How tiny implant lets eye patients ditch the drops

ATINY biodegradable implant that slowly dispenses drugs could help thousands of glaucoma patients ditch their eye drops.

Barely bigger than a grain of sand, the rod- shaped pellet is inserted into the eye in a quick, painless procedure lasting just two minutes. It begins to dissolve, releasing vital medication for up to a year until it disappears entirely.

Eye drops are often one of the first treatments tried by patients with glaucoma, which affects some 600,000 people in the UK and almost 80 million worldwide.

The condition occurs when the optic nerve, which is located at the back of the eye and connects it to the brain, becomes damaged.

This is often because water in the eye’s anterior chamber, in front of the coloured iris, isn’t draining properly. Fluid builds up, putting pressure on the eye and causing damage. If this is left untreated, it can lead to tunnel vision and even total blindness.

Eye drops may be used to lower pressure in the eye, but some people need to use them several times a day to manage the condition. This can be a nuisance – or nearly impossible for those with mobility issues such as arthritis. It is estimated that 80 per cent of people do not use the drops as instructed, either forgetting or missing doses. This raises the risk of vision loss.

Research suggests the Bimatoprost SR implant treatment is just as effective as regular drops, and it is being trialled at NHS hospitals as part of an international study.

Dr Andrew Tatham is a consultant ophthalmologist at the Princess Alexandra Eye Pavilion in Edinburgh, one of the hospitals taking part. He says: ‘There are potentially millions of people around the world who could benefit from this drop-free treatment.

‘This is probably just the start. The implant lasts for a year, but in the future we could have one that lasts for five years.’

As well as struggling to use their eye drops regularly, some patients experience side effects such as red and dry eyes.

The new implant contains the same medication as in some regular drops – bimatoprost – but not the preservatives that can cause irritation, says Dr Tatham.

Made of a biodegradable material known as polymer matrix, the pellet delivers the drug directly where it is needed in the eye, so only very low doses are required. When the pellet has completely dissolved, t he patient can have another implant and repeat the treatment.

It takes just minutes to have one put in place. First, a few numbing drops are applied to the eye. A medical tool called a speculum is used to hold the eyelids apart, and the eyeball is held still with another instrument.

Next, a sharp- t i pped device resembling a pen is inserted into the front chamber of the eye through the transparent cornea. At the press of a button, the slowrelease drug pellet is inserted. It then floats down to the bottom of the chamber, where it remains.

Finally, the patient is given a one-off antibiotic eye drop to keep infection at bay.

Dr Tatham says: ‘It’s completely painless and people can even drive home. The recovery is very, very quick.’

If necessary, the implant can be removed from the eye with the help of a specialist.

The latest trial of Bimatoprost SR, t aki ng pl ace i n NHS hospitals i ncluding Moorfields in London and Addenbrooke’s in Cambridge, i s comparing t he implant with another effective glaucoma treatment called selective laser trabeculoplasty.

In an appointment lasting about 15 minutes, this uses some 100 tiny laser pulses to improve drainage in the eye.

Alison Farmer, 70, who lives in the Shetland Islands, is one of the first patients to benefit from the Bimatoprost SR procedure.

Her glaucoma was diagnosed following a routine eye test in October last year, and in January she signed up to take part in the trial after being told about it by her consultant.

‘While waiting for the operation, I went on the normal eye drops that people have,’ says Alison.

‘Having to remember to do them every day was a pain. I used to put them in during the early evening, which was fine when I was at home. But sometimes, I’d suddenly remember later on when I was out that I hadn’t done them.’

In April, Alison had the implant fitted in one eye and the other treated with the laser.

To ensure accurate results, she has not been told which eye has had which treatment – but so far, both appear to be responding equally well.

‘It’s excellent. I can just get on with life, without worrying about drops,’ says Alison. ‘I would definitely recommend it.’