4.1.6 Flashcards
What is the formula for calculating power of a lens required to focus at any distance and give an example using someone who requires reading at 40cm
1/dist(m) = Dioptres
1/0.4 = +2.50D lens is required for seeing at 40cm
What is the formula for calculating focal length (viewing distance) of a lens
F=1/D
If lens has a power of +2.00D then F=1/2.00D
= 0.50m
= 50cm
What to do if someone uses more than half of their total accommodation
Px requires an ADD
If a px has 6D of accommodation and looks 1m away how much do they use
D=1/dist(m)
1D used, 5D leftover
If a px has 4D accommodation and a working distance of 40cm. How much accommodation are they using and have leftover. And which ADD do they require
D=1/0.4= 2.50D being used which means 1.50D leftover. Because this is less than half the total accommodation that px has another +0.50ADD is required to reach at least half the total accommodation so +0.50ADD
What are the three kinds of vocational dispensing
Sportswear - specialised eye wear for sports activities eg goggles
Occupational - tailored to specific jobs eg superspreaders
Special optical appliances - for specific visual impairments eg low vision aids/prism lenses
How far can you see with a super reader 1, what’s it designed for and examples of jobs it can be used in
Clear vision up close and up to 1m away
Designed for prolonged concentrated tasks while maintaining natural posture
E.g office work
How far can you see with a super reader 2, what’s it designed for and examples of jobs it can be used in
Clear vision up close and up to 2m
Good for small group social interactions
Eg playing board games, meals out, cooking
How far can you see with a super reader 3, what’s it designed for and examples of jobs it can be used in
Clear vision up close and up to 3m
Great for larger social interactions
Eg lecturers, till cashiers
