When blurred vision is a sign of a stroke — in your EYE
WHEN Adam Schreer woke t o f ind t he s ight in his left eye partly blocked, he thought his d og h ad s cratched 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 f rom t he b ottom’, t hat m orning l ast February was actually a sign that he was suffering a non-arteritic anterior ischemic optic neuropathy (NAAION), also known as ‘eye stroke’.
At f irst, h e t ried t o i gnore t he ‘ 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 a nd h is w ife R achael, 4 5, w ent t o have his eyes tested. The optometrist said there were signs that it could be a brain-related problem and told the couple t o g o t o A &E. T hat u rgency w as 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 (fromtheopticdisc)andtransmits visual impulses to the brain.
‘Eye s troke’ i s a l oose t erm that’s useful to help people understand t he s uddenness of what has happened, although the mechanisms are d ifferent t o w hat o ccurs in a stroke.
The condition is not included in the Royal National Institute of Blind People’sonlinelistofeyeconditions and there is no national protocol for d iagnosis o r t reatment. A s 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 R achael. ‘ The d octor s aid h e had n o i dea w hat w as w rong and we were discharged.’
Adam went back to work and tried to carry on as n ormal. B ut a n a ppointment six w eeks l ater s howed h e’d suffered a n ‘ eye s troke’. ‘ The doctor told us: “We don’t know much about why it happens,” ’ says Adam.
JAMES ACHESON, a consultant neuroophthalmologist at the N ational H ospital 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 — m eaning 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 pressurethatcutsofftheblood supply to the nerve.
It d eprives t he o ptic n erve of oxygen and results in d amage to all or part of the nerve, causing visual d isturbances, as signals are no l onger t ransmitted t o t he brain as they should be.
Those with poor circulation, o ften a s a r esult o f t ype 2 d iabetes, s leep a pnoea a nd raised cholesterol, are most at risk.
Symptoms v ary b ut, o ften, patients experience a white spot in the centre of their vision, with blurred or no vision a round t he p eriphery. At its worst, an ‘eye stroke’ leaves the patient blind.
‘Eye stroke’ patients have a 30 p er cent risk of it h appening in the second eye within three to five years, because it can cause permanent swelling of the ‘optic disc’, a tiny structure lessthan2mmwide.Thisc ompresses nerve fibres in the optic nerve.
There i s n o p roven e ffective treatment f or a n ‘ eye s troke’, though it’s been suggested steroids c an h elp, b y c utting inflammation. This can improve c irculation a nd e ase compression o f n erve f ibres.
A 2008 trial showed s teroids can improve vision and p ossibly p revent f urther ‘eye strokes’ in somepatients, according to the journal Graefe’s Archive for Clinical and Experimental Ophthalmology.
The s tudy i s c ontroversial, says Mr Acheson, partly as steroids c arry r isks, i ncluding s ickness, m ood c hanges a nd a remote risk of triggering a second ‘eye stroke’. ‘But for the right patient who can start treatment quickly, steroid therapy is animportant o ption,’ h e a dds.
Larry Smith, a 45-year-old writer f rom N ottingham, w as given t he t reatment a fter h e 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 d iscovered n aaion.org, which g ave d etails o f s teroid therapy, and consulted a neuro-ophthalmologist at a private hospital in Nottingham, w ho a greed t o p rescribe steroids. Side-effects led to him s topping t he m edication after a week — but Larry is adamant it was worth it.
SCANS showed that s welling i n t he o ptic nerve i n t he a ffected 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,includingglaucomaand ‘eye strokes’, could one day be a cure.
Another d rug t hat i s b eing d eveloped b y a n I sraeli f irm t emporarily b locks p roteins thought t o r educe t he o ptic nerve’s capacity to recover from d amage c aused b y l ack of o xygen. I f t aken w ithin 1 4 days o f a n ‘ eye s troke’, i t m ay stop further loss of vision.
But it could be five to ten years before these are a reality. A nd f or A dam, i t w ill 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 h as f ound h elp f rom the c harity S upport 4 S ight, which helped him access technology t o k eep w orking, such as a magnifiedc omputer screen.
He says: ‘We manage well. Others aren’t so fortunate.’