What is a cataract?
A cataract is a clouding of the natural clear lens of the eye. As we get older, the natural lens continues to grow and gradually becomes cloudier resulting in reduction of vision. Other causes of cataract include medical conditions such as diabetes, medications and trauma.
The word “cataract” comes from the Greek word “Cataracti” which means waterfall. The lens can take on this appearance when the cataract is quite advanced.
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. The only way to restore your vision is by having the cataract removed by surgery.
Lens with cataract
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 incison 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 with cataract
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 incison 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.
• Multifocal lenses
- 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.
