New scientific research from Germany shows that seven out of ten patients
are left with defective vision after laser surgery. Poor night vision, nyctalopia,
is caused by the eyes inability to respond quickly enough to changing levels
of light, causing glare, ghosting, halos and starbursts. This is corrected
in most patients by glasses. However, if you've had laser surgery, the condition
may be untreatable. At Hertfordshire Police HQ, Louise Mahon answers 999
calls. She wanted to be a policewoman but her eyesight wasn't good enough.
Louise hoped laser surgery would get her in to the Police Force but, by
the time she had the procedure, it was too late. The Home Office had issued
new guidelines that no one who has had laser surgery should join the police.
It is not just the Police Force who have adopted these rules. The Fire Brigade,
Lifeboat Service and the Civil Aviation Authority have also decided not
to recruit laser eye patients. The CAA says "laser procedures may produce
side effects of glare and distortion of vision .... the long- term effects
are unknown and laser surgery is not recommended for aircrew." Consultant
ophthalmologist, William Jory, also has reservations. He used to perform
laser surgery until he heard worrying research presented at international
scientific meetings. He says: "I have been able to demonstrate a loss
of night vision in my laser cases, not all of them but a majority, approximately
80 per cent." When the reports of night vision loss were confirmed
William Jory stopped using the laser for the treatment of shortsight. In
Germany if you have a car accident at night, you may be required to sit
a night vision test. If you fail it, under German law, you'll be held responsible
for the accident. The experimental ophthalmology department at the University
of Tubingen Eye Hospital has been carrying out tests on post-operative laser
patients for nearly 10 years. Its latest findings show that, despite improvements
in technology, over 70 % of patients are still failing the contrast test
This means it is difficult to make out objects at night, and 50% are failing
what's known as the mesometre test. That means under Germany law they are
unfit to drive. In Britain there's no night vision test for drivers, so
Healthcheck brought people who've had laser surgery to the Transport Research
Laboratory in Berkshire for sight and driving tests. Our volunteers took
two simple sight tests. First the contrast test - a variation on the traditional
sight test, except it measures how well you can pick out objects in the
dark. With good night vision you should see 9 lines of letters. If your
night vision is poor, you'll have difficulty with the last few lines, and
that means your night vision is affected. Optometrist Nigel Burnett Hod
found that most of our volunteers had problems with those bottom lines.
For Healthcheck he devised a special glare test. He found that, among nine
people that represent a successful group of laser patients, two thirds of
them do have slight night vision problems - a little bit of flare, glare
and hazing. So what was their driving like after midnight on a rural road?
The volunteers had to read two signs. Drivers who'd not had laser surgery
read them at 55 metres. But four out of five who'd had the surgery scored
much worse. In line with German research, most of those we tested had defective
night vision. It may have been poor before surgery, but the lasers hadn't
corrected it. In some jobs and road situations, poor night vision could
be disastrous. For more information and advice, you can contact the RNIB
on 0870 010 7070.
Just on the same theme you can read this article, appeared on Canadian
Press in 2002: Laser operations
may reduce your night vision
Refractive Surgery Working with people's eyes
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