Lensometry Multifocal

Question 1

What is the green and orange light on the lensometer for

Answer 1

Green for light lenses

Orange for sunglasses

Question 2

Lenses that contain two or more loess power to let you see at different distances

Answer 2

Multifocal

Question 3

Who wears multifocal

Answer 3

Over 40, children

Question 4

Types of multifocal

Answer 4

Progressive
Bifocal
Trifocals

Question 5

Must you set the axis on 180 before doing lensometry>

Answer 5

No

Question 6

Line multifocal design

Answer 6

Front surface design

Question 7

What is the distance between the optical center and the top of a bifocal

Answer 7

3-5mm

Question 8

What is the distance between the optical power and the trifocal add power

Answer 8

1-3mm

Question 9

How to read the add power on lensometer

Answer 9

Go from single to single or from cyl to cyl. Don’t fluctuate between the two

Question 10

What side of the lens is thicker on multifocal

Answer 10

Front

Question 11

How do you read the add power on a multifocal in lensometry

Answer 11

Flip the glasses around and find it that way. Also check the distance power again flipped and subtract the difference between the two, to make sure you are using a uniform side to do this.

Question 12

When should you do the proper front/back vertex reading for add power

Answer 12

When the Rx is: +/-5 with an add of +2.50 or greater

Question 13

Corrective lenses used in eyewear to correct presbyopia or other accommodation issues

Answer 13

Progressive lenses

Question 14

Types of progressives

Answer 14

Multifocal, no lines, PAL

Question 15

Downside of progressive lenses

Answer 15

Distortion on the side

Question 16

Designates the point on a lens that should be placed at the center of the pupil

Answer 16

Fitting point

Question 17

Areas used to verify prescribed distance power

Answer 17

Distance reference circle

Question 18

Optical center of a PAL, used to check prism

Answer 18

Prism reference point

Question 19

Located on nasal side, under micro-circles/references lenses type/material

Answer 19

Alignment markings and manufacturing logo

Question 20

Used to verify total near point

Answer 20

Near reference point

Question 21

Located on temporal side/ used to verify add power

Answer 21

Add power

Question 22

What side is is the add power always on

Answer 22

Temporal side

Question 23

When reading progressives, it is important to mark these points on each lense before proceeding

Answer 23

Dot it up

Question 24

Where is the reference point usually

Answer 24

4mm up from the 180 line

Question 25

Where is the prism in a progressive lens

Answer 25

Right int he middle of the 180 line

Question 26

Reading distance on progressive lenses

Answer 26

Distance reference point

Question 27

Where do you read the add power on a progressive lens

Answer 27

Read add power from the near reference point (down to the nasal) Some manufacturers tell you not to do this. Short frames will read inaccurate. Digitally surfaced lenses will not be in quarter increments. Can be a +1.56 or something to that effect

Question 28

How do you read the prism on a progressive

Answer 28

Right in the middle of the 180 line

Question 29

Triangulated pieces of glass that pass through it and change the direction of light

Answer 29

Prism

Question 30

Thinner in the middle, thicker on the side

Answer 30

Minus

Question 31

Thicker inthe middle

Answer 31

Plus

Question 32

A unit that describes the power of a prism to produce a cone centimeter deviation in a ray of light at a distance of one meter from the lens

Answer 32

Prism diopter

Question 33

Involves the grinding of the surface of a lens during a manufacturing

Answer 33

Ground in prism

Question 34

Involves decentering the optical center to utilize the pristmatic effects of sphere-cylindrical lens. Prentice's rule

Answer 34

Induced prism

Question 35

How do you know you have ground in prism

Answer 35

It will never lien up with the mires

Question 36

How do you know you have induced prism

Answer 36

The mires can only be centered when the lens is decentered

Question 37

What kind of lenses can you induce prisms into

Answer 37

Single vision lenses

Question 38

What kind of prism has to be in progressives

Answer 38

Ground in

Question 39

Minor powers and prism

Answer 39

Cannot induce prism

Question 40

Unwanted prism

Answer 40

Calculate prentice rules | Can be vertical and horizontal imbalance

Question 41

Too much BD prism

Answer 41

Vertical objects appear taller than they are. Looks like you are walking up a hill

Question 42

Too much BU prism

Answer 42

Vertical objects will appear smaller

Question 43

Too much BI or BO prism

Answer 43

Horizontal lines will have a curve to them

Question 44

PAL and prism thinner

Answer 44

In PAL, surface power power increases as you go down, but it also increases thickness on the opposite side. Manufacturers want their lenses to look as good as possible, use prism thinning which induces prism, whether Rxed or not. Most thinning is BD

Question 45

Prism that is up in both eyes, or down in both eyes

Answer 45

Cancel each other out

Question 46

Prism that is in in one eye, and out in the other eye will

Answer 46

Cancel each other out

Question 47

How do you read prism on a progressive lens

Answer 47

Read from the prism reference point

Question 48

3 ways you can get prism from a single vision

Answer 48

Exam history Lab ticket Getting optical center while patient wears them