Lesson 12 - Frame Adjustment Basics and Dispensing

Question 1

Hot salt pan

Answer 1

Heated table salt or glass beads used to make frames pliable. Pans using hot salt or glass beads have some additional drawbacks. For example, they can damage certain frame materials and lens coatings.

Question 2

Forced hot air warmer

Answer 2

Allows control of temperature and direct steam to evenly heat the area of frame to make it pliable

Question 3

Lens caliper

Answer 3

Used to measure the thickness of a lens

Question 4

Distometer

Answer 4

Measures vertex distance. If the vertex distance of the frames chosen is different than the 12 millimeters measured by the photopter, then the optician will need to make a vertex adjustment by using the distometer

Question 5

Pantascopic tilt

Answer 5

Pantascopic tilt is the process of angling a frame front downward slightly, so the lower part of the frame is closer to the face than the top part, allowing for the optical center to stay in front of the pupils when the eyes move downward.

Question 6

Face form

Answer 6

How a pair of glasses wrap around a person’s face—positive (outward curve following face), negative (Inward curve), or neutral face form (No curve).

Question 7

Vertex

Answer 7

Distance between the cornea and the back of the eyeglass lens

Question 8

Four-point touch

Answer 8

Test to check the alignment of the frame. On a flat surface, both tops of the earpieces and both endpieces of the eyewire should touch the surface, as a starting point. Adjustments can be made from this point.

Question 9

Blocking

Answer 9

Correctly positioning a lens so it can be cut to fit a frame

Question 10

Lens block

Answer 10

Small plastic disk the size of a nickel with adhesive tabs on both sides of it. One side of the block is attached to the uncut lens, the other side of the block is attached to the chuck of the edger to hold the lens while the blade of the edger cuts the lens.

Question 11

Edging

Answer 11

Using an optician machine, called an edger, to cut the lens to fit in a frame. These days, most lens edgers are computerized and will calculate all the decentration needed. All you’ll need to enter is the person’s PD and the desired seg heights. Once the edging is done, it’s time to add any tints and polish the edges of the lens. After that, the lens is ready to go in the frame.

Question 12

MRP raise or drop

Answer 12

Vertically decentering a lens when there is an imbalance between the two eyes

Question 13

The eyeglasses you get back from an optical laboratory should be trued. Not all glasses, however, will be trued when you get them. What does trued mean?

Answer 13

This means that they should be well aligned to fit on a perfectly standard face.

Question 14

The tool you’ll reach for the most is what?

Answer 14

An optical screwdriver

Question 15

Always select the ___ screwdriver blade you can use without scratching a frame.

Answer 15

Always select the widest screwdriver blade you can use without scratching a frame.

Question 16

Eyeglass screws can occasionally loosen, especially in the hinge as the temples are opened and closed. You can sometimes put what to help prevent it from backing out?

Answer 16

You can sometimes put a tiny drop of Loctite or clear fingernail polish on the end of a screw before inserting it to help prevent it from backing out.

Question 17

Describe pliers used for angling the temples

Answer 17

Have two large pads on the end and are square

Question 18

What is the function of pliers for eyewires and nosepads

Answer 18

Pliers for straightening out the eyewires and rounding the nose pads

Question 19

Nosepad pliers

Answer 19

Pliers for angling the nose pads resemble needle-nose pliers. Nosepads can be adjusted as such: you can bend them outward or inward, you can tilt them up or down, or you can angle them flatter or straighter.

Question 20

Lens axis pliers for astigmatism

Answer 20

Axis pliers for adjusting the axis to align with the prescription. A lens for a person with astigmatism has two different powers in two different orientations. The prescription for a lens like this can be incorrect if the lens doesn’t sit in exactly the proper position in the frame. To turn the lens so it’s aligned correctly in the frame, we use lens axis pliers. They grab the lens on the front and back so we can rotate it.

Question 21

What are some important rules when using hot salt pans and forced hot air frame warmers?

Answer 21

Only heat the part of the frame you’re working on—and you’ll keep moving the frame as it heats to make sure it heats evenly. Also, you’ll need to know what temperatures your frame and lens materials can withstand.

Question 22

Dispensing

Answer 22

The term used when the prescription glasses are presented to your client

Question 23

The handiest tools are what? Why?

Answer 23

The handiest tools are your own two hands. You can make several frame adjustments without even picking up a pair of pliers. When you use your hands and fingers to make adjustments, you can apply the right amount of pressure in just the right places and directions. Also, you don’t need to worry about scratching frames or lenses (something you need to be very careful about with a metal tool).

Question 24

In general, we aim for a pantoscopic tilt of about how many degrees? When dealing with lenses that have a reading portion such as a bifocal portion at the bottom of the lens, or when we’re giving customers lenses that are custom-designed, a goal for the pantoscopic tilt is how many degrees?

Answer 24

In general, we aim for a pantoscopic tilt of about 10 degrees. When dealing with lenses that have a reading portion such as a bifocal portion at the bottom of the lens, or when we’re giving customers lenses that are custom-designed, a goal for the pantoscopic tilt is 5 to 15 degrees.

Question 25

Every two degrees of pantoscopic tilt added to a frame front effectively what?

Answer 25

Every two degrees of pantoscopic tilt added to a frame front effectively lowers the optical center of the lens by one millimeter.

2° of pantoscopic tilt = optical center ↓1 mm

Question 26

Retroscopic tilt

Answer 26

The upper portion of the frame is closer to the eyes than the lower part of the frame. Frames with this type of tilt look odd—and worse yet, people can’t see well with them

Question 27

Orthoscopic tilt

Answer 27

The lenses are the same distance from the eye at the top and bottom of the frame

Question 28

Typically, you’ll aim for a ___ face form. This means what?

Answer 28

Typically, you’ll aim for a positive face form. This means that the frames curve slightly to follow the contours of the face. In this form, the bridge of the glasses will be slightly forward from the endpieces

Question 29

Many of the newer large sunglasses have a high degree of positive face form. How can this be an issue? Where is this often noticed?

Answer 29

Many of the newer large sunglasses have a high degree of positive face form. If the prescription is strong, this amount of face form can distort vision. This is often noticed with curved sunglasses frames.

Question 30

When the optician dispenses glasses, the optician will check the vertex and adjust it. What frame material is easier or harder to make a vertex adjustment?

Answer 30

When the optician dispenses glasses, the optician will check the vertex and adjust it. If the client has a metal frame, the optician can do this easily by adjusting the nose pads or temples. If the client has a zyl frame, it’s harder to make a vertex adjustment—and that’s one reason it’s important to select the correct frame to begin with.

Question 31

If a four-point touch shows that the left temple of a frame is higher than the right temple, what should you do?

Answer 31

Bend the left temple up.

Question 32

If a four-point touch shows that the right temple of a frame is higher than the left temple, what should you do?

Answer 32

Bend the right temple up.

Question 33

You’ll want to place the glasses on your client’s face yourself when?

Answer 33

You’ll want to place the glasses on your client’s face yourself when you start a dispense. This will allow you to feel the fit of the temples and to position the glasses correctly so you can spot any potential issues more easily.

Question 34

Truing is entirely different from real-life adjusting. Why?

Answer 34

Why? Because each face is different. Glasses need to fit snugly and comfortably on a person’s face.

Question 35

Three-point touch

Answer 35

Two ears and a nose, the three points where glasses touch the face.

Question 36

Simple formula for remembering how to bend a temple

Answer 36

Up-Up, Down-Down. In other words, if the right side of the frame sits too high on the person’s face, bend the right temple up (or the opposite temple down). If the left side of the frame is too high, bend the left temple up (or the opposite temple down).

Question 37

How do you fix a frame that tilts to one side?

Answer 37

First, place the frame right-side-up, with the temples open, on a flat surface facing toward you. This might help you see which temple is too high or too low.

Next, you’ll heat the temple (if it’s a zyl or plastic frame) and bend it. Typically, you’ll start at the hinge. If you’re working with a metal frame, you probably won’t need to heat the temple; instead, you can just start bending the temple at the hinge. You can use a pair of hinge pliers to make this job easier.

Then adjust the temples using the simple formula Up-Up, Down-Down.

Question 38

How do you fix glasses that have one side closer to the client’s face than the other side?

Answer 38

Adjust one temple inward or outward. And again, the rule is easy, even though it seems counterintuitive. If the right lens is closer to the eye, you’ll bend the right temple inward (or the opposite temple out). If the right lens is farther away from the face, you’ll bend the right temple farther away from the head (or bend the opposite temple closer). In other words: In-In, Out-Out.

If the vertex is too short or too long for both lenses—that is, if the entire frame front is the wrong distance from the face—you can simply shorten or lengthen the bend in the temple earpieces. If the frame has nose pads, you may also be able to very slightly shorten or lengthen the bend of the pad arms to change the vertex distance.

Question 39

How do you correct and incorrect pantoscopic tilt?

Answer 39

To change an incorrect pantoscopic tilt, you’ll bend both temples slightly at the hinge until they sit correctly on your client’s face. Bending them down will increase the pantoscopic tilt, while bending them up will reduce this tilt.

Question 40

How do you fix glasses that keep sliding off the nose?

Answer 40

Take a look at how the temples curve around the ears. If the temple bends don’t land precisely at the curve of the ears, heat the temple bends, and rebend them so they’re a little closer to the frame front.

A problem with slipping glasses can stem from temples that aren’t spread out enough—or from temples that are spread too far. In either case, you can bend the temples so they’re a correct distance from the head. If the temples are spread too far or they are too narrow, you should also consider narrowing or opening the frame by heating and adjusting the bridge curvature.

Question 41

How do you fix earpieces that hurt a client’s ears?

Answer 41

When eyeglass temples hurt a person’s ears, it’s typically because they’re bent too sharply and they’re hitting the mastoid bone or the back of the ear. Instead, the temples should follow the natural curve of the ear.

Glasses can also hurt if they slip down the nose, placing too much pressure on the backs of the ears. In this case, adjusting the temples (or the nose pads), can fix the problem.

Question 42

Look at the nose pads from where so you can get a better view of the angle of the pads before you adjust them?

Answer 42

Look at the nose pads from above your client’s head so you can get a better view of the angle of the pads before you adjust them.

Question 43

For very wide bridges, the nose pads need to what? For narrow nose bridges, they need to be what?

Answer 43

For very wide bridges, the nose pads need to be wider apart. For narrow nose bridges, they need to be closer together.

Question 44

Try to angle the nose pads to align with the tilt of the nose. How is this done?

Answer 44

To turn the nose pads at an angle, you’ll need to twist the pliers by twisting your wrist. This is a good skill to practice with some old frames or over-the-counter readers.

Question 45

Angle adjustments are especially important when your client has a very flat nose bridge. Why?

Answer 45

Angle adjustments are especially important when your client has a very flat nose bridge. This is the hardest type of nose to fit, because there’s little support for the frame.

Question 46

If the frame is too far out of alignment in the beginning what should you do?

Answer 46

If the frame is too far out of alignment in the beginning, warn your client that you may need to make several large adjustments to the frame and there’s a risk that you may break it in the process. Try to obtain an agreement or informed consent from the person beforehand to make sure he or she is willing to take that risk. If not, recommend a new frame.

Question 47

Steps for using a lens blocker

Answer 47

When you’re blocking a lens, you need to be sure you get the orientation of the lens just right. Remember that if there’s astigmatism, the lens has to give the person more power in one specific direction—and that extra power needs to be in just the right place. If there is a prism prescribed for the lens, you will need to be sure to mark the lens correctly to reflect the amount of prism needed.

1. Always use the lensometer to verify the power of the lens blank you’ll be using before you block the lens in the lens blocker.
2. Mark the lens “R” or “L” with a lens marking pen to identify whether it’s a right or left lens.
3. Use the lens blocker, which will mark an inked spot on the lens, to spot the major reference point(MRP). Remember that when there is no prism prescribed for the lens, the optical center of the lens is the same as the MRP. When there is prism, the MRP is where the pupil should be. This will be a certain distance away from the OC. (In other words, the lens will be decentered.) When there is prism, we sometimes refer to the MRP as the PRP, or prism reference point.

Question 48

You’ll need to do a little math when you’re blocking a lens, because you have to calculate where the wearer’s pupil will be. (This will usually correspond to the MRP of the lens.) For reading glasses, our pupils usually turn slightly inward when we’re looking downward at a near target—for instance, when we’re reading a book. Thus, the distance between them (the near PD) will be a little less than the distance between the centers (DBC) of the lenses. As a result, you’ll need to decenter a lens before attaching the block for a reading lens. How do you calculate the decentration of the lens before putting it on the blocker?

Answer 48

The distance between the lens centers (DBC) is the same as the distance between the lenses (DBL) + the eye size (a measurement) of one lens.

DBC = DBL + eye size

Once you know your DBC, you can do the next step. Here’s how you calculate the decentration per lens:

(DBC-PD) ÷ 2 = decentration per lens

(the PD or pupil distance will be given to you on the exam question)

Example: A wearer’s PD is 62mm. The frame size has a dimension of 48mm and a DBL of 20mm. What is the decentration per lens required?

DBC=20+48=68mm
(68mm - 62mm)/2 =3mm

Question 49

To calculate the centration of a flat-top bifocal, you will need to determine the total seg inset required. How do you do this?

Answer 49

Total inset = (eye size + DBL) – near PD

Question 50

To determine the horizontal decentration of a lens when you’re given monocular PDs, you’ll use this formula

Answer 50

Horizontal Decentration = (DBC ÷ 2) - monocular PD

Question 51

The amount that each eye turns inward is especially important to consider when a person is looking through a progressive lens, since each eye has to move through the progressive corridor as it travels from distance to near. In some cases, a person’s eyes don’t turn inward the same amount when the person looks at a near object. When that’s the case, you’ll need to use _____ to measure the amount that each eye turns in and determine the decentration of a lens. What is this called?

Answer 51

In some cases, a person’s eyes don’t turn inward the same amount when the person looks at a near object. When that’s the case, you’ll need to use monocular PDs—that is, separate PDs for each eye—to measure the amount that each eye turns in and determine the decentration of a lens. This is also called a monocular pupillary distance measurement.

Question 52

When you drop the MRP, the distance the eye has to travel from the distance portion to the reading portion of a progressive lens is reduced, so there is less prismatic effect or vertical imbalance. To calculate the MRP vertical raise or drop, you’ll use this formula

Answer 52

MRP Raise or Drop = MRP – (B measurement ÷ 2)

Question 53

If the person is wearing a bifocal and has a vertical imbalance, you’ll calculate the amount of vertical seg drop or raise needed. What is the formula for this?

Answer 53

Seg height change = seg height – (B measurement ÷ 2)