A third of patients with a common eye disorder do not take their medication properly, running the risk of losing their sight.

A survey of patients with glaucoma found many experience problems using multiple eye drops, which need to be taken several times a day.

Experts from the International Glaucoma Association (IGA) say the new kinds of drops which combine drugs would simplify managing the condition for patients.

They add eye specialists need to ensure patients understand that if they do not continue to use the drops as prescribed, they could risk their sight.

Communication and education are the keys to successfully managing glaucoma

Professor Roger Hitchings, European Glaucoma Society

Improving the long-term management of the disease could help hundreds of thousands of patients, they say.

Glaucoma is a complex group of eye disorders which all involve damage to the optic nerve.

If untreated, it can lead to loss of vision due to increased pressure inside the eye.

Failing to wait

The IGA surveyed 243 patients using more than one eye drop treatment for their glaucoma, and 250 doctors from France, Germany, Italy and Spain.

A third of patients had missed taking their medication during the previous month.

The survey also found patients did not wait long enough between putting different types of drops in their eyes, which can also affect how effective the treatment is.

Although the advice is to wait between five and 10 minutes, 17% waited two minutes or less between doses.

The majority of eye specialists, 93%, say at least some of their patients do not follow instructions regarding treatment satisfactorily.

Nine out of 10 say a once-daily combined treatment would vastly improve compliance, compared to traditional treatments where patients must take a number of drops two to three times a day.

Three-quarters of patients also backed simpler treatments.

Combination medicines

David Wright, chief executive of the IGA told BBC News Online: "There's the problem of understanding what the benefits of the treatment are.

"It's something that stings and makes vision a little bit blurred - and you can't see the benefits.

"That's not an awful lot of incentive to carry on using it, unless doctors properly explain what the benefits are."

He added: "Effective fixed combination medications would also enhance convenience, particularly for patients who have difficulty taking multiple medications."

Professor Roger Hitchings, president of the European Glaucoma Society, said: "Communication and education are the keys to successfully managing glaucoma and, together with effective treatment options, can help improve compliance and vision outcomes."