visual standards for driving Flashcards
what is the standard of vision for a group 1 driver?
in good daylight, be able to reaf a reg plate containing 79mm high and 50mm wide letters from 20m AND va must be at least 6/12 (0.5)
who are group 1 drivers?
ordinary family cars and light vans
in terms of visual angle which snellen is equivalent to the number plate standard?
6/15 BUT NOT PRECISE
with 6/12 VA would a px pass the number plate test?
6/12
which VA should you be able to advise they can meet the driving standard?
6/7.5
which px’s should be advised to check their ability to read a number plate, as they might not be able to?
drivers with acuity 6/9 to 6/12
who are group 2 drivers?
LGV (large good vehicles - lorries) and PCV (passenger carrying vehicles - buses)
what VA must group 2 drivers achieve in the better eyes?
6/7.5
what VA must group 2 drivers achieve in the worse eye?
6/60
what is the limit of corrective power for group 2 drivers?
< or = +8.00D
NO CL LIMIT
why do group 2 drivers have more strict standards?
they have responsibility of goods or people
why do the new standards for group 2 drivers not help optoms?
- difference between 6/7.5 and 6/9 is small
- not every snellen chart has a 6/7.5 line
- test chart must be accurately at 6m or accurately scaled
- +8.00 doesn’t specify if its the mean sphere power or highest powered meridian
is there a statutory requirement in UK legislation for visual fields for group 1 drivers?
no but the second EC directive applies
what is the minimum field of vision for safe driving?
a field of vision of at least 120 degrees on the horizontal measured by the goldmann perimeter using the III4e settings or eqivalent
AND
no homonymous or bitemporal hemianiopic or quadrantopic defects in fov within 20 degrees of fixation above or below
what does the group 2 driver field requirement look like?
tube sign (LOOK AT SLIDE 15)
