Simon G Levy

Consultant Eye Surgeon
Reassuring Personal Care - Advanced Technology - Specialist Cataract and Refractive surgeon

What is cataract?

Cataract is a clouding of the lens of the eye. As the lens is no longer transparent, light cannot pass through it to reach the retina and vision deteriorates. In most people cataract is simply an aspect of ageing and not related to any other eye or body disorder.

In a normal eye (left) images are focused onto the retina. Photo of transparent normal lens (right)

In an eye with cataract (left) images cannot reach the retina. Photo of cloudy cataract lens (right)


Cataract causes gradual deterioration of vision, objects becoming less and less clear until eventually all sight is lost. Often more light than before is needed to see and to read. Colours may seem muted or yellow and there may be glare on a sunny day or when driving at night. Another symptom is increasing short sight, necessitating frequent changes in the glasses prescription. Cataract is usually present in both eyes although it may be more advanced in one eye.

Blurred vision caused by cataract (left) is cured by surgery (right)

Colours are less rich before (left) than after (right) cataract removal
(images are simulated)

The benefits of modern cataract surgery

Depending on the symptoms caused by your cataract, you may enjoy some or all of these benefits from surgery -

  • Improved clarity of vision
  • Improved vision in dim light
  • Reduced glare on a sunny day or during night driving
  • Colours are richer
  • Improved vision may enable you to continue driving
  • Many studies have shown improved quality of life after cataract surgery. Activities such as reading, sports, cooking, driving and using a computer are generally easier after the operation. Even when the eye also suffers from other problems such as retinal disease, the remaining vision is usually improved by cataract surgery
  • The need to wear distance glasses may be less after cataract surgery. Some patients also become less dependent on reading glasses. This is so even when glasses have been necessary for many years
  • The phaco-emulsification technique is usually quick, safe and gentle to the eye and the recovery period is very short so that these improvements can be enjoyed quickly

When to have cataract surgery

Cataract is best treated as soon as it is interfering significantly with your life. Delay is inappropriate as cataract gets worse with time and surgery is easiest when undertaken early. The sooner it is done, the longer you will enjoy its benefits - with modern technology waiting for a cataract to ‘mature’ or ‘ripen’ is outmoded.

How cataract surgery is performed

Cataract surgery is performed by a key-hole technology unique to the eye, called phaco-emulsification. This is one of the best procedures of modern medicine. It is quick, taking only 15-20 minutes in most cases and has an outstanding safety record. The small incision is gentle to the eye and heals quickly without stitches. Recovery is so fast that most normal activities may be resumed the day after the operation.

1) Phaco-emulsification

An operating microscope designed specifically for eye surgery and delicate, miniaturised instruments are used. A keyhole incision about 2mm wide is made on the outside of the eye. The lens capsule is then opened to expose the cataract. Next the phaco-emulsifier is inserted. This sophisticated instrument uses ultrasound to break the cataract into tiny pieces which are then suctioned out of the eye.

2) A lens implant

Removing the cloudy lens is necessary to allow light to pass to the retina. However to fully restore vision the focusing power of the lens must be replaced. A lens implant is a very small focusing lens made of clear, medical-grade plastic.

3) The lens implant is injected

This is achieved by putting an artificial lens, called a lens implant, into the space inside the lens capsule created by removing the cataract.

4) The lens implant in place

Once implanted it will remain permanently inside the eye, requires no care and will not be rejected by the body.