OO Exam 2

This is the equation for 'minimum blank size' for a 'finished' single-vision lens. What is the equation for 'total decentration?'

(A + DBL) - PD Making the final MBS calculation for a finished lens: MBS = ED + ((A + DBL) - PD) + 2 mm

When measuring seg heights on a patient's old frame to get them readjusted on a new frame, you note that the seg height is 15 mm, and it sits 3 mm below their lower limbus. Measuring the lower eyewire to the lower limbus on the new frame, you get 20 mm. What should the new seg height be?

17 (20 - 3 = 17, the 15 is extraneous info)

Measuring PDs, you get 66 at a distance and 60 at near. What is the segment inset?

3 (66-60 = 6, 6/2 = 3)

When ordering a double-seg lens, the upper segment should be about [this many] millimeters squared in area

9 mm squared (this is adjusted by either using larger frames or bringing the lower seg down slightly)

Monocular PDs and measured MRPs are important for aspheric lenses because the central zone has [this property] and the outer edges have [this property], meaning the central zone must be positioned very carefully

A constant lens surface power; Gradually changing surface powers

A frame with too much face form causes the nasal part of the eyewires to be [a great distance from the ruler/inward compared to the temporal eyewires]

A great distance from the ruler

The bifocal segment most often prescribed for children is [this kind of bifocal style]

A wide flat-top style

Low myopes typically don't bother with multifocals. Why not?

Adds bring their far point to where they can clearly see already - in other words, they're redundant and the patient can simply remove their glasses for clearer vision up close

Temples that [aren't spread enough/are spread too much] tend to slide down the nose, and the ends of the temples pull against the backs of the ears

Aren't spread enough

The seg top is ALWAYS displaced from its original location in the direction of the [apex/base] of the vertically-prescribed prism

Apex (move the seg height towards the 'point' of the prism)

The base direction for PLUS lenses is towards the [center/margin] of the lens

Center

Adjusting MRPs and acquiring monocular PDs is essential when using lenses with higher refractive indexes, to reduce [these]

Chromatic aberrations

Generally eyeglasses should be adjusted so that the lower rims of the frame are [further/closer/parallel] to the face

Closer (provides wider field of view and is more cosmetically appealing)

Nosepads in general should be adjusted so they [do this] as much as possible when fitting a patient

Come into contact smoothly with the surface of the nose

Which of the following are acceptable tool combinations to use to change pantoscopic tilt on metal frames? A. Hand and angling pliers B. Hand and double-padded pliers C. Half-padded pliers and double-padded pliers D. These are all acceptable tools to use together while bending the temple to correct pantoscopic tilt on metal frames

D

You have the patient tilt their head down while looking in front of them to check this during frame fitting: A. Temple spread B. Nosepad adjustment C. Loose lenses D. Vertex distance

D (B might also be true but it's definitely true for D)

Vertex distance is the distance from the [front/back] surface of the spectacle lens to the apex of the cornea

Back

Prism bends light in the direction of the [base/apex], causing the image of the object viewed to be displaced in the direction of the [base/apex], which is where the eye turns to fixate

Base; apex

According to the dispensing textbook, the average vertex distance is about [this many] millimeters: A. 12 B. 13 C. 14 D. 15

C

During initial alignment the splay angle should be about [this many] degrees: A. 10-15 B. 20-25 C. 25-30 D. 30-35

C

Skull and library temples should be fitted so they exude pressure: A. At a single point behind the ear B. At a single point at the root of the ear C. Uniformly across and parallel to the side of the head D. Uniformly across the head with a slight bit of slant

C

The optical center of a lens should be moved [this many] millimeters for every [this many] degrees of pantoscopic tilt. A. 2; 2 B. 1; 1 C. 1; 2 D. 3; 1 E. 2; 3

C

With which of the following cases does managing vertical MRP placement become most important? (three correct answers) A. Low lens powers B. Made from CR-39 C. Aspheric or toric lenses D. Spheric lenses E. Made from Trivex F. High lens powers

C, E and F

True or False: Using a PD stick with the lower limbus or lid margin method is the most accurate way to determine the seg height of a bifocal

False - The most accurate way is subjective determination, either by marking a glazed lens, using transparent tape or by using Fresnel Press-On segments if available

True or false: You should NOT specify base curve on the prescription if you're ordering a second pair of lenses with identical power

False - Two pairs of glasses made with different base curves can end up distorting shapes in the patient's vision, best way to avoid this is to match the original frame's base curve as closely as possible, UNLESS the patient's base curve CHANGES after being examined

True or false: While the patient moving their head can induce errors in PD measurement, this does not occur when the examiner moves his or her head

False - both the patient's and the examiner's heads should be still and looking straight forwards when measuring PDs

True or false: The base curve for a multifocal lens can be a cylindrical curve

False - it is ALWAYS a sphere curve

True or false: Temple parallelism is checked with the frames placed on a table rightside-up

False - it is done upside-down so the temple bends don't influence the way the frame sits on the table

True or false: A lens clock is able to read the surface power of a fused bifocal segment

False - it only gives a reading for the distance portion

True or false: In the Ellerbrock equation, P stands for the distance PD

False - it's a variable that stand for HALF of the distance PD

True or false: When measuring PD from the limbus edge, measure from the temporal edge to the other temporal edge

False - measure from the temporal edge of one side to the NASAL edge of the other side

True or false: Like fused multifocals, one-piece multifocals are only made from glass

False - they can be made with ANY lens material

True or false: Essilor pupillometers can only measure distance PDs

False - they have settings that allow you to measure near PDs as well

True or false: Changing the base curve can get rid of 'ghost-image' issues

False - this simply moves them around, only AR coating gets rid of them (can be an option if AR coating isn't available)

True or false: You can only measure PDs with an Essilor pupillometer by lining up the Purkinje reflections off of the cornea

False - you can also line up the hairline with the pupillary centers (although the Purkinje reflections are preferred in most cases)

True or false: It is recommended to heat the frame when performing pantoscopic angling operations

False - you should AVOID this to prevent loosening the hinge rivets

True or false: Like with metal and plastic frames, bridge adjustments with rimless frames are done by holding the lens with your hands and adjusting with half-padded pliers

False - you should use a pair of rimless bracing pliers to reduce stress on the lens and keep it from breaking or coming loose

True or false: The further out an eye looks from the optical center of a high-index lens, the less evident chromatic aberrations become

False, they become MORE evident as you go further from the optical center

True or false: The frame should be fit as close to the eye as possible, even if the lashes rub against the lenses

False, you DON'T want the lashes rubbing up against the lenses

A frame is said to be out of vertical alignment if one of the lenses is [higher/further forwards or backwards] than the other

Further forwards or backwards

The first step in standard alignment is [this] and the last step is [this]

Horizontal alignment; temple fold angle

The preferred method of heating a frame is [hot air/salt beads]

Hot air (prevents frame materials and lens coatings from suffering damage)

For spherical lenses, the base curve is always the [front/back] surface curve

Front

A fused multifocal construction is made of [this material] only, and has a higher [this parameter] than the distance lens. There is also no [this landmark] or curvature change on the front

Glass; refractive index; ledge

The segments on cement multifocals are placed onto the lens this way

Glued on (typically small and round)

If a segmented multifocal lens is to be used for intermediate and near viewing only, the [this] power goes where [this] power would normally be found

Intermediate; distance

The ends of the temple should be bent not just at the same angle, but [outward/inward] slightly

Inward (to better fit the average head shape)

A frame with negative face form causes the nasal part of the eyewires to be [a great distance from the ruler/inward compared to the temporal eyewires]

Inward compared to the temporal eyewires

Near PDs, regardless of method obtained, should be [increased/reduced] with prescriptions with MINUS lenses

Increased (which reduces the inset of the add segment)

The distance decentered from the optical center to the MRP is called [this]

Inset

Hearing aids that sit behind the ear pair up best with temples that are [thick/thin]

Thin (preferably a cable temple, although thin enough skull temples in proper position will work too)

Raising the optical center of a MINUS lens makes the top [thinner/thicker] and the bottom [thinner/thicker]

Thinner; thicker

Patients should be instructed, to avoid misjudging distances from the eyes to the floor, to [do this with their heads]

Tilt their chin and head down while looking straight ahead

A patient complains to you that their bifocals are 'always in the way.' Is the segment too high or too low?

Too high

A patient complains to you that their bifocals are making their neck stiff from having to bend down all the time. Is the segment too high or too low?

Too low

The splay angle is viewed from the [top/front/side] of a frame

Top (or bottom)

The trifocal height is the [top line/near line] in the segment

Top line

For figuring out base curves, you always start out by putting the [front/back/total] lens power on the power cross no matter if you are working in plus or minus cylinder form

Total

The total distance between the center of the add and the optical center is called [this]

Total inset (add inset + seg inset to get total inset)

The [nominal/true] base curve is the curve measured using a lens measure or lens clock

True

Decreasing the vertex distance causes the segment height of a bifocal to appear to be [higher/lower]

Lower

Increasing the pantoscopic tilt of a frame causes the segment height of a bifocal to appear to be [higher/lower]

Lower

When viewing a frame from the side, an angle where the [upper/lower] rims of the frame front are closer to the face is called a 'pantoscopic' angle

Lower

A tall patient should typically have a [higher/lower/normal] segment, whereas a shorter patient should typically have a [higher/lower/normal] segment

Lower (because they look down a lot and their segment could get in the way; Normal (no adjustment is needed unless they're wearing double-seg lenses, which would probably have to be raised slightly)

For measuring trifocals using a PD stick, your reference point is at the (lower limbus/lower lid margin/lower pupil margin)

Lower pupil margin

A person typically walks around with their head tilted back with a straight posture. If they are prescribed bifocals, to make sure they aren't intrusive, the segment should be [raised/lowered]

Lowered (tilting your head back raises the segment, which can get in the way of distance vision)

Seg drop is the distance between [this point] and the top of the seg

Major Reference Point

If prism is prescribed, the eye is supposed to look through the [optical center/major reference point]

Major reference point

True or false - For patients with a constant strabismus, each eye will require a separate PD measurement, and one eye will end up with a much larger measurement

True

True or false: Dioptric demand is the inverse of the reading distance, not the add power

True

True or false: Four-point touch testing only ACTUALLY results in four points of contact if the frame is small in comparison to the head. If it is larger, face form is needed.

True

True or false: If a patient wants a pair of glasses just for reading, they will be prescribe a single-vision lens with no add power

True

True or false: If you see that the frame wobbles during a four-point touch test, it will sit on the face at an angle and needs to be adjusted

True

True or false: Modern rimless frames contain more than two holes for better stability

True

True or false: Monocular PDs should be taken using a pupillometer if possible

True

True or false: Most PD-measuring instruments have an occlusion system for monocular measurements

True

True or false: Moving both nosepads to the left will cause the frame to shift to the left on the face

True

True or false: One can use a shortcut to find the near PD before switching to their other eye for reading the distance PD

True

True or false: Quadrafocal lenses can only be made with glass material

True

True or false: With prewritten prescriptions, the working distance typically never exceeds the reciprocal of the near add power

True

True or false: You don't have to take lid thickness into account when measuring with a distometer - the instrument does that for you

True

True or false: The nominal power of a lens can be found using lens clock measurements for materials at or near an index of 1.53, simply by adding the front and back surface powers together

True (even with crown glass, but don't forget to account for cylinder if there is any on either surface)

True or false: You should rinse the lenses first before wiping them off with a cloth, unless that cloth is designed specifically for lenses

True (frames can also be washed using mild detergent)

True or false: Adding a trifocal to an existing bifocal height runs the risk of intruding into the pupillary area

True (in this case you would need to remeasure using the techniques listed on pages 72 and 73 of the textbook)

True or false: Near PDs don't typically give accurate seg heights if the difference between monocular PDs is very large

True (small differences are usually fine and can be ignored)

True or false: Temples that are spread too far in and temples that are spread too far out both share the characteristic problem of the frame sliding down the patient's nose

True (temples spread too far in also pull the backs of the ears when they do this, hurting the ears of the wearer)

True or false: If trying to find the nominal lens power of a high-index 1.65 lens, you can measure the front and back surfaces, add those together FIRST, and THEN multiply by the conversion factor to get the surface refractive power

True (this is called the 'Compensated Power Method')

True or false: You should specify base curve if you are replacing just one lens in a pair on a frame

True (to give the laboratory an idea of what the lens power was for the missing lens - you need BOTH powers to get an accurate prescription)

True or false: A near addition is essentially a small plus lens placed in the lower portion of the distance lens

True (which is why it is often referred to as the 'near segment' or 'seg')

True or false: With plastic frames, any adjustments made to correct horizontal alignment and the bridge area should be done by hand after heating the bridge, and usually don't require specific tools

True (with the exception being a rotated lens)

You should instruct the patient to remove their eyeglasses using [one/two] hands

Two

When adjusting for temple parallelism on a metal frame solely by using your hands, you want to be careful not to leave a [this letter]-shaped gap between the temple [this part] and the endpiece

V; butt

If a bifocal sits above the patient's lower limbus, the difference between the limbus and the seg height should be recorded as [positive/negative]

Positive

Name 2 advantages and 2 disadvantages of using 'readers' over bifocal adds or PALs

Possible advantages: - Wide field of near vision, perfect for those using extended reading/working tasks - Don't always require an Rx, can be bought OTC - Good for short adds, +1 to +3 usually - Cheap and affordable, wide range of colors and styles - Some have blue filters to block light from blue screens ('Computer Vision Syndrome') Possible disadvantages: - Can only see at near through these, going back and forth from distance to near would be better suited for multifocals - No cylinder prescription in OTC lenses - Anisometropes cannot wear OTC readers (different lens powers between eyes) - Optics may be of lower quality

Any point before the last 4 mm of a cable temple end should NOT do this

Press against the root of the ear

Is the 'moving your head' method for dispensers with visual impairment in one eye often preferred for PD measurement? Why or why not? If not, what other method could they use to measure PDs accurately?

No, because it induces parallax errors - to prevent this the dispenser should use a monocular measuring instrument such as a pupillometer

The [nominal/true] base curve results from the lens manufacturers changing the front surface of the lens slightly to account for increased lens thickness and maintain the initial prescription

Nominal

A person typically walks while slightly hunched over, with their head tilted slightly upwards. If they are prescribed bifocals, the segment CAN be [raised/lowered]

Raised (makes it easier for them to see through it and do near work)

To prevent the upper segment of a double-seg lens from intruding on distance vision, the lower segment must be [raised/lowered]

Raised (there is always a 13-14 mm difference between the two lenses when they are made, ergo pushing one up pushes the other up)

This type of specialized bifocal segment is also referred to as the 'minus add' segment

Rede-Rite

Once you take binocular PDs, before moving the ruler, the scale reading at the center of the subject's nose corresponds to their (right/left) monocular PD

Right

The dispenser begins distance PD measurement by closing their (right/left) eye and sights with their (right/left) eye

Right; left

You want to use a [rough/small] file when filing the butt end of the temple to reduce temple spread

Rough

If you want a bifocal segment that can be placed at unusual positions on the lens, which bifocal segment is your best bet?

Round bifocal segments

'Blended' bifocals are typically [flat-top/rounded] and work better with [lower/higher]-powered lenses

Rounded; lower

The base curve of a segmented multifocal lens is always on the [same/opposite] side of the curve with the segment on it

Same

The splay angle of a pair of plastic frames with a fixed angle bridge can be modified by heating the pads (with air or hot salt) and bending them outward using [this kind of] object

Smooth and flat object

Positioning of the temple bend is incomplete if the bent-down part of the end [digs into/stands away from] the side of the head

Stands away from

If using a salt pan to heat a frame, always [do this] before inserting the frame

Stir the salt with a spoon to equalize the heat

Define: X-ing

When the front of the frame is twisted and the planes of both lenses are out of alignment with one another, resulting in an 'x' shape when viewed from the side

To make sure the intermediate of a trifocal does not impede distance vision, what do you do to the seg height after measuring?

Take off a millimeter

The distance the segment is decentered from the MRP to the center of the add is called [this]

Seg inset

Near PDs, regardless of method obtained, should be [increased/reduced] with prescriptions with PLUS lenses

Decreased (segment inset increased)

Fresnel lenses for double-seg bifocals should be [this many diopters] less than the power of the new bifocal add

0.50 D

What type of frame tilt is this, and when is it appropriate to be used?

- Positive face form tilt - When the wearer's PD is less than the 'frame PD' (eye size + bridge size)

One-piece multifocals, unlike fused multifocals, have one of these

Ledge (it can be felt by feeling around the segment border)

Between which three anterior eye landmarks can you possibly measure PD from on the average adult?

- Pupil center to pupil center - Left pupil edge to left pupil edge - Left limbus edge to left limbus edge

The three-quarters rule states that for every one diopter of demand needed at near, the optical center of the lens/geometric center of bifocal adds should be displaced inwards by [this number] millimeters (Hint: why is it called the 'three-quarters' rule?)

0.75

For every three diopters of vertical prism prescribed, the seg height should be displaced about [this many] millimeters (to the nearest tenth)

0.9 mm

Rotated lenses are corrected using [these types of] pliers

Lens rotating pliers (with the flat bottoms)

The end of a cable temple should be bent [forward/back] and slightly [towards/away from] the side of the head

- Back - Away from

Trifocals usually aren't available below powers of [this many diopters] of add

+1.50 D (Patients usually have a large enough Zone of Clear Singular Binocular Vision within this range that an intermediate add isn't necessary)

The first method of changing the temple fold angle uses [these] pliers; the second method uses [these] pliers

- Angling pliers (without head since the hinges are usually metallic) - Finger-piece pliers

Which of these types of bifocals is smaller in length, a B-segment or R-segment ribbon? What is the practicality of using this segment over other segments?

- B-segment - Allows patients to see distance below the segment, as if looking down off of a high structure like a construction worker

If the right lens is sitting too low, you can either bend the right temple [upwards/downwards] or bend the left temple [upwards/downwards]

- Downwards - Upwards

What type of trifocal is this? It's actually made up of two other near add types - can you name them?

- E/D trifocal - Executive and Flat Top (called 'D' because it looks like a sideways 'D')

If the patient has to take their glasses off with one hand, tell them to grasp near the [shaft/endpiece] and move the glasses to the [same/opposite] side of the face from the hand that takes them off

- Endpiece - Opposite

Temple parallelism may be off if: - The [this frame part] isn't straight - The [this part of the temple] is bent - [This part] of the frame is slightly twisted - [These parts] are loose or broken - [These parts] may need to be straightened

- Endpiece - Temple shaft - Bridge (should've been fixed already by correcting X-ing) - Hinge rivets - Hinge itself

What type of bifocal segment is this? (assume the top right and left corners are sharp, not round) Where is the optical center of this segment? What's the most common size they come in?

- Flat-top bifocal segment - On the top line in the center - At least 28 mm

What type of trifocal is this? The dimension of this particular trifocal is 7 x 28. What does the first number mean? The second number?

- Flat-top trifocal - Depth of the intermediate add - Width of the segment (NOT the depth of the near add)

What are the two names of this type of bifocal segment? What happens to the 'ledge' atop the segment as add power increases?

- Franklin or Executive segment - Thickness increases

For spherocylinder lenses in minus form, the base curve is the [front/back] surface, which is [spherical/cylindrical]

- Front - Spherical

For spherocylinder lenses in plus form, the base curve is one of the curves on the [front/back], specifically the [strongest/weakest] curve in terms of base power. The other curve is called [this type of] curve

- Front - Weaker - Cross

The nosepad angle most clearly viewed from the front is the [frontal/splay/vertical] angle (it's not a trick question). It is commonly placed at [20/25-30/15] degrees from the eyewire

- Frontal - 20

In the sagittal depth formula, r = ((y^2)/2s) + (s/2), y is [the chord length/half the chord length] and s is [this]

- Half the chord length - Sagittal depth

To assist with correcting temple parallelism, grasp the endpiece with [these] pliers and grip atop the hinge with [these] pliers

- Half-padded - Angling (looks like a clamp)

The 'A' size change rule of thumb doesn't necessarily work in two instances: - The bridge is adjusted [this way] - The wearer's cheeks cause the lower eyewire to do [this]

- Higher or lower than it was in the frame, causing inconsistencies in size variations - Sit in a different part of the face, which can cause the frame to rest higher or lower)

To increase the vertex distance and the height of a frame at the same time, you [do this] to the nosepads, or [this] to the bridge

- Narrow the distance between them, for both

What type of frame tilt is this, and should you use it to correct large PDs?

- Negative face form tilt - No, it's cosmetically unattractive

'Nominal base curve' and 'nominal lens power' are two different things - describe each term

- Nominal base curve: Base curve that is modified slightly by manufacturers to maintain overall prescription and account for lens thickness - Nominal lens power: Summation of front and back surface powers from lens clock measures

What kind of tilt is this, and when is it appropriate to use?

- Pantoscopic tilt - If the patient's eyes are above the optical center of the lenses

What kind of tilt is this, and when is it appropriate to use?

- Retroscopic tilt - Not practical for use, since it is not cosmetically attractive

Assuming this bifocal segment is the SHORTER type, what type of bifocal segment is this? What material is it made out of?

- Ribbon B-segment - Glass only

Assuming this bifocal segment is the LARGER type, what type of bifocal segment is this? Where is its optical center?

- Ribbon R-segment - In the middle of the segment

What type of bifocal segment is this? What's the most common size they come in?

- Round segment - 22 mm

When removing cable temple spectacles from their heads, patients should be advised to have one hand hold [this area] and the other hand grasp and pull [this area] around the ear

- The frame front (near the endpiece) - The other side's temple end/tip

If the temples aren't spread out far enough, you can try these three things: - Make sure [this] is completely in the frame - [Pull/push] the endpiece with your fingers after heating it - If they come in a lot, you can [do this to] the butt end of the temple

- The lens - Pull - File

The gist of the Stimson triangle diagram is that the frame should only be touching the patient's head at [this many] points. The points at the [nose/ears] are the 'pressure' points

- Three - Ears

The [frontal/splay/vertical] angle is most crucial for proper weight distribution underneath a nose pad. For a frame with pantoscopic tilt, the bottoms should be [closer to/further from] the frame front than the tops

- Vertical - Closer to

For spherocylinder lenses in minus form, the two back curves are called the toric base curve and the cross curve. The toric base curve is the [stronger/weaker] of the two. Opticians call this curve something different, [this]

- Weaker - Back base curve

The distance from the face of a nosepad from the eyewire should be about [1/2/4] mm when viewed from the front

1 mm

A lens blank is 'finished' if [all of its powers/one of its powers/none of its powers] match the final prescription

All of its powers

A prescription calls for 4 diopters of base down prism. How much should the seg height be shifted, and in what direction?

1.2 diopters, upwards (towards the apex, so it will be raised up)

A patient with a prescription of lenses wants a pair for intermediate and near viewing, but not for distance viewing. The add on their current pair is +3.00 D. Assuming a normal intermediate power is 50% of the near add, how much would you add to the current distance power to get the new 'distance' lens power for the intermediate glasses?

1.50 (50% of 3.00 is 1.50)

A patient needs a bifocal for reading at 33 cm. The add power recommended to them is +2.00. What should the inset be per lens?

2.25 mm (1/0.33 = 3, 3 x 0.75 = 2.25, IGNORE the add power)

When fitting progressive addition lenses on children, the fitting cross is placed [here]

4 mm above the pupil center

A patient has a measured distance PD of 66 mm. Their prescription is +4.00 D. They work at a near distance of 20 cm, and the lenses are about 30 mm from the center of rotation of the eye to the back of the lens. What is the segment inset? (Use Ellerbrock's formula and round to the nearest tenth of a millimeter)

4.8 mm (P = 66/2 = 33; w = 200 mm [20 cm = 200 mm] s = 30 mm, 1/30 = 0.03333 f = 1/4 = 25 cm = 250 mm, 1/250 = 0.004 (33)/(1+200(0.03333-0.004)) = 4.8 mm)

The dispenser should be positioned this far from the patient when measuring PDs, in centimeters

40 cm (16 inches)

When calculating the near PD using similar triangles, which of the following locations signifies where the points go? (two correct answers) A. Center of rotation of both eyes B. Optical center of both eyes C. Near point of fixation D. Bridge of the nose

A and C

By 'bring in' a temple, the book means 'change [this parameter] of the frame' A. Temple spread B. Temple straightness C. Bridge position

A

Which variation of the lensmaker's equation, (n-n')/r, is used for the back surface of a lens? a. n=1 b. n'=1 c. Neither

A (back surface power should be negative for meniscus lens hence the lower refractive index, for most cases 1, should go first)

A one diopter increase in base curve depth corresponds to a vertex distance change of approximately [this many] millimeters A. 0.6 B. 0.8 C. 1.0 D. 1.2

A (it also depends on how big the lens is though)

Ellerbrock's formula is typically only used when: A. Distance powers are very high B. Distance powers are low C. Working distance is less than 40 cm D. It's always the preferred method of finding seg inset

A (it's cumbersome to work with using other methods, you're better off measuring or using Gerstman's 3/4 rule if their PD is within 62-68 mm)

Fitting of frames starts with a different step than standard alignment, that of working with the: A. Temple spread angle B. Open temple angle C. Horizontal alignment D. Nosepad adjustment

A (prevents too much pressure from being exerted onto the head, and prevents the glasses from falling off the wearer when they look down)

The best lens materials for a rimless mounting are (select two): A. Polycarbonate B. CR-39 C. Crown glass D. Trivex

A and D

With executive or Franklin segments, you want to avoid prescribing them to patients with large [these boxing metrics] (two answers) A. A sizes B. B sizes C. C sizes D. DBL sizes E. ED sizes

A and E (makes the lens weightier and more awkward, better off using a large flat-top segment)

Telling the lab to make a flatter base curve can introduce more of [these defects] in the lens periphery due to the base curve not matching the lens power

Aberrations

Frames should only exert pressure at two points, one per each side of the head, at [this area near the ear]

Above the root of each ear

Define: Distometer

An instrument used to measure the vertex distance of a worn frame

During initial alignment the vertical angle should be about [this many] degrees: A. 10 B. 15 C. 20 D. 5

B

To simulate normal working conditions for measuring a bifocal height, have the wearer do this A. Look down B. Hold something near their working distance and look at it C. Hold something closer than their working distance and look at it

B

Trifocals with a depth of more than [this many] millimeters should not be considered an all-time-wear lens A. 10 B. 8 C. 4 D. 5 E. 12

B

You wish to check seg heights for a frame, but this frame has no lenses in it. You can instead use [this] to simulate the bifocal segment A. A new pair of lenses slotted in B. Transparent tape C. Fresnel Press-On segments D. A PD ruler set horizontally

B

The first step in checking temple spread is to make sure that: A. The endpiece is heated B. The temple shafts are straightened C. The endpiece is bent so the temples make a 94-95 degree spread

B (provides a more accurate overall temple spread)

Calculated PDs are preferred for high-powered lenses rather than measured PDs because of their tendency to: A. Be astigmatic B. Induce prismatic effects C. Present with amblyopia D. Present with a strabismus

B (typically Ellerbrock is used to find the appropriate segment inset for these, which is then used to find near PDs by rearrangement of the initial seg inset equation)

When fitting seg heights on children, they should be placed so that they [do this] to the pupil

Bisect it

Salt pans should be avoided when using [this color] frame to avoid visible indentations and 'dulling' of the hue of the frame

Black frames

Widening the bridge of a plastic frame requires this tool

Bridge-widening pliers (there are also bridge-narrowing pliers)

If you go to measure a patient's PDs, but find they are strabismic, what can you do to continue and find an acceptable reading?

Cover the patient's eye that isn't being observed - when they look at your left eye, have them cover their left eye and vice versa

If the dispenser cannot close just one of his eyes to measure PDs without closing the other, they can work around this by...

Covering that eye with their free hand

Define: Base curve

Curve that serves as a starting point from which other curves are determined

What type of bifocal segment is this? (there are distinct points)

Curve-top

Gerstman's three-quarters rule applies for patients with a PD between [this number] and [this number] millimeters. A. 60 and 64 B. 62 and 66 C. 64 and 70 D. 62 and 68

D

Progressive addition lenses use [this landmark] as a reference point for seg height: A. Lower edge of the pupil B. Lower limbus C. Upper edge of the pupil D. Center of the pupil

D

The normal pantoscopic angle varies from anywhere between [this many] to [this many] degrees: A. 2-8 B. 4-8 C. 6-12 D. 4-18 E. 2-22

D

Large cable temples have a tendency to [do this to] the lower earlobe

Dig into

Define: Image jump

Displacement of the apparent image of an object when transitioning from distance to near segments due to the higher prismatic effects (can be calculated with Prentice's Rule, cF = pd, with 'c' being the distance from the upper bifocal border to the optical center of the segment)

Segment inset is half of the difference between which two parameters?

Distance PD and near PD

A monocentric bifocal is one where [these two landmarks] occupy the same spot on the lens

Distance and segment optical centers

With plastic frames, in adjusting the bridge you can use your hands. To assist with this process on metal frames, which may be either more delicate or more resistant to movement, you can use [these] pliers

Double-padded pliers

A patient spends more time outdoors than they do indoors, but still needs a bifocal for occasional near viewing. Compared to a person who works at a desk, typically they should have their seg height adjusted [upwards/downwards]

Downwards (since they don't use them as often)

To increase the vertex distance without changing the height of the frame, increase [this property] on the nosepads

Effective length (bring them away from the eyewire, decreasing them brings the vertex distance down)

If a frame has face-form tilt, when checking for four-point touch, make sure the nasal eyewires are [this] from the ruler

Equidistant (same length away)

Avoid steepening the base curve to try and give more clearance for a patient's [these facial features]

Eyelashes

True or false: You can physically feel a fused segment on a multifocal lens

False (they're fused into the distance part, hence the name)

True or false: The customary near working distance is usually assumed to be 40 cm, regardless of the add power

False - It's 40 cm UNLESS the add power EXCEEDS +2.50 D, then it becomes the reciprocal of that add power (i.e. +4.00 D = 25 cm)

If a dispenser is visually-impaired in one eye, they can still measure PDs by...

First lining up their good eye in front of the patient's right eye, lining up the zero mark, then moving in front of the patient's left eye and reading off the PD

For the following situations, state if the frame bridge should be narrowed or widened for maximum comfort: - Frame sits too high up - PAL cross heights are too high up - Lenses are too far away - Lashes rub against the back surface of the lens - Bifocal/trifocal segments are too low to be seen out of

First three are fixed by widening the bridge Last two are fixed by narrowing the bridge

You are measuring monocular PDs and you finished marking the pupil centers in each eye. What do you do next?

Go back and check to make sure the crosses are centered (patient's right by opening your left eye, patient's left by opening your right eye) and if they aren't, start over. If they are, measure the distance between the crosses using a ruler

Small cable temples don't have the necessary [this] to keep the frame stable on the head and the ear

Grip

You should secure the butt portion of the temple near the hinge with [these] pliers if you want to reduce the temple spread angle

Half-padded (be careful, this method can cosmetically damage the frames)

When making changes to Optyl temples, you MUST remember to do this

Heat the frame (otherwise it will easily break)

Which lenses induce more chromatic aberrations, crown glass lenses or high index lenses? How does this pertain to measuring a patient's monocular PDs?

High index lenses; the further off the patient's eye is from the optical center, the more of these aberrations they'll experience and the higher negative impact it will have on their vision

A frame is said to be out of horizontal alignment if one of the lenses is [higher/further forwards or backwards] than the other

Higher

For high-plus lenses, seg heights should be placed [higher/lower] to reduce aberrations

Higher

Skewed bridges causes one lens to appear [higher/further back] than the other

Higher

Round segments are usually placed about 1 mm [higher/lower] than flat-top segments

Higher (Upper area isn't used as much, and their OCs are further down from the top of the segment, which is where the patient should be looking)

Vertex distance changes are more important in patients with [lower/higher]-powered prescriptions since they induce changes in [spherical/cylindrical/both spherical and cylindrical] lens powers

Higher; both spherical and cylindrical

Rimless bracing pliers

Holds rimless eyewear at the point of lens attachment.

The PD rule should be tilted on the subject's nose so that the scale sits where?

In the most recessed area

At the optical center of the lens, there [is some/is no] prismatic effect

Is no

You may need to use a different frame or lower the pantoscopic tilt if you have a very [small/large] pantoscopic angle

Large

If a lens won't cut out because the wearer's PD is too small to permit lens decentration, the frame might be too [small/large] for the wearer

Large (confirmed by moving the frame left or right to show what the near PD should be so it will cut out properly)

Patients should be informed that objects viewed through their new adds could appear [larger/smaller] than normal

Larger (plus lenses induce magnification)

Raising the optical center of a PLUS lens makes the top [thinner/thicker] and sometimes [increases/decreases] the center thickness

Thicker; increases

The base direction for MINUS lenses is towards the [center/margin] of the lens

Margin

Does the patient need to shift their gaze when measuring their near PDs using a PD ruler?

No (nor does the dispenser need to switch eyes)

MRPs are placed according to the [monocular/binocular] PDs if the wearer's eyes differ in distance from the bridge of the nose

Monocular

If a lens won't 'cut out' because the segment is too high or too low, what can you do to ensure the lens will be cut out?

Move the frame up and down until the drawn lens covers the frame's 'lens opening,' which shows you how much the seg height needs to be raised or lowered so it will properly cut out

Rede-Rite

Name the type of occupational bifocal seen here

A dowel rod with a size of 3/8 of an inch is effective for [narrowing/widening] a heated plastic bridge

Narrowing (widening requires a 5/8 inch wide rod)

The only time you would ever consider moving the MRP height below the 'datum line,' or horizontal midline of a pair of glasses, is if the lenses are used for [this activity]

Near reading/work

In the average eye, corneal reflection usually occurs towards the (temples/nose)

Nose (1.6 degree angle variation)

Measuring monocular PDs with a ruler alone doesn't always work because it relies on the patient having a symmetrical [this], which is not always the case

Nose (especially if it has been broken recently or had surgery)

In order to determine MRP height without using the 2 for 1 rule, have the patient fixate [here] and tilt their chin upwards until the frame front is [this] with the floor before marking the pupil centers and measuring from the lower eyewire

On the bridge of the nose; perpendicular

Rule of thumb for improper 'A' size between frames states that for every two millimeters of 'A' size displacement, the seg height should be displaced by [this many] millimeters

One

Anatomic PD is a measure from...

One eye's pupillary center to the other eye's pupillary center

A lens blank is 'semifinished' if [all of its powers/one of its powers/none of its powers] match the final prescription

One of its powers (typically the front side)

All plastic add segments are made as [this type of multifocal]

One-piece multifocals

Normally when spectacles are made, the lenses are positioned so that [this lens landmark] lines up with the pupil of the eye.

Optical center

What type of bifocal segment is this? (the corners are NOT distinct or pointy)

Panoptik

Before measuring PDs, it is noted that the dispenser's PD is much larger than that of the patient's PD. What type of error does this induce?

Parallax error, resulting in slightly larger PD measurements

To mark corneal reflections outside of a pupillometer, this tool is needed

Pen light

Screwdrivers made to tighten or loosen rimless lens screws typically have [one of these] to prevent it from slipping and damaging the lens

Plastic sleeve

Define: Major Reference Point

Point on the lens where the prismatic effect equals the prism amount prescribed

Corneal reflections lie on the (line of sight/pupillary axis)

Pupillary axis

Why do we take PD measurements, anyways?

So we can effectively line up the optical centers of each lens with the patient's eyes so no prismatic effects occur, which could lead to fixation errors down the road

For children who aren't cooperative, you can measure their PDs between these structures

Temporal canthus of one side to nasal canthus of the other side (not an exact measure since inner canthi stretch further across the sclera)

A correct length cable temple should stop just short of [this part] of the ear

The lower lobe

If there is no prism, where is the MRP in relation to the optical center?

They coincide at the same point on the lens

A crooked frame can result in [this error] in seg height

Unequal seg heights

When viewing a frame from the side, an angle where the [upper/lower] rims of the frame front are closer to the face is called a 'retroscopic' angle

Upper

If a lens gets rotated in the frame, one of the eyewires appears [upswept/downswept]

Upswept

If an eye tends to turn downward, you would prescribe a prism with the base direction [upwards/downwards]

Upwards

To move a nosepad up and down, you pull upwards/downwards with slight force and move the nosepad as if you're changing the [frontal/splay/vertical] angle

Vertical

If you cannot find a suitable position for the trifocal in a frame, you need to use a frame with a greater [this]

Vertical depth

- Double-segment bifocal - 13-14 mm - Quadrafocal

What kind of occupational multifocal is this? How large is the distance between each segment on this lens? If the bottom segment was a trifocal segment, what would that type of multifocal be called?

The dispenser puts themselves at the subject's [this] when checking for their near PD

Working distance

Subjective determination with a glazed lens for trifocals is similar to bifocals, except you draw in what and do what with it?

You draw the two trifocal lines (lower trifocal line placement doesn't matter too much as long as it's within reason) and fill in the gap with the marking pen, the tinted area acting as the 'intermediate' area

You use [this] file to file plastic parts of a frame, and [this] file to file metal parts of a frame

Zyl; Pillar