Miscellaneous

Question 0

One meter has the power of how many diopters?

Answer 0

1

Question 1

Formula to find power of a lens:

Answer 1

F+B=P

(Front of lens + Back of lens = Power of Lens(

Question 2

1” = _____mm

Answer 2

25.4

Question 3

Formula to find Focal Length:

Answer 3

F= 1/D

Question 4

Characteristics of Minus Lenses

Answer 4

• minify image
• thinner middle
• with motion
• are for myopia only

Question 5

Minus lens shapes

Answer 5

1. Bi-concave
2. Piano-concave
3. Meniscus

Question 6

Plus Lens Shapes

Answer 6

1. Bi-convex
2. Plano-convex
3. Meniscus

Question 7

Characteristics of Plus Lenses

Answer 7

• magnifies
• thick center
• against motion
• corrects: hyperopia, presbyopia & aphakia

Question 8

Light rays become parallel at how many feet?

Answer 8

20 (to infinity unless interrupted)

Question 9

Three Bands of Ultra Violet Light:

Answer 9

A B C

A & B: use UV protection
C: is absorbed by atmosphere

Question 10

The separation of Light Rays into Colors is called:

Answer 10

Dispersion

Question 11

Reverse Slab is made in only:

Answer 11

CR-39 & ST28

It is pre-made on the front of the most plus lens

Question 12

Purpose of slab off

Answer 12

To balance the prism on bi-focals that have a imbalance due to rx,
Add slab off to grind a new oc on the back of the most minus or least plus lens.

Question 13

Index of Refraction and ABBÉ value of:

CR-39

Answer 13

1.49

59-60

Question 14

Index of Refraction and ABBÉ value of:

Crown Glass

Answer 14

1.523

60

Question 15

Index of Refraction and ABBÉ value of:

Flint Glass

Answer 15

1.70

30-55

Question 16

Index of Refraction and ABBÉ value of:

Hi-index

Answer 16

1.60

43

Question 17

Index of Refraction and ABBÉ value of:

Polycarbonate

Answer 17

1.58

29-31

Question 18

Characteristics of CR-39

Answer 18

Plastic
“Columbia Resin 39” was the 39th batch.
Tints great.

Question 19

Characteristics of crown glass

Answer 19

Twice as heavy as plastic. Great optics. Very durable. Uv coating is ugly yellow. Tints are made in the glass

Question 20

Flint glass

Answer 20

Had flint & lead oxide to refract more. 1.70. heavy. Not used any more

Question 21

To find the frame pd:

Answer 21

Eye size + dbl

Question 22

To find blank size:

Answer 22

Frame PD (eye size + dbl) - patient PD = total decentration. Add ED + total decentration

Question 23

Details of the drop ball test

Answer 23

5/8 inch ball
6/10ths of an ounce
Dropped 50 inches

Question 24

Splay of nose pads

Answer 24

Flat side of nose

Question 25

Frontal nose pads

Answer 25

Pressure on top or bottom of nose pad

Question 26

Vertical nose pad

Answer 26

Pad too close to eye

Question 27

Dress eyewear

Answer 27

Z80.1

Question 28

Industrial eyewear

Answer 28

Z87.1

Question 29

Base curves of lenses

Answer 29

``` Plano -600----- up +200 -400----- -600 +400 -200----- -400 +600 +200 ---- -200 +800 +200 ----- +500 +1000 +500 ---- +800 +1200 +800-----+ ```

Question 30

What are light waves measured in?

Answer 30

Nanometers

Question 31

What is the longest and shortest waves?

Answer 31

Red is longest and violet is shortest.

Question 32

Uv is just beyond what spectrum

Answer 32

Red