Vision Screening Why? Tools of the trade
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Transcript of Vision Screening Why? Tools of the trade
Vision Screening
•Why?•Tools of the trade
Why?
1. Law
1.Vehicles (cars & heavy duty)Regulation 102 of the National Road Traffic Act (93
of 1996)
2.Driven machineryDriven machinery regulations (Feb 2005) of the
Occupational Health & Safety Act
2. Employee productivity
– Clear & comfortable vision
– Headaches, neck aches
Why?
Regulation 102 of the National Road TrafficAct (93 of 1996)
Codes A1 to EB (light vehicles):
• 6/12 in each eye•One eye worse than 6/12, other 6/9 or better
Codes EC & EC1 (heavy duty vehicles):
• 6/9 in each eye•One eye worse than 6/9, too bad…
Minimum visual acuity
Regulation 102 of the National Road TrafficAct (93 of 1996)
Minimum visual fields
Codes A1 to EB (light vehicles):
• 70° temporal each eye•One eye < 70°, at least 115° total horizontal field (both eyes together)
Codes EC & EC1 (heavy duty vehicles):
• 70° temporal each eye•One eye < 70°, too bad…
Driven machinery regulations
• Same as for codes EC & EC1 (heavy duty)– 6/9 each eye– 70° temporal visual field each eye
PLUSStereopsis (3-D vision)
• Existing PDP– Same as codes EC & EC1 (no stereopsis
required!)
Tools of the Trade
All-in-one vision screeners
Keystone vision screener
Keystone Telebinocular
All-in-one vision screeners
Pro’s
•Visual acuity (far & near)•Stereopsis•Colour vision•Muscle balance
All-in-one vision screeners
Cons
• Patient observation more difficult, eg. squinting or viewing through incorrect part of spectacles
• Stereopsis test difficult to explain• Proximal accommodation
Tools of the trade
Visual acuity
Snellen chart
1800’s – stood test of time
Wall chart
Chart projector
Correct use!!
•Test distancesee ‘Eye Care Topics → Visual Acuity’ on www.occuvision.com
•Gentle eye cover•Watch person for cheating
Snellen chart
Colour vision
Ishihara plates
-Simple
Colour vision
Farnsworth D-15
Good adjunct to Ishihara
Stereopsis
Randot stereotest
NB presbyopes towear near visioncorrection
Autorefractor
• Refractive state of eye
• Keratometry– Measures basic
corneal curvature
Non-contact tonometer
Intra-ocular pressure• Glaucoma• Peripheral field loss
> 42 <42 > 2 Yrs < 2 Yrs or N/A
> 0.75 D
< 0.75 D
YES
NO > 21 mmHg
< 21 mmHg YES NO
Age of employee
Age of Spectacles
Tonometry
Snellen VA in best eye worse
than 6/9
Ametropia (habitual)
Myopia, Hyperopia, Astigmatism
spectacles
PASS.
RETURN TO WORK
FURTHER
EVALUATION NECESSARY
Near vision , esp. at night; Frequent
temporal & frontal H/A’s; Asthenopia
Thank you