Optics Dispensing Exam Questions And
Answers 100% Verified.
Lens factors which effects quality of vision - correct answer. Optical abberations
Reflectance (about 9% from both surfaces, no arc)
Light scattering
Lens factors such as low order abberations can be eliminated (myopia, hyperopia,
astigmatism), which factors cannot be elimenated with specs? - correct answer.
Chromatic aberrations
high order aberations
Monochromatic aberrations is a result of light being more refracted in the periphery,
which types of monochromatic aberrations are there? - correct answer. - Defocus
- astigmatism
- spherical aberrations
- coma
- curvature in periphery
- distortion
Distortion occurs due to? - correct answer. Magnification differs in periphery
Chromatic aberrations occurs when?
What wave lengths gives most chromatic aberrations?
How does Abbe nr effect? - correct answer. high n
small wavelengths refract more
high abbe nr = less abberations
Aberrations mostly affect?
Scattering mostly affect? - correct answer. Young ppl when the pupil is large, ca 3 mm
is the best vision, fixed with specs.
old ppl, gets worse with age, glare and reduced contrast, fixed with cataract.
, Abbe number - correct answer. Measures possible chromatic aberration in a lens
material.
V nr decrease when N increace
Low V= alot of chromatic abbe
Plastic lens VS glass - correct answer. Plastic n=1.5 is better for semi/rimless frames,
Lighter,
Scratch resistance.
glass can have higher n.
Prismatic effercts - correct answer. Neg lens, kross moves up.
Pos lens kross moves down.
If we move the plus lens to the to the right:
Neg lens will move to the right
Pos lens will move opposite
If we put a lens of opposite sign with the same power, the prismatic effect dissapears.
Factors which effects lens thickness? - correct answer. Front surface power (base
curve)
refractive index
lens diameter (only pos lens)
Aspherical/spherical design
Curvature of lens influence - correct answer. Total thickness
abberations
magnification
Add number increaces with age - correct answer. Around 45 around 1 add
around 55 around 2 add
around 80 around 3 add
3 types of lenses to fix pressbyopia? - correct answer. reading
bifocal
progressive, no image jump
Bifocal segments for adults vs children? - correct answer. Adults right under eyelid
Children right under pupil
What lenses will be needed when pressbyopia? - correct answer. Emmetropes, will
need + lens for near distances
Myope, will need less neg at near distanses
hyperope will need + lens and sometimes also neg for far
Answers 100% Verified.
Lens factors which effects quality of vision - correct answer. Optical abberations
Reflectance (about 9% from both surfaces, no arc)
Light scattering
Lens factors such as low order abberations can be eliminated (myopia, hyperopia,
astigmatism), which factors cannot be elimenated with specs? - correct answer.
Chromatic aberrations
high order aberations
Monochromatic aberrations is a result of light being more refracted in the periphery,
which types of monochromatic aberrations are there? - correct answer. - Defocus
- astigmatism
- spherical aberrations
- coma
- curvature in periphery
- distortion
Distortion occurs due to? - correct answer. Magnification differs in periphery
Chromatic aberrations occurs when?
What wave lengths gives most chromatic aberrations?
How does Abbe nr effect? - correct answer. high n
small wavelengths refract more
high abbe nr = less abberations
Aberrations mostly affect?
Scattering mostly affect? - correct answer. Young ppl when the pupil is large, ca 3 mm
is the best vision, fixed with specs.
old ppl, gets worse with age, glare and reduced contrast, fixed with cataract.
, Abbe number - correct answer. Measures possible chromatic aberration in a lens
material.
V nr decrease when N increace
Low V= alot of chromatic abbe
Plastic lens VS glass - correct answer. Plastic n=1.5 is better for semi/rimless frames,
Lighter,
Scratch resistance.
glass can have higher n.
Prismatic effercts - correct answer. Neg lens, kross moves up.
Pos lens kross moves down.
If we move the plus lens to the to the right:
Neg lens will move to the right
Pos lens will move opposite
If we put a lens of opposite sign with the same power, the prismatic effect dissapears.
Factors which effects lens thickness? - correct answer. Front surface power (base
curve)
refractive index
lens diameter (only pos lens)
Aspherical/spherical design
Curvature of lens influence - correct answer. Total thickness
abberations
magnification
Add number increaces with age - correct answer. Around 45 around 1 add
around 55 around 2 add
around 80 around 3 add
3 types of lenses to fix pressbyopia? - correct answer. reading
bifocal
progressive, no image jump
Bifocal segments for adults vs children? - correct answer. Adults right under eyelid
Children right under pupil
What lenses will be needed when pressbyopia? - correct answer. Emmetropes, will
need + lens for near distances
Myope, will need less neg at near distanses
hyperope will need + lens and sometimes also neg for far
