4.2.2 - Application of Complex LVAs

Question 1

what is acuity resevere?

Answer 1

we need 2:1 for fluent reading and 1:1 for spot reading

Question 2

why do we use a hand mag with dist gls?

Answer 2

1. Focal point - the px vision is normal state so the mag does the work - reading may bring interferance
2. FOV - dist will bring a better fov then reading

Question 3

what is nominal mag?

Answer 3

x = f/4

Question 4

what is trade mag?

Answer 4

+4.00DS or 4D of acc + mag to the eye

Question 5

what are the positives of a stand magnifier?

Answer 5

1. stability - fixed - easy to maintain distance and reducing hand fatigue
2. Constant focus : image remains in focus
3. Hands free
4. Built in lighting
5. range of Mags - can change according to specific needs

Question 6

Negatives of a stand mag?

Answer 6

1. Limited portability - not good for people who need it away from their desk
2. Resticted FOV - fixed distance - may have to move the object under
3. Flat surface needed
4. expensive
5. large size

Question 7

Positives of bar / flat feild mags?

Answer 7

1. easy ot use
2. full line viewing = easier to read
3. Portable - light and thin
4. durable - double arcylic = does not shatter or scratch
5. minimal visual distortion as it is flat

Question 8

negatives of bar / flat mags?

Answer 8

1. limited mag power
2. restircited fov
3. Need external lighting
4. only one mag - cannot change

Question 9

pos of spec mags?