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 onto 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 totally removed by laser surgery at the present time. Laser systems for performing several of the initial steps in cataract surgery are now available, however, ultrasound (or phacoemulsification) is still necessary to remove the cataract itself. These laser systems (called femtosecond lasers) have not gained wide acceptance because of lack of evidence for superior outcomes over current techniques, possible increased complications and prohibitive cost. However, a laser (Yag 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 you 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 type of procedure is it?
Almost all cataract surgery is now performed using local anaesthetic. This allows most people to go home on the same afternoon of their surgery, ie. 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. Your anaesthetist will see you prior to surgery to familiarise himself with any medical problems you may have, and ensure all will proceed smoothly. Do not eat for 6 hours prior to surgery. You may have clear fluids only up to 4 hours before surgery (ie. water, black tea or coffee, NO MILK).
How is the anaesthetic administered?
This is given 10 minutes or so before going into the operating theatre by the anaesthetist. There are 2 options available:
- A local anaesthetic “block” of the eye, or
- “Topical” anaesthetic using only local anaesthetic eye drops
The type of anaesthetic will be decided by your anaesthetist and ophthalmologist. 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, surprisingly, 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 your 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. The whole procedure normally takes less than 30 minutes. At the completion, you will be moved to the recovery bay for a short period of observation. You may then have a drink and go home (normally after about 1-2 hours).
How is 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-drive 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 plastic lens, an intraocular lens implant is then inserted into the remaining lens “skin” – the capsule – to replace the natural lens and assist with focusing of light onto the back of the eye. A soft plastic intraocular lens is used which can be folded and “injected” into the eye, enabling this to be achieved through a very small wound of about 2mm wide. No stitches are required as this tiny wound self-seals. The visual result is frequently exceptional with rapid recovery and a return to normal activities within a few days. Often only reading glasses are required after the operation. Your final glasses requirement, however, will be checked by your optometrist once healing is stable, 6 weeks post-operatively.
What are the possible complications?
Fortunately complications are very uncommon but you must be aware of these before consenting to the operation. Serious complications occur in less than 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 in about 1 in every 400 operations. These usually do not significantly affect the final vision result but may delay recovery of good vision. The most frequent problem is rupture of the thin lens capsule resulting in disturbance of the jelly (vitreus) 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.
When will I be seen for follow ups?
Usually you will be seen one to three days after the operation, then 6 weeks after the surgery. A one week follow up visit is sometimes necessary. Please bring your glasses or sunglasses (as protection) and the bag with all its contents, to the first visit after surgery. If you have increasing or severe PAIN, increased REDNESS or eyelid SWELLING, or severe VOMITTING at any time after your surgery, do not wait until your next follow-up appointment, but contact the Clinic on 5470 2400 as soon as possible.
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, again impairing vision. This commonly occurs about 2 years after surgery but can occur at any time. 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 Clinic (Yag Laser Capsulotomy). There is then no chance of any form or cataract returning.
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 to 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.
Are there any questions unanswered?
If you have any further questions, these may be covered in the information sheets and booklet in your Cataract Operation Folder. If not, please ask one of our staff.
Useful Contact Numbers:
Dr John Ambler, Noosa Ophthalmology – 07 5470 2400
Sunshine Coast Anaesthetic Group – 07 5493 4383
Noosa Private Hospital – 07 5413 9100
Kawana Private Hospital – 07 5455 9318