Term
When light enters the eye, what ocular structure does it interact with first? |
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Definition
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Term
Approximately how much power can be generated by the eye’s optical system? |
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Definition
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Term
An eye that focuses light rays in front of the retina instead of the retina is called
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Definition
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Term
+2.25D is an example of what type of prescription? |
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Definition
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Term
A convex lens will correct which type of refractive condition? |
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Definition
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Term
An eye that focuses light rays in more than one spot on the retina has.... |
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Definition
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Term
-3.50 -1.00 x 189 is an example of what type of astigmatism? |
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Definition
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Term
+0.50 -1.00 x 180 is an example of what type of astigmatism? |
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Definition
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Term
+2.50 -1.00 x 180 is an example of what type of astigmatism? |
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Definition
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Term
One meter is closest to which of of the following measurements?
1 inch
1 foot
1 cm
1 yard |
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Definition
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Term
1 meter equals how many cm and mm? |
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Definition
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Term
Wave lengths are measured in? |
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Definition
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Term
Wavelengths seen by the human eye are between how many nanometers? |
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Definition
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Term
Which color on the visible spectrum most contributes to blurry vision? |
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Definition
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Term
The angle at which incoming light rays strike a surface is called the... |
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Definition
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Term
The angle at which light rays leaves a reflecting surface is called the.... |
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Definition
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Term
When light rays enter a glass with parallel sides at a perpendicular angle it will... |
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Definition
Slow down the light rays, but not change the angle |
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Term
The formula used to calculate the angle of refraction is |
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Definition
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Term
Which of the following refers to the right eye?
Left eye
OS
OD
OU |
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Definition
Right - OD
Left - OS
Both - OU |
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Term
The following Rx represents what type of correction?
Rx -3.00 Sphere |
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Definition
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Term
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Definition
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Term
What is the next dioptric step in the following list?
0.00d, 0.12d. 0.25d, 0.37d, 0.50d |
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Definition
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Term
Axis readings may be between: |
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Definition
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Term
If the Rx has the notation 'PAL' it means? |
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Definition
the patient is presbyopic |
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Term
The common Trifocal power is: |
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Definition
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Term
If the front curve of a lens is +5.00 and the back curve is -3.00 the power of the lens is |
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Definition
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Term
If the front curve of a lens is +4.00d and the back curve is -5.00d, the power of the lens is |
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Definition
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Term
Transpose the following Rx:
-2.50 +1.25 x 90 |
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Definition
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Term
in what direction is light directed when it passes through a prism? |
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Definition
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Term
What instrument measures the vertex distance? |
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Definition
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Term
What influences how much an image is displaced when looking through a prism? |
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Definition
Strength of the prism
How far the prism is being held from the object being viewed |
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Term
What is the power of a prism that didsplaces light 1 cm at a distance of 1 meter? |
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Definition
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Term
What is the power of a prism that displaces light 1 cm at a distance of 0.25 meters? |
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Definition
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Term
What is the focal length of a +4.00d lens? |
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Definition
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Term
What is the power of a lens with a virtual 4m focal length? |
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Definition
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Term
High plus lenses create a peripheral distortion that causes objects to appear in what shape? |
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Definition
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Term
Which of the following is not a type of abberation that is created with an incorrect base curve choice?
Marginal
spherical
distortion
circular |
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Definition
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Term
Which abberation type is created when light rays hit a spherical surface at an angle, leading to the creation of the corrected curve lens series?
Marginal
Spherical
Distortion
Circular |
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Definition
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Term
'Barrel' distortion is created by which lens type? |
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Definition
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Term
the Corrected Curve Theory is based on correcting errors when the patient looks how far away from the optical center? |
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Definition
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Term
Generally speaking, base curves for minus power lenses will fall into what range? |
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Definition
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Term
Generally speaking, base curves for plus power lenses will fall into what range? |
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Definition
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Term
According to ANSI standards, when requesting a base curve, it must be within what parameters in order to meet the requirements? |
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Definition
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Term
If the front curve is +3.00d and the back curve is -4.00d what is the total power of the lens? |
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Definition
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Term
'Pincushion' distortion of created by what lens type?
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Definition
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Term
The point through which light rays pass without being refracted is called the.... |
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Definition
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Term
When the optical centers of a plus lens are wider than the patient's PD, which type of prism is induced?
Base down
Base in
Base up
Base out |
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Definition
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Term
When the optical centers of a minus lens are wider than the patient's PD, what type of prism is induced?
(base in/out/up/down) |
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Definition
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Term
When the optical centers of a minus lens are narrower than the patient's PD, which type of prism is induced?
(Base in/out/up/down) |
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Definition
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Term
When the optical center of a plus lens are narrower than the patient's PD, what type of prism is induced?
(Base in/out/up/down) |
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Definition
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Term
Calculate the total amount of prism induced in the following patients situation:
PD: 60mm
Optical Centers: 64mm
Lens Power: - 2.25d OU |
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Definition
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Term
Calculate the total amount of prism induced in the following patients situation:
PD: 66mm
Optical Centers: 58mm
Lens Power: 22.50 OU |
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Definition
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Term
Calculate the total amount of prism induced in the following patient situation:
PD: OD 29mm
Optical Centers: OD 31mm
Lens Power: OD +3.00d
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Definition
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Term
Which situations result in a canceling of the induced prism? |
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Definition
Base in and base out
base up and base up
base down and base down |
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Term
Which situations results in a compounding of the induced prism? |
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Definition
base in and base in
base out and base out
base down and base up |
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Term
Which of the following is a characteristic of a plus lens?
Minify objects
Virtual focal length
'Against' motion movement
'With' motion movement |
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Definition
"Against" motion movement |
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Term
Which of the following is a characteristic of a minus lens?
Effective power becomes stronger as the lens is moved closer to the eye
Effective power becomes weaker as the lens is moved closer to the eye
'Against' motion movement
Lenses have a real focal length |
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Definition
Effective power becomes stronger as the lens is moved closer to the eye |
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Term
Which of the following will usually not require a change in the base curve between a patients previous and new eyewear?
Change to aspheric design
Significant Rx change
Lens tint
Change in lens material |
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Definition
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Term
In the following Rx, what are the two values on the optical Cross?
Rx -3.00 -1.50 x 180 |
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Definition
-3.00 @ 180 and -4.50 @ 90 |
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Term
In the following Rx, what are the two values on the optical cross?
Rx: -1.00 -2.50 x 180 |
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Definition
-1.00 @ 180 and -3.50 @ 90 |
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Term
In the following Rx, what are the two values on the optical cross?
Rx: +2.00 -1.00 x 180 |
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Definition
+2.00 @ 180 and +1.00 @ 90 |
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Term
In the following Rx, what are the two values on the optical cross?
Rx: -2.50 + 1.00 x 90 |
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Definition
-2.50 @ 90 and -1.50 @ 180 |
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Term
Calculate the amount of prism induced in the following patient situation:
PD 58mm
Optical Center 62mm
Lens power: -1.50 -1.50 x 180 OU |
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Definition
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Term
Calculate the amount of prism induced in the following patient situation:
PD: OD 30mm
Optical Center: OD 28mm
Lens Power: OD -1.00 -2.50 x 90
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Definition
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Term
Calculate the amount of prism induced in the following patient situation:
PD: 30mm OU
Optical Center: 28mm OU
Lens Power: OD +2.00 +0.50 x 180
OS + 1.50 +1.00 x 45 |
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Definition
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Term
The well placed optical center should be approximately how far below the pupil vertically? |
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Definition
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Term
If a presbyopic patient has significant difference in power between his two eyes, which of the following are not required to balance the images when reading through the bifocals:
Bicentric Grinding, Image dispersion, Additional prism, Slab off |
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Definition
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Term
Calculate the amount of prism induced in the following patient situation:
Lens Power -2.00 -0.50 x 180
Patient reads 5 mm below optical center |
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Definition
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Term
Which of the following is a true statement regarding plus spherical lenses?
They are thicker in the center, converge light and minify objects
They are thicker in the center, diverge light and minify objects
They are thinner in the center, converge light and minify objects
They are thicker in the center, converge light and magnify objects |
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Definition
They are thicker in the center, converge light and magnify objects |
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Term
Which of the following is a true statement regarding minus spherical lenses?
They are thinner in the center, diverge light and magnify objects
They are thinner in the center, diverge light and minify objects
They are thinner in the center, converge light and magnify objects
They are thicker in the center, converge light and minify objects |
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Definition
They are thinner in the center, diverge light and minify objects |
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Term
If a high minus lens needs to be decentered in the frame, it will most likely result in:
Thin edge temporally
More thickness nasally
More thickness temporally
A thin edge superiorly |
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Definition
more thickness temporally |
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Term
If a high plus lens needs to be decentered in the frame it will most likely result in:
More thickness temporally
More thickness nasally
A Thick edge inferiorly
A thick edge superiorly
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Definition
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Term
Which of the following is not an advantage of aspheric lenses vs spherical lenses
Improved appearance of higher lens power
Reduced lens thickness & weight
Improved optics in higher powers
Decreased peripherial distortion |
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Definition
Decreased peripheral distortion |
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Term
Which of the following is not a common name used to describe a flat top bifocal?
Straight Top
Kryptok
D segment
Half moon |
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Definition
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Term
Bifocal segments are recommended to be fit: |
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Definition
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Term
Trifocal segments are recommended to be fit: |
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Definition
At the lower pupil margin |
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Term
PALs are recommended to be fit: |
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Definition
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Term
Computer glasses have segments for: |
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Definition
Intermediate and near vision |
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Term
The material characteristic that describes it's ability to bend light is called: |
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Definition
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Term
The material characteristic that describes its density is called: |
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Definition
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Term
The material characteristic that describes its chromatic abberation is called: |
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Definition
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Term
The material characteristic that describes how much light can pass through it is called: |
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Definition
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Term
Which of the following is the most impact resistant material listed?
Glass/CR-39/Polycarbonate/Plastic |
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Definition
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Term
Which of the following materials is least impack resistant material listed?
Glass/CR-39/Polycarbonate/Plastic |
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Definition
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Term
When a material has a high index of refraction it: |
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Definition
Shows it has a greater ability to bend light |
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Term
When a material has a high specific gravity, it means it: |
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Definition
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Term
When a material has a low ABBE value, it means that it: |
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Definition
Has more chromatic abberation |
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Term
Children, patients with good vision in one eye only, active in sports and who's job may pose a danger to the eyes should consider what material? |
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Definition
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