When blurred vision is a sign of a stroke – in your eye

When Adam Schreer woke to find the sight in his left eye partly blocked, he thought his dog had scratched him as he slept.

‘If anyone had told me then that within six months I would have lost the sight in both my eyes, I’d have said they were crazy,’ says Adam, 51, a builder from Brentwood, Essex.

Yet the strange sensation in his left eye, ‘as though a shutter was coming up from the bottom’, that morning last February was actually a sign that he was suffering a non-arteritic anterior ischemic optic neuropathy (NAAION), also known as ‘eye stroke’.

Common: ‘Eye strokes’ are a disorder which are thought to affects one in 10,000 people

At first, he tried to ignore the ‘shutter’ effect but, within two days, vision in the bottom half of his left eye was totally black and the upper half was ‘pixellated like a kaleidoscope’, so Adam and his wife Rachael, 45, went to have his eyes tested. 

The optometrist said there were signs that it could be a brain-related problem and told the couple to go to A&E. That urgency was well-founded. 

‘Eye stroke’, a disorder that affects one in 10,000 people, destroys vision partially or fully with shattering suddenness. It’s caused by poor circulation in the blood vessels that feed into the optic nerve, which runs from the back of the eye (from the optic disc) and transmits visual impulses to the brain.

‘Eye stroke’ is a loose term that’s useful to help people understand the suddenness of what has happened, although the mechanisms are different to what occurs in a stroke.

The condition is not included in the Royal National Institute of Blind People’s online list of eye conditions and there is no national protocol for diagnosis or treatment. 

As a result, the problem can be missed, even by specialists, or patients may not be offered treatment that might save their vision.

‘People are often told it’s macular degeneration or glaucoma and that can wrongfoot them for years,’ says Peter Leeflang, the U.S. founder of naaion.org, a global patient support group that he set up in December 2016 after losing most of his sight in both eyes following ‘eye strokes’.

Adam went to A&E at Moorfields Eye Hospital in London. But ‘all the tests came back normal,’ recalls Rachael. ‘The doctor said he had no idea what was wrong and we were discharged.’

Adam went back to work and tried to carry on as normal. But an appointment six weeks later showed he’d suffered an ‘eye stroke’. ‘The doctor told us: “We don’t know much about why it happens,” ’ says Adam.

It¿s caused by poor circulation in the blood vessels that feed into the optic nerve, which runs from the back of the eye (from the optic disc) and transmits visual impulses to the brain

It’s caused by poor circulation in the blood vessels that feed into the optic nerve, which runs from the back of the eye (from the optic disc) and transmits visual impulses to the brain

James Acheson, a consultant neuro-ophthalmologist at the National Hospital for Neurology and Neurosurgery in London, says he ‘sees several patients with this condition every year’.

Similar to some strokes in the brain, ‘eye stroke’ is ‘ischaemic’ in nature — meaning it’s caused by a sudden loss of blood. But while in a stroke, this is due to a blockage of an artery, in ‘eye strokes’ it is caused by a drop in blood pressure that cuts off the blood supply to the nerve.

It deprives the optic nerve of oxygen and results in damage to all or part of the nerve, causing visual disturbances as signals are no longer transmitted to the brain as they should be.

Those with poor circulation, often as a result of type 2 diabetes, sleep apnoea and raised cholesterol, are most at risk. Symptoms vary but, often, patients experience a white spot in the centre of their vision, with blurred or no vision around the periphery. At its worst, an ‘eye stroke’ leaves the patient blind.

‘Eye stroke’ patients have a 30 per cent risk of it happening in the second eye within three to five years, because it can cause permanent swelling of the ‘optic disc’, a tiny structure less than 2mm wide. This compresses nerve fibres in the optic nerve.

There is no proven effective treatment for an ‘eye stroke’, though it’s been suggested steroids can help, by cutting inflammation. This can improve circulation and ease compression of nerve fibres.

A 2008 trial showed steroids can improve vision and possibly prevent further ‘eye strokes’ in some patients, according to the journal Graefe’s Archive for Clinical and Experimental Ophthalmology.

The study is controversial, says Mr Acheson, partly as steroids carry risks, including sickness, mood changes and a remote risk of triggering a second ‘eye stroke’. ‘But for the right patient who can start treatment quickly steroid therapy is an important option,’ he adds.

Larry Smith, a 45-year-old writer from Nottingham, was given the treatment after he was diagnosed with an eye stroke last July. He’d woken one morning to ‘flickers of flame-like threads to a full-on blur’ in the bottom of his left eye. He discovered naaion.org, which gave details of steroid therapy. He consulted a neuro-ophthalmologist at a private hospital in Nottingham, who agreed to prescribe steroids.

Side-effects led to him stopping the medication after a week, but Larry is adamant it was worth it. Scans showed swelling in the optic nerve in the affected eye was reduced ‘to acceptable levels’, he says, and he describes the sight he still has in his left eye as ‘clear and sharp’.

A research project using gene therapy drugs to regenerate damaged nerve tissue in optic nerve conditions, including glaucoma and ‘eye strokes’, could one day be a cure.

Another drug being developed by an Israeli company, temporarily blocks proteins thought to reduce the optic nerve’s capacity to recover from damage caused by lack of oxygen. If taken within 14 days of an ‘eye stroke’, it may stop further loss of vision. But it could be five to ten years before these are a reality. And for Adam, it will be too late.

Two months after being sent home without treatment, he woke to the same, shutter-like feeling in his right eye. Despite knowing of the benefits of steroid treatment by then, it sadly had no impact and he is now registered blind. 

Adam has found help from the charity Support 4 Sight, which helped him access technology to keep working, such as a audio mail and a magnified computer screen.

He says: ‘We manage well. Others aren’t so fortunate.’

For more info, visit: support4sight.org.uk

 



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