Tap in the eye that could stop glaucoma patients losing their sight
GLAUCOMA affects around 300,000 people in the UK and is a leading cause of blindness. Retired nurse Bernie Pedley, 73, a grandmother from Freckleton, near Preston, Lancashire, was the first to be given a new implant for it, as she tells ADRIAN MONTI. THE PATIENT
DURING a routine annual eye test when I was 58, the optician spotted that the pressure in both my eyes was much higher than it should have been, potentially a sign of glaucoma — where the fluid in your eye builds up, damaging your optic nerve.
I had worn glasses for short-sightedness since I was a toddler and I’d had regular appointments with opticians all my life, which were always pretty routine, so this was a bit of a shock.
I hadn’t noticed any symptoms, but apparently it’s your peripheral vision that’s affected first. My optician said to come back in 12 months.
By then, the pressure hadn’t reduced, so although my sight wasn’t any worse, I was referred to hospital and given daily eye drops to reduce the pressure.
But these gradually became less effective so, in 2008, I had an operation to remove part of the drainage tubes from my left eye, which was my worst — apparently this helps the fluid flow away more easily.
This was done under local anaes-thetic and was unpleasant because I had to keep my eye wide open. Even worse — it didn’t work.
I continued taking the drops for the next eight years and then, when I went for my check-up in 2016, they found that the pressure in my left eye was twice as high as it should be. It was a case of panic stations as there was a real danger I could go blind, so I had emergency laser surgery that day to burn through the tissue to help improve the drainage.
Again, I had this done under local anaesthetic — a horrific experience — and it didn’t work. I was then referred to Manchester Royal Eye Hospital, where I had checks every two or three weeks for a year.
At this point, I was going every-where with my husband Peter as I’d lost confidence doing anything on my own outside the house.
But in May this year, my consult-ant ophthalmic surgeon Leon Au said I’d be an ideal candidate for a new implant because I had advanced glaucoma and I’d had surgery that hadn’t worked.
Mr Au explained he would fit a drainage tube into my eye that could be adjusted like a tap, using a magnet. I would be the first in the country to have it.
I felt excited rather than nervous — I had nothing to lose. My glau-coma was getting worse and would eventually make me go blind.
I had the surgery in early June (although I was given the option of a local anaesthetic, I decided to be put to sleep). When the dressing was removed the next day, my eyeball looked very bloody and was sore, but this passed after about seven days.
A week later, I saw Mr Au, who used the magnet to open up the device further. When I saw him two weeks later, he opened it further still and said my eye pressure was now normal.
I didn’t notice my sight changing at all, but I’m relieved I’m not now in danger of going blind — and proud they tried the technique on me first.
THE SURGEON
Leon Au is a consultant ophthalmic surgeon at the Manchester Royal eye Hospital. GLAUCOMA is associated with high pressure caused by a build-up of fluid that damages the optic nerve. It’s unclear why in some people this fluid build-up occurs.
An estimated 50 per cent of people in the UK with glaucoma are undiagnosed as the symptoms are not always obvious at first — it’s normally only picked up during regular eye checks (which is why you need them after the age of 40, or earlier if there’s a family history of glaucoma).
The first-line treatment is eye drops, which make the eye produce less aqueous humour, the watery fluid in the eye. We don’t believe those with glaucoma actually make more fluid, but simply that their drainage channels are not as effective as they should be.
If the drops don’t work, we usually move on to surgical options. Often this can be laser surgery to improve the drainage channels — the trabecular meshwork — by making it more permeable to fluid.
It typically shows some improve-ment in 75 per cent of patients, but often the effects last only three or four years as the meshwork gets clogged up again.
If laser surgery doesn’t help, we drain the fluid with trabeculectomy — one of the most effective ways to treat glaucoma, it’s been around for about 50 years.
We create a small flap on the top of the eyeball with a drainage hole underneath. We use stitches in this flap to alter how quickly the fluid drains through this hole. It’s generally successful, but in some patients it fails because the body naturally wants to heal itself.
In advanced glaucoma, we’ve been inserting a tiny plastic tube into the hole. But although this is good at lowering the pressure, there’s an increased risk of complications as it’s a case of ‘one size fits all’. In some patients, it doesn’t drain away enough fluid. In others, too much flows away, causing the pressure in the eye to fall too low and sight can be lost, possibly within a few days.
We’ve tried putting stitches around the tube or placing things down it to make the draining less efficient, but it’s always been a case of ‘we could do better’.
Then, eye Watch came along — one of the more exciting potential advances, although we’re currently using it only as part of an 18-month clinical trial.
It’s aimed at patients with advanced glaucoma where surgery has failed. In the past, we have had nothing new to offer this large group of patients.
The eye Watch was designed in Switzerland and is an intricate mechanism — like a wind- up watch — inside a plastic casing that’s attached to a drainage tube. It can be adjusted to one of six settings to reduce or increase the flow of fluid; this is all done with a magnet fitted to a pen- sized device that the surgeon holds 2mm away from the eyeball.
The magnet rotates a metal disc inside the casing which compresses or releases the drainage tube.
First, we make a narrow, needle-width hole in the front of the eye- ball underneath the upper eyelid. The tiny plastic drainage tube goes into this — it’s then attached to the eye Watch mechanism, which is about 4mm wide and is anchored to the surface of the white of the eye.
Then, a donor piece of sclera, the fibrous outer layer of the eye, is stitched over it. A plastic tube is attached to the back of the eye-Watch, to drain to the back of the eye socket. Everything is hidden by the top eyelid.
Once the surgery is completed, I set the eye Watch to a minimum flow. The patient stops taking their eye drops, so the pressure starts to build, and over the next two or three weeks I use the magnet to alter the setting. This device is the closest we have to installing a ‘tap’ in the eye.
It’s still in clinical trials in Switzerland and Greece as well as here in Manchester — we’ve fitted three implants so far and a further trial is about to start at St Thomas’ Hospital in London.
The concept appears to be a game- changer, but we’ll know more once the trial is completed.