. Even people up to 100 years old have had surgery with great benefit. There are also few, if any, medical conditions that prevent surgery.
What are the possible complications?
Fortunately complications are very uncommon, but you must be aware of these before consenting cataract surgery.
Serious complications occur in less that 2 in every 1000 operations. These include sudden bleeding in the back of the eye, infection or detachment of the retina. These problems can happen days, weeks or months after the surgery and may result in a significant loss of vision.
Less serious problems occur about 1 in every 400 operations. These usually do not significantly affect the final visual result, but may delay recovery of good vision. The most frequent problem is rupture of the thin lens capsule resulting in disturbance to the jelly (vitreous) within the eye. This may require a different sort of intraocular lens to be inserted. On rare occasions fragments of the hard nucleus may sink into the jelly when the capsule ruptures and may even need a further operation a few days later for removal.
Sometimes there is a slight droop in the eyelid immediately after surgery due to the local anaesthetic injection. This almost always recovers spontaneously after a few weeks or months.
But don’t worry, overall cataract surgery is one of the most successful of all operations, with 95% or more of patients obtaining a marked improvement in vision.
What happens during the procedure?
Almost all cataract surgery is now performed using local anaesthetic. This allows most people to go home on the same afternoon of their surgery i.e. day surgery. Some patients, however, due to certain medical conditions may need to stay overnight. After admission to hospital, and about 1 hour before surgery, a series of drops will be placed in the eye to enlarge (“dilate”) the pupil to facilitate surgery.
The anaesthetist will see you prior to surgery to familiarise himself with any medical problems you may have, and ensure all will proceed smoothly.
How is the anaesthetic administered?
This is given 10 minutes or so before going in to the operating theatre by the anaesthetist.
There are 2 options available:
1. A local anaesthetic “block” of the eye, or
2. “Topical” anaesthetic using only local anaesthetic eye drops
The type of anaesthetic will be decided by your anaesthetist and eye doctor.
In both cases a small needle will be placed in a vein in the back of your hand and a mild sedating drug injected to relax you. If topical anaesthetic only is to be used, a series of local anaesthetic drops will then be placed in the eye prior to entering the operating theatre. If an eye block is employed, a fine needle is passed into the eye socket below the eye and local anaesthetic is injected. This is quite painless. Occasionally more anaesthetic is injected into the skin around the eye to paralyse the eyelids.
What happens in the operating theatre?
You will be carefully positioned on the operating table and made as comfortable as possible by the anaesthetist and the theatre staff.
An iodine based antiseptic solution is applied around the eye and a paper drape placed over the face. Fresh air will be blown in through a small face mask positioned near your mouth. A microscope will be positioned above. This will appear as a very bright light just as the operation is commenced. You should try and stay as still as possible while remaining relaxed. You can speak to us if you need to let us know of any discomfort or problems you have. Background music will usually be played and you will hear the voices of the theatre staff.
How is the surgery done?
The cataract is removed by a technique called phacoemulsification or “phaco”. This method removes all but the thin skin-like covering of the lens, the capsule. The hard central “nucleus” of the lens must be removed first, and this is achieved with the use of a rapidly vibrating, ultrasound-driven probe, which breaks up the nucleus and sucks it out of the eye. Residual soft lens material is then also vacuumed out. This is now possible through a very small wound in the eye.
The process can be likened to removing the hard nut (nucleus) and then soft flesh of an avocado, while leaving most of the skin intact. You may hear the high pitched humming noise of the machinery used during this process.
A tiny soft plastic lens, an intraocular lens implant or IOL, is then inserted into the remaining lens “skin” – the capsule – to replace the natural lens and assist with focusing of light on to the back of the eye. Today’s IOLs are folded and “injected” into the eye through a very small wound of only about 2mm wide. No stitches are required as this tiny wound self-seals, dramatically shortening the recovery period.
The whole procedure normally takes less than 30 minutes.
What happens after surgery?
When your eye surgery is finished your eye will be protected by a plastic shield. You will be moved to the recovery bay for a short period of observation and given something light to eat and drink. The nursing staff will explain how to look after yourself in the post-operative period. You will be given a bag containing a cleansing pack and your post-operative eye drops, along with written instructions for their use. Most patients are able to leave the hospital within 2 hours of their surgery. As you will have had an anaesthetic, it is essential that you arrange for an adult to collect you and stay with you for 24 hours following your surgery.
When will I be seen for follow ups?
Usually you will be seen by your eye specialist one or two days after the operation, then 1 week later, and then a further 5 weeks after that (ie 6 weeks after the surgery). You will be asked to bring your glasses or sunglasses (as protection) and the bag with your eye drops and cleansing pack, to your post-operative check-ups.
What can I expect during the recovery period?
During the day it is important that you protect your eyes. You may wear either your prescribed distance glasses or non-prescription sunglasses. You do not need glasses or sunglasses when indoors. To protect your eye at night it is advisable to wear your eye shield for the first few nights after surgery.
It is very important that you take your eye drops as prescribed. Please avoid bending down or strenuous activity to avoid pressure on the eye. You can read and watch television but do not drive for at least 24 hours after your procedure. If you have increasing or severe pain, increased redness or eyelid swelling, or severe vomiting at any time after your surgery, please contact the Clinic on 5492-2822 as soon as possible.
Initially your vision may be blurry, but the visual result is frequently exceptional with rapid visual recovery and a return to normal activities within a few days. Colours will appear brighter and often only reading glasses are required after the operation. Your final glasses requirement will be checked once healing is stable, 6 weeks post-operatively.
Can cataracts develop again?
No, but the thin skin (capsule) surrounding the lens of the eye, which is left behind to help support the implanted intraocular lens, may gradually go cloudy months or years after the operation, again impairing vision. This is sometimes called an “after-cataract” although it is not a true cataract. It is a simple matter to treat these using a laser in the office (a YAG laser capsulotomy). There is then no chance of any form of cataract recurring.
How long will my intraocular lens last?
Plastic lenses have been inserted into eyes for over 50 years. Earlier models caused problems due to poor surface finish and movement within the eye. Today’s intraocular lenses are made to exceedingly strict requirements with superb surface finish inciting little or no reaction in the eye. Surgical advances mean that the implant can be placed consistently into the eye in a stable position where there is very little possibility of movement or contact with surrounding structures. The intraocular implant is manufactured from an inert soft acrylic material which will not breakdown in the eye and should be capable of safely lasting a lifetime.