Unit 2 - Progressive Addition Lenses Flashcards
A progressive lens design with a gradual increase in unwanted astigmatism is considered a ______ design.
a. soft
b. hard
c. swimmy
d. dynamic
a. soft
Which of the following shaped frames should be avoided when PAL are used?
a. square
b. round
c. pilot
d. all the above
c. pilot
When determining the fitting cross height for a PAL patient, you should measure from the deepest point on the plane to the _____.
a. lower limbus
b. center of pupil
c. lower edge of pupil minus 1 mm
d. upper limbus
b. center of the pupil
When checking the distance power of a PAL, the _____ side of the lens should face the operator.
a. convex
b. concave
c. convex for plus lenses and concave for minus lenses
d. concave for plus lenses and convex for minus lenses
a. convex
If the patient must lower their head to see clearly in the distance, the lenses are positioned too high.
a. true
b. false
a. true
If a patient must move the reading material to the side to see clearly, the pupillary measurements may be off.
a. true
b. false
s. true
When fitting a frame to a PAL patient, _____ degrees of pantoscopic tilt is recommended.
a. 2-6
b. 6-8
c. 10-12
d. 15-20
c. 10-12
______ will effectively increase the intermediate and near viewing zones for a PAL.
a. Shorter vertex distances
b. Less pantoscopic tilt
c. Frames with large nasal cuts
d. Reduced fitting cross heights
a. Shorter vertex distances
Free form machining can create _____ surfaces.
a. aspheric
b. atoric
c. progressive
d. all the above
d. all the above
The amount of prism used in prism thinning is equal to ____ of the add power.
2/3 (two-thirds)
Which is better for new presbyopes - soft or hard PAL designs?
soft
Varilux made by Essilor was the very first progressive lens marketed to the world.
a. true
b. false
a. true
Asymmetrical PALs push the majority of the astigmatism to the _____ side of the lens.
a. temporal
b. nasal
c. convex
d. concave
b. nasal
What is the minimum fitting height for today’s short-corridor PALs?
a. 12 mm
b. 15 mm
c. 18 mm
d. 22 mm
b. 15 mm
True or false.
We can use a specialized PAL to help people in different lines of work.
true
Which 5 things do we measure when fitting a patient for a PAL the traditional way?
- distance PD (mono)
- near PD (mono)
- fitting cross height (mono)
- vertex distance
- pantoscopic tilt
What do we do with the patient’s frame before we even take the measurements?
Fit the specs to the patient’s face perfectly (vertex distance, panto tilt, nosepads, temples, etc.)
What is head cape?
Head cape is the measurement of the natural resting position of the head.
A frame works well for a PAL patient if their fitting cross height (where it bisects their pupil) is ____ to ____ mm.
18-24
What do we do after we measure the patient for the PAL?
Check the marked measurements on the lenses against the manufacturer’s layout chart to ensure it satisfies their requirements.
What 3 things do we check for in the PAL distance circle?
- sphere power
- cylinder power
- axis
We can find the _____ on the nasal side.
a. add power
b. brand
c. PRP
d. power value
b. brand
We can find the _____ on the temporal side.
a. add power
b. brand
c. PRP
d. fitting cross
a. add power
You can find the add power engraved below the 180 line on the _____ side of the lens.
temporal
What 3 things do we verify on the manufacturer’s cut out chart?
- mono distance PD
- horizontal prism, if ordered
- fitting height
True or false.
We will likely find some type of vertical prism in most lenses due to the common practice of prism thinning.
true
