The eye is a lot like an old style camera with a lens in the front and the film (called the retina) at the back. There are two lenses at the front of the eye. The cornea is the clear outside lens on the front of the eye, in front of the pupil. Behind the pupil is the crystalline lens which provides final fine focus when you are young for reading up close.
Cataract is when the crystalline lens becomes cloudy or foggy.
When your cataract gives you cloudy or foggy vision to the point where it is interfering with your daily life, a cataract procedure may be recommended and once undertaken a successful cataract procedure will never need to be performed again.
The history surrounding the treatment of cataracts is extensive and has come to a point where today we are able to offer a very safe treatment with rapid recovery, called phacoemulsification and intraocular lens insertion.
Cataract Surgery is a day procedure, usually performed under anaesthetic drops and sedation, and on most occasions the patient can go home without a patch over the eye with vision improving rapidly over the next 48-72 hours.
Routine small incision cataract surgery is performed as day surgery and does not involve the use of injections or stitches around the eye. This is because the wound is very small and because the eye can be anaesthetised using drops or gel. A light sedative complements this use of topical anaesthetic.
The phacoemulsification method allows patients to regain vision and resume normal activities very quickly following surgery and is very safe.
This method involves creating a tiny incision on the cornea and removing the natural but clouded lens of the eye and placing an artificial lens where the natural lens was found. Contrary to popular belief this involves the use of ultrasound energy, not a laser.
We currently use the Centurion™ cataract removal system that offers enhanced ultrasound phacoemulsification modalities enabling flexibility in the way the cataract is removed thereby improving safety and rate of recovery.
Small incision cataract surgery
- Does not involve the routine use of injections or stitches around the eye.
- Is usually performed under topical anaesthesia with a light intravenous sedative.
- Takes 10-15 minutes per eye although the total length of your stay at the centre will be approximately 2 hours.
- Generally patches are not required to cover the eye after surgery unless the surgeon advises otherwise. When required it is usually for only a few hours.
- Only one eye is operated on at a time. The second eye may undergo treatment the following week if necessary; usually the most affected eye is treated first. Increasingly, patients elect to have surgery on the second eye the day after the first eye. This reflects the safety and rapid recovery of modern cataract surgery and can have significant advantages. It is vital the first eye be checked before performing surgery on the second eye in these circumstances. The surgeon will advise you on this.
- The rate of recovery varies for each person but, as a general rule, vision improves over a 24 to 72 hour period.
Intraocular lenses implanted during cataract surgery are a fundamental requirement for successful cataract surgery. These lenses are designed to provide the eye with a focal point determined as part of the pre-operative assessment. Most commonly the focus is set for distance but it may also be set for near. Some lenses may also provide more than one focal point to minimise dependency on glasses. Critical to achieving the intended outcome is selecting the correct power and style of intraocular lens. This requires a series of measurements and calculations prior to any surgery.
The equipment for these measurements and calculations is very accurate and the predictability is high but it is not possible to guarantee an outcome for any procedure since some information required for the calculations has to be assumed. In some instances patients may be required to wear thin spectacle lenses after surgery due to residual focusing errors that affects the level of vision without correction. An alternative to glasses in this situation may be surgery, either within the eye to exchange or supplement the intraocular lens used, or by laser vision correction. The risks and benefits of any surgery requires individual assessment, however, the cost of any procedure supplementary is not covered as part of the fee for cataract surgery.
More about Intraocular lenses
Recently, improvements in intraocular lens design have made it possible to provide distance, intermediate, and near vision correction without glasses. There are various combinations of these characteristics with some, but not all patients, being good candidates. Disadvantages include some halos at night and reduced quality of intermediate and near vision.
In general terms there are three classes of intraocular lens:
These are the most commonly used lens as they provide the highest quality of vision. They have a single focal point which is generally set for distance but can be set for near. Usually both eyes are set for distance but in some people one eye is set for distance and the other for near, a term called monovision.
Extended Depth of Focus (EDoF) lenses
These lenses extend the range of focus from distance to approximately 65cms giving good ‘social’ vision. They do not generally give good near vision for detailed reading so reading glasses are still required, but have minimal side effects.
When discussing multifocal implants we really mean trifocal intraocular lenses. These lenses are very different to multifocal glasses.These lenses provide a near focus of 40cm, an intermediate focus from 60-80cm and a distance focal point by splitting the light entering the eye. Whilst they have many good characteristics they can be associated with unwanted side effects that cannot be shown to you before the surgery.
An important consideration with intraocular lenses is the correction of any potential astigmatism that might be expected after the surgery. All lens types have the capacity to correct astigmatism. We use the Verion alignment system from Alcon to maximise the surgical outcomes from astigmatism correcting intraocular lenses.
The intraocular lens best suited to your eye and individual circumstances will be discussed with you as part of your surgical assessment.