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.

‘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 the 51-year-old builder.

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’.

At first, Adam 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 it could be a brain-related problem and told them 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 those of a stroke.

As a result, the problem can be missed 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 US founder of naaion.org, a support group he set up in 2016 after losing most of his sight following ‘eye strokes’.

Adam went to A&E 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. James Acheson, a consultant neuro- ophthalmologist, 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.

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% 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. 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: ‘But for the right patient, steroid therapy is an important option.’

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 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 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. Steroids had no effect and he is now registered blind.

Adam found help from a charity, which helped him access technology to keep working, such as a magnified computer screen.

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