TOPIC 3: VISION AND DRIVING Flashcards
How do the various visual tests relate to driving safety (i.e. how reduced VA, reduced VF, reduced CS, CVD etc can impact driving)
Reduced VA is
-Associated with higher risk of accidents
-may delay detection of pedestrians
Reduced visual field is associated with
-Decreased driving performance and increased risk of accidents
-Poorer speed matching when changing lanes, lane positioning especially curves
-Slower to react to unexpected developments in the periphery
-Slower to detect pedestrians and detect fewer pedestrians
reduced CS=more difficult to recognize road signs and road danger
Red-green colour deficiency can make it difficult to identify red, orange, yellow and yellow-green objects.
Patients with CVD rely on brightness to discriminate these confusing colours (e.g. yellow is brighter than yellow-green)
Red appears darker and not as eye-catching!
Take longer time to respond to red and amber traffic signal
What are the VA requirements for driving in Sg?
Group 1 Licence (Private)
-Class 1 to 3 driving licence holders (EXCEPT TAXIS) should have VA of at least 6/12 in ONE eye
-If the worse eye has a VA of worse than 6/36, or if the person is monocular, the horizontal
field of vision should be tested
Group 2 Licence (Commercial)
-Drivers of taxis, buses and heavy vehicles (i.e. lorries and trucks) should have at least 6/12 in EACH eye
What are the horizontal visual field requirements for driving in Sg?
ONLY necessary to test when a person is one eyed – i.e. VA less than 6/36 in the worse eye
Such persons must have a horizontal field of at least 120 degrees.
Significant VF defects such as homonymous hemianopia, quadranopia will exclude a person from driving.
They can only drive private vehicles (not commercial)
What are the colour vision requirements for driving in Sg?
For all classes of driving, the driver should be able to identify red, green and amber light
can a person with diplopia drive?
NO.
Do note that the presence of strabismus will not cause a person to be barred from driving; it is the presence of diplopia that bars a person from driving (i.e strabismus may not cause diplopia and person can drive)
can a person with night blindness drive? Which group of people require regular assessments
NO
Marked defect in night vision (i.e. retinitis pigmentosa and advanced chorio-retinitis) should be regarded as a bar to driving.
People with these eye conditions will require regular assessments:
1. High myopia (above 10 dioptres)
2. Macular degeneration
3. Cataract
4. Glaucoma
5. Diabetic Retinopathy
