New treatment to prevent blindness used at St Thomas'

A pioneering device which helps fluid to drain from the eye is being used in a trial at St Thomas’ Hospital in the hope that it will save patients’ sight.

Surgeons at the hospital are using the special blade to treat patients with glaucoma, a common age-related condition which can lead to blindness and affects around half a million people in England.

The new procedure uses a device known as the Kahook dual blade (KBD) which works by removing tissue that has become blocked along the eye's drainage system, the trabecular meshwork. As a result, more fluid is expected to reach the channels of the drain and leave the eye, which should reduce pressure within it.

Glaucoma usually occurs when fluid in the eye cannot drain properly and increases pressure inside the eye, putting pressure on the optic nerve, which is responsible for sight.

The device is being trialled as part of a small clinical study at St Thomas’ which uses special equipment, known as a Schiotz tonographer, to measure how much fluid drains from the eye before and after the procedure. The equipment is only available in a few centres in the world and has been developed by Mr Sheng Lim, consultant ophthalmic surgeon at St Thomas’.

Mr Saurabh Goyal, consultant ophthalmic surgeon at St Thomas’, is leading the trial with Mr Lim. He said: “It is early days but the new blade appears to be an exciting development in the treatment of glaucoma. The condition causes irreversible blindness so it’s vital to treat it early and prevent any further damage.

“Traditional glaucoma surgery involves creating a hole in the eye to drain the fluid, whereas the new treatment utilises the natural drains of the eye. This has advantages because there is less risk of infection, bleeding, loss of sight and the pressure in the eye falling too low than with the conventional surgery. The KDB procedure is carried out under local anaesthetic and has a faster recovery time than the traditional operation.

“Unlike conventional surgery, the new procedure can be combined with cataract surgery. It is beneficial to treat the two conditions at once because 10 per cent of older people have them both.

“Other treatments including laser surgery and eye drops to reduce the pressure in the eye do not always work and eye drops can have side-effects. We hope that the KDB procedure will become an effective alternative for patients although more research is needed to assess the longer-term effects of the device. As part of the trial we will follow up patients for six months after the procedure which should provide this insight.”

The first patient to join the trial was Asteroulla Antoniou, a 76-year-old grandmother, who was diagnosed with glaucoma around 25 years ago.

Over the years she tried eye drops and laser surgery but they did not reduce the pressure in her eyes enough and she had an allergic reaction to some of the drops.

Asteroulla, from Streatham in south-west London, said: “My father went blind as a result of glaucoma so I was worried that would happen to me too. My vision has deteriorated a bit already and I didn’t want it to get worse.”

She had the KDB procedure on her left eye in January and a few weeks later tests showed that the pressure in her eye had halved and three times as much fluid was draining from it. She does not need to use glaucoma drops for this eye now.

Asteroulla added: “It was unbelievable when Mr Goyal showed me how much fluid had drained from my eye – it was really something to see! Soon I’ll have it done in my right eye too and hopefully I’ll be able to stop using the drops completely.”