Learn About Eye Care
A cataract occurs when the clear lens inside the eye becomes cloudy. In its early stages it may not affect your vision although you might notice that oncoming headlights are a bit more dazzling or that you need a better light when you read.
The only proven treatment for a cataract is surgery and only becomes necessary if the cataract gets to the stage where it affects your sight too much for you to see well enough. Drivers may need to have cataract surgery sooner than non-drivers as they need to meet the DVLA vision standard but you are unlikely to have a cataract removed unless you actually want to do so.
Why do cataracts occur?
The main cause is age. However, smoking and exposure to sunlight have also been linked to cataract formation. Some medical conditions - especially diabetes - can cause cataract development as can some drugs. They can also be caused by injury. A very small number of babies are born with a cataract in one or both eyes.
Can cataracts be prevented?
There is no scientific evidence to show that any supplements or eyedrops can prevent or treat cataract. The best advice is to not smoke and to wear good quality sunglasses with full UV protection.
What are the common symptoms of cataracts?
For most people, the main complaint is some deterioration in the quality of vision. In the early stages, you might need your glasses updating more frequently as the prescription can change quite drastically. Some long-sighted people find that they need to wear their glasses less often.
Over time, new lenses may not make a difference. You will be more aware of glare and dazzle from bright lights or when the sun is low in the sky. You may experience problems moving from shade to sunlit areas or when moving indoors from outside. Sometimes, people can complain of a 'shadow' behind objects they are looking at. Colours may look different too and becomae faded or yellowed.
If you experience any of these symptoms, make an appointment to see your optometrist.
Because cataracts normally develp very slowly, over many years, most people don't notice the gradual detrioration in their vision until it starts to interfere with daily activity or it is mentioned by their optometrist during a sight test.
How Are Cataracts Treated?
The most effective treatment for cataracts is an operation to remove the cataract, and replace the cloudy lens with a clear artificial lens implant.
The lens of each eye should be clear in order for your eyes to work properly. The clear lens allows light to reach the retina at the back of the eye, which enables you to see things. With a cataract, less light can reach the retina, so your vision is affected. A cataract can be present for a while before you notice you have one. If you have a cataract, it will continue to develop. When spectacles can no longer improve your vision, the only way to restore your vision is by having the cataract removed by surgery.
The cataract operation
Cataract surgery is one of the most common and quickest surgeries performed today. Modern cataract surgery (called phacoemulsification) is usually performed under local anaesthetic as a day case procedure. During the surgery, a tiny incision is made into the eye and the lens removed with an ultra-sound probe. The capsule of the lens is left behind and this is used to house the new lens implant. The whole procedure takes between 15 and 20 minutes and the visual recovery is very quick with most patients noticing improved vision within a matter of days.
Lens Implant Types
Each patient and each eye is different. Measurements are taken prior to surgery (called biometry) to establish the correct lens power for the individual eye. Lens implants also come in different types. The two major categories of lens implant are:
Monofocal lenses (the vast majority of patients have this lens type put in)
- These provide good distance vision but glasses are required for close work.
- These lenses offer a high probability of achieving spectacle independence i.e. providing patients with the ability to see far as well as to read without glasses.
Multifocal lenses have been shown to offer a high chance of reducing dependence on glasses for near and middle distance vision. However, patients can experience a reduction in contrast sensitivity (especially in dim lighting), as well as halos and glare around lights at night. Some patients are prepared to accept these visual effects because they are very keen to reduce their reliance on glasses.
The pre-operative preparations for patients interested in multifocal lens implants are more involved than when monofocal lenses are being used, a wider range of issues needs to be discussed and the post-operative management is more intensive. These are the major reasons that these lenses are not offered on the NHS.
Risks of cataract surgery
As with any surgical procedure, there are risks involved. However, the chance of a significant complication which could have an impact on your vision is very rare.
Article produced with assistance from Mr A Mearza - FRCOphth. Consultant Ophthalmologist, Imperial College NHS Trust, London.