Why does your sight get worse with age?

AN ESTIMATED five million Britons are living with age-related eye conditions, such as glaucoma. We spoke to the experts to discover the latest on prevention and treatment for four common problems.

GLAUCOMA

This is caused by fluid building up in the eye as the drainage tubes become blocked — typically because of age. This puts pressure on the optic nerve.

it starts with blind spots at the edge of your vision that you won’t notice, progressing to tunnel vision and sight loss, which can take up to five or six years to become apparent, says Gus Gazzard, a consultant ophthalmic surgeon at Moorfields Eye hospital, London.

Up to half a million Britons have a degree of sight loss due to glaucoma. ‘ Most cases are picked up by opticians, but there’s a high rate of under- diagnosis.’ it’s easy to miss when it is caused not by pressure in the eye, but as a result of problems with blood flow.

RISK FACTORS:

Family history, ethnic group ( Afro- Caribbean, indian and Chinese people are more at risk) and increasing age are the biggest risk factors. Regular sight tests will detect it early and treatments can prevent further damage.

TREATMENTS:

Traditionally, it is treated with eye drops (one to four times a day) that reduce f l uid production or increase its flow out from the eye.

But they can be unpleasant to use and potential side- effects include sleep problems and impotence.

A new ten- minute procedure, selective l aser trabeculoplasty, effectively causes a minor injury to the eye, drawing white blood cells to the area. These clear the blockage as they repair the damage. This is offered on the Nhs. Moorfields is running a trial comparing it against eyedrops.

Between 10 to 20 per cent of patients need surgery. With the standard operation, trabeculectomy, a channel is made in the white of the eye so fluid can drain out. Lasers can also open up the blocked drainage tubes. There is a risk of scarring preventing fluid flow.

With the latest surgery, a device called a trabectome destroys blocked tubes with an electrical impulse. The procedure, which has a small risk of bleeding, i s available only at Moorfields, Musgrove Park hospital, Taunton and the Royal hallamshire hospital, sheffield.

AGE-RELATED MACULAR DEGENERATION

This is characterised by central loss of vision and you lose the ability to see fine details in faces. it’s also difficult watching TV or reading, as objects may seem distorted.

This is caused by damage to the macula, the spot at the centre of the retina (the light-sensitive cells at the back of the eye).

There are two types: dry and wet. Dry is slower to develop, much more common, harder to treat and caused by a build-up of waste products form-

ing deposits ( drusen) t hat dislodge the macula. in wet AMD, whi c h accounts for a tenth of cases, tiny blood vessels grow under the retina, leaking blood and fluid. The dry form can sometimes lead to wet AMD.

RISK FACTORS: smoking increases the incidence of AMD by three times — possibly because the retina is damaged by free radical molecules from cigarette smoke. UV light and poor diet are also implicated. Age is a major risk factor.

TREATMENTS: For dry AMD, there’s little patients can do except take specific high-dose vitamins (see right) to reduce progression of the condition and to prevent wet AMD.

A new drug, Lampalizumab, is being trialled. Given as an eye injection, it targets inflammation and so reduces damage to retinal tissue. Early studies suggest it reduced the progression of dry AMD by up to 44 per cent.

Another new option at some private clinics is the io1AMD lens. This tenminute procedure involves replacing the patient’s lens with two artificial lenses, one in front of the other.

This works like a telescope, magnifying an image and diverting it to a healthier part of the retina, which takes over the role of the macula to improve vision. it costs £9,750 per eye. studies on the results are due to be published.

For wet AMD, injections into the eye seal leaking blood vessels to stop the problem worsening and sometimes i mproving vision. Patients need four to eight injections a year for life. The drugs Lucentis, Avastin and a newer product, Eylea, i nhibit proteins called Vascular Endothelial Growth Factor ( VEGF), which causes abnormal blood vessels to grow. injections must be given within weeks of symptoms appearing to be effective (Eylea may be more effective so you need fewer jabs).

Two drugs being trialled, Fovista and DARPIN, ‘potentially may be more potent,’ says simon Kelly, an ophthalmic surgeon at the Royal Bolton hospital.

A new technique, Oraya’s iRAY, uses low voltage X-ray beams to stop abnormal blood vessels growing and reduce inflammation and scarring. A trial at King’s College hospital London found it reduces the number of injections needed. Not available on the Nhs, it costs from £4,000 privately.

CATARACTS

CATARACTs are cloudy patches that form on the lens, commonly caused by ageing. symptoms include

cloudy or blurred vision or small patches of vision loss occurring gradually. At first, you might think your glasses are dirty. You may also need extra light to see smaller print.

RISK FACTORS: Getting older, smoking, excess drinking, diabetes and family history.

TREATMENTS: The only treatment is to have the cataract removed — more than 350,000 operations are performed every year.

Not everyone needs surgery as their cataract is not affecting their vision.

Traditionally, surgery has involved removing the cloudy lens through a 2-3mm incision in the eyeball using a metal blade and replacing it with a clear plastic one.

‘such small incisions do not require stitches, there is minimal disruption of the eye and visual recovery is quick,’ says Vincenzo Maurino, a consultant ophthalmic surgeon at Moorfields. Most patients can resume their normal life in a few days. First , the lens is softened and broken up using high frequency ultrasound and the fragments are flushed out. The latest advance is where the surgeon operates the laser via a robot. This i s said to be more accurate, but there is not yet scientific evidence that it’s superior. The replacement lens can be used to correct short or longsightedness or astigmatism. Patients should discuss their needs with the surgeon.

‘Most prefer good distance vision without glasses after the op, but they will need reading glasses for close work,’ says Mr Maurino.

You can also get multifocal lens implants that work in a similar way to varifocal glasses. it’s available privately, from £6,950 per eye.