Causes of blindness

Cataract

What is cataract?

Cataract is a clouding of the eye's lens - the part of the eye responsible for focusing light and producing clear, sharp images.

The lens is made up mainly of water and protein. Over time, protein can build up, clouding the light passing through the eye and making sight blurred or fuzzy. For most people, cataracts are a natural result of aging.

Often cataracts develop in both eyes at the same time. The symptoms vary, but include a gradual blurring of vision, halos around lights, glare and double vision. The very worst cataracts - where the iris appears almost entirely clouded over - can cause a total loss of vision.

Causes of cataract

There is no single cause of cataract (the clouding of the eye's lens). A number of risk factors seem to have an impact. There are some risks that can be reduced by a change in lifestyle, and some that can't. Sightsavers is raising awareness of the risks, and providing treatment where possible.

Risks that can be reduced:

• cigarette smoking
• drugs: some eye drops used to treat eye problems contain steroids. If unsupervised and taken over a long time, they can cause cataracts.
• diabetes: proper treatment can reduce the risk of cataract
• dehydration: people who have suffered severe dehydration seem more likely to suffer from cataract. This can result from severe illness (such as cholera), acute heat stroke or even from local customs such as withholding water from women during labour and immediately after giving birth.

Risks that can't be reduced:

• ageing - the single-most important cause of cataract
• genetic predisposition- in 25-50 per cent of cases there is a family history of cataract
• eye conditions such as short sightedness and inflammation in the eye seem to be linked to cataract. Severe trauma to the eye can also be a cause.
• environmental factors - cataract occurs more often and at an earlier age in developing countries
• daylight - some controversially believe ultraviolet light worsens cataract. This is unproven and impossible to combat if true.

Cataracts and poverty

Removing cataract (the clouding of the eye's lens) is a relatively simple surgical procedure. It is common and easily accessible in developed countries. But in the countries where Sightsavers works, many people with cataracts are yet to benefit.

Why is this?

• lack of awareness in some areas about the number of people with cataracts, and how best to diagnose them
• lack of staff and equipment to significantly reduce the growing backlog of cataract operations needed.

There are also reasons why prospective patients may be wary of an operation:

• they may not know that the operation is simple and safe
• they may have heard of someone who had a bad experience while having an operation
• they may live far from towns, and getting to hospital may involve a lot of travel and expense. This is never easy for a blind person.
• as well as the travel costs, people will not be able to work immediately after the operation and will lose income
• people sometimes expect to go blind as a natural part of ageing and are unaware of how simple it is to have their sight restored

Sightsavers is raising awareness of the need for cataract treatment and providing it wherever possible.

Our work with cataract

Our cataract work involves a number of different aspects:

Screening and referring those in need

We train local community health workers to identify those in need of cataract treatment, ensuring that they are referred to an ophthalmic specialist for an operation.

Providing free surgery and transport

The only way to treat cataract (the clouding of the eye's lens) is by surgery. This involves removing the cloudy lens, leaving the capsule that contains it intact. A plastic lens is inserted, meaning that there is no need to wear special glasses after the operation.

Many people live a long way from hospitals or clinics, so wherever possible we provide transport so they can get to where their treatment is being carried out.

We also carry out surgical outreach camps in areas that are difficult to access, or there is a poor or ineffective health system in place.

Training new eye-care personnel

We are tackling the growing number of people needing cataract treatment by training ophthalmic staff. Experienced ophthalmic nurses are trained to undertake cataract surgery, as well as to manage eye care services and train and supervise new eye-care workers. Ophthalmic nurses play a key role in preparing patients for surgery, freeing the surgeon to carry out the eye operation itself.

Improving the standard of service

Sightsavers believes it is important to ensure that the experience of treatment is positive. If the experience is good, patients will return to their village and tell people about it, making others with cataract willing to undergo similar operations.