Could eye drops replace cataract surgery?

Eye drops could be available in five to seven years and are expected to be much cheaper than surgery. Photo / Thinkstock

Cheap eye drops could soon be available for cataract patients, doing away with the need for costly surgery.

Doctors have found a chemical that dissolves cataracts, which cause blindness if left untreated.

The easy-to-administer drops, which would be used twice a day, could be widely available in five years. In tests, they have been shown to break up the clumps of protein that cloud the vision of more than half of pensioners.

Currently the only treatment is an operation. However, although it is a quick and relatively minor procedure, it is not without complications.

The cash-strapped NHS is rationing the surgery - in some parts of the country patients have been told their vision is still "too good" for treatment, even though their cataracts are so severe they cannot drive or read. Others have been told only one eye will be operated on.

A cheap but effective drug in eye-drop form could mean more patients get the treatment they need. And if given early enough, it might even prevent cataracts developing in the first place.

Cataracts occur when proteins in the eye's lens clump together, turning it cloudy and stopping light from passing through the eyeball to the retina. Sight becomes blurred and colours appear washed out. If the condition is left untreated, all vision is lost, with cataracts causing more blindness worldwide than any other eye condition.

US researchers have shown the chemical lanosterol, which is naturally present in healthy eyes, can break up clumps that cloud the lens. They tested lanosterol eye drops on elderly dogs and rabbits, the journal Nature reports.

Eye specialist Dr Kang Zhang, from the University of California, San Diego, hopes to start the first clinical trials on humans in the next one to two years.

Dr Zhang came up the idea for the eye drops after treating two young children with cataracts.

When he examined their DNA, he found they carried a mutation that stopped their bodies from making lanosterol. It is thought that when we are young, the lanosterol we make copes with any clumping that occurs. But as we age, the amount of clumping increases and we do not produce enough lanosterol to deal with it - so cataracts develop. Dr Zhang says that as lanosterol occurs naturally in the human eye, it should be safe for use as a drug.

Eye drops could be available in five to seven years and are expected to be much cheaper than surgery. The chemical may even hold promise for developing treatments for other illnesses characterised by the clumping of proteins, including Alzheimer's.

Clara Eaglen, of the Royal National Institute of Blind People, said: "This is an exciting scientific development and has expanded our knowledge of how cataracts develop. Anything that removes the need for invasive surgery will be hugely beneficial to patients. If eye drops could be self-administered, this would remove the burden on eye clinics. Of course ... extensive trials are required to establish whether lanosterol can be used safely and effectively."

- Daily Mail