CH 4 Ophthalmic Optics and Dispensing

• __________ lenses are also called convex lenses. They are

  thick in the center and thin on the edges. Light rays passing

  through these lenses will be converged.

  
  

  a) Plus

  
  

  b) Minus

  
  

  c) Cylinder

  
  

  d) None of the above


  a) Plus
• __________ lenses are thin in the center and thick on the

  edges. Objects viewed through these lenses will appear smaller

  or minified. Light rays passing through these lenses will be

  diverged.

  
  

  a) Cylinder

  
  

  b) Plus

  
  

  c) Minus

  
  

  d) Convex

  c) Minus
• What instrument is used to verify the spectacle prescription?

  
  

  a) Tonometer

  
  

  b) Auto Refractor

  
  

  c) Keratometer

  
  

  d) Lensometer

  d) Lensometer
• When viewing a lens through the instrument above, you take

  the following measurements: sphere +2.50, cylinder -1.75, axis

  172. How would the prescription for this lens be written?

  
  

  a) +2.50 -1.75 x 172

  
  

  b) -1.75 + 2.50 x 172

  
  

  c) +2.50 sphere

  
  

  d) +1.75 -2.50 x 172


  a) +2.50 -1.75 x 172
• All the following statements concerning prism are true

  except:

  a) A prism’s shape is similar to a pyramid

  b) Light moving through a prism is bent toward the apex

  c) One prism diopter will bend a ray of light 1 centimeter forevery 1 meter of distance

  d) A prism can be oriented in any direction in order to meet apatient’s needsb) Light moving through a prism is bent toward the apex
• Which of the following terms is used to designate a

  lens without power?

  
  

  a) Plano

  
  

  b) Minus

  
  

  c) Convex

  
  

  d) Avascular

  a) Plano
• Which of the following lenses has the same power in

  all areas of the lens and is used to treat myopia or

  hyperopia?

  
  

  a) Spherical

  
  

  b) Cylindrical

  
  

  c) Planocylindrical

  
  

  d) Spherocylindrical

  a) Spherical
• Which of the following lens materials has the hardest

  surface and is also the heaviest?

  
  

  a) CR-39

  
  

  b) High-Index

  
  

  c) Polycarbonate

  
  

  d) Glass

  d) Glass
• Which of the following lens materials is the most

  shatter-resistant?

  
  

  a) Glass

  
  

  b) Polycarbonate

  
  

  c) High-Index

  
  

  d) CR-39

  d) CR-39
• Which type of lens corrects vision at three

  distances?

  
  

  a) Bifocal

  
  

  b) Round 22

  
  

  c) Trifocal

  
  

  d) Progressive Addition Lenses

  c) Trifocal
• The part of the frame that surrounds each lens, holding the lens

  in place within the frame, is the:

  
  

  a) Temple

  
  

  b) Hinge

  
  

  c) Bridge

  
  

  d) Eyewire

  d) Eyewire
• The part of the frame that extends from the frame front, back

  alongside the head, and over the ear of the wearer is the:

  
  

  a) Hinge

  
  

  b) Temple

  
  

  c) Bridge

  
  

  d) Eyewire

  b) Temple
• The widest horizontal dimension of the lens opening of a frame

  is the:

  
  

  a) ED

  
  

  b) DBL

  
  

  c) A Dimension

  
  

  d) B Dimension

  c) A Dimension
• A picture representation of the pressure points between the

  eyeglasses frame and the patient's head is the:

  
  

  a) Fitting Triangle

  
  

  b) Face Form

  
  

  c) Pantoscopic Angle

  
  

  d) Vertex Distance

  a) Fitting Triangle
• Which of the following tilts results when a pair of spectacles is

  tilted so that the bottom of the lenses is closer to the face

  than the top?

  
  

  a) Pantoscopic

  
  

  b) Retroscopic

  
  

  c) Orthoscopic

  
  

  d) Face form

  a) Pantoscopic
• The largest diameter through the lens is called the:

  
  

  a) Effective diameter

  
  

  b) Distance between the lenses

  
  

  c) C Dimension

  
  

  d) High Index

  a) Effective diameter
• A lens that converges parallel light is called __________________.

  Convex (+)
• The unit of measurement for ophthalmic lenses is __________________.

  Diopter
• A lens that displaces light rather than

  focuses light is called ________________.

  Prism
• A _____________ lens diverges parallel

  light.

  Concave (-)
• A lens that has one curve is called a

  _____________________.

  Spherical
• The point of a prism is called the ______________________.

  Apex
• A lens where one part has no power and 90 degrees away there is power is called a ______________________.

  Pl-Cylinder
• A lens used to treat myopia/hyperopia and astigmatism is called a _______________.

  Sph/Cylindrical
• The middle value of a lens prescription is called the ______________________.

  Cylindrical
• The position of the cylinder in the lens is called the ______________________.

  Axis
• A light ray striking a surface at 90 degrees will:

  
  

  a) Move from left to right

  
  

  b) Bend

  
  

  c) Slow down

  
  

  d) Both B & C

  c) Slow down
• One meter is equal to ________ centimeters and ________ millimeters.

  100; 1,000
• A 1.00 D lens will refract light rays to a focus of ___________ from the lens.

  1 meter
• Which of the following lens powers has the shortest focal length?

  
  

  a) 2.00 D

  
  

  b) 3.00 D

  
  

  c) 1.50 D

  
  

  d) 1.00 D


  b) 3.00 D
• The pointed tip of a prism is know as the:

  
  

  a) Apex

  
  

  b) Base


  a) Apex
• Light rays passing through a prism will be bent toward the"

  
  

  a) Apex

  
  

  b) Base


  b) Base
• Prism power is measured in units of _________________________.

  Prism diopters
• A 1Δ prism will displace an image _______ cm for every ______ m of distance.

  1; 1