Tears discovery may improve eye care

Tears play a vital function in keeping the eye healthy

Scientists have discovered the unique combination of ingredients that make up tears.

The breakthrough raises the possibility of developing artificial tears that could provide a more effective treatment for people with eye problems across the world.

The researchers, from Oxford University, UK, have patented the combination of proteins and fats.

They hope to use the formula to develop new medicines that will eventually help people who suffer from an inadequate supply of tears.

However, they stress that much work needs to be done before such a product can be made widely available.

Important role

Tears play a vital function in helping to lubricate the eyeball and keep it clear of irritants.

We hope this new approach will stabilise conditions for the eye and help sufferers to live a more normal life

Dr John Tiffany, Oxford University

Tears secrete antibacterial agents that break down harmful bacteria before they can cause infection. They also provide oxygen and nutrients to the cornea, or surface, of the eyeball which has no blood supply.

Without tears, the eye can become dry, red and inflamed. There is also a risk that the cornea will become scarred.

Lack of tears can be a side effect of some medications, such as antihistamines or antidepressants. The condition can also be caused by air pollution.

Tear production also naturally decreases with age. One in five people over 55 experience problems with "dry eyes".

Long process

Drops or ointments currently available for dry eyes contain artificial polymers which can lubricate the eye but do not carry out any of the other essential functions performed by tears.

The discovery of the particular combination of molecules that make up natural tears could result in drops being manufactured that are better able to perform all the functions of natural tears.

Dr John Tiffany, a lecturer in ophthalmological biochemistry, who heads the research group, told the University of Oxford newsletter: "Dry-eye disorders are painful and annoying, and we have no complete cure for them.

"All the available treatments aim to soothe and lubricate the eye in various ways.

"We hope this new approach will stabilise conditions for the eye and help sufferers to live a more normal life."

Milk allergy

However, Dr Tiffany stressed that it would be "some time" before the product was available to the public.

He said: "It will have to be thoroughly tested and that will cost a lot of money. It would be rash to put it straight into production because of the risks."

Dr Tiffany warned that the tears could put people who suffer from milk allergies at risk because they were based on proteins found in cow's milk.

He said: "Anyone without a milk allergy would be fine, but many people don't realise they have one."

The researchers face a problem developing a product which will have a practical shelf life as proteins can easily break down. Extensive safety tests will also need to be carried out.