ABO Practice Test(Questions and Answers 100% correct)
When discussing thick lenses, the factors which are considered in computing the lens power are:
a. front curve, thickness and index
b. back curve, thickness and index
c. front curve, back curve and thickness
d. front curve, back curve, thickness and index - (Answer)d. front curve, back curve, thickness and
index
Toric transposition shows:
a. lens thickness
b. power in principal meridians
c. the power of the ADD
d. the lens diameter - (Answer)b. power in principal meridians
Increasing the diameter of a minus power lens always increases its:
a. vertex power
b. center thickness
c. weight
d. refractive index - (Answer)c. weight
The optical center of a round segment is located:
a. at the very top of the segment
b. in the geometric center of the segment
,ABO Practice Test(Questions and Answers 100% correct)
c. 5 mm from the top of the segment
d. at the very bottom of the segment - (Answer)b. in the geometric center of the segment
The base curve of any multifocal lens is found on the surface containing the:
a. cross curve
b. cylinder surface
c. segment
d. ocular curve - (Answer)c. segment
Normal slab-off (bicentric grind) is ground on the lens whose vertical meridian has the:
a. strongest curves
b. most plus power
c. least plus power
d. least minus power - (Answer)c. least plus power
The refractive error indicated by the Rx +1.75 -2.75 x 090 is:
a. compound hyperopic astigmatism
b. compound myopic astigmatism
c. simple myopic astigmatism
d. mixed astigmatism - (Answer)d. mixed astigmatism
Tempering a lens by heat treating results in a lens being:
,ABO Practice Test(Questions and Answers 100% correct)
a. less resistant to impact
b. more resistant to impact
c. more resistant to surface scratching
d. impossible to break - (Answer)b. more resistant to impact
A slab-off lens is for the correction of:
a. astigmatic errors
b. excessive weight of lens
c. excessive prism imbalance at the reading level
d. exotropia - (Answer)c. excessive prism imbalance at the reading level
Chem-tempering makes a glass lens more impact resistant by placing the lens in a potassium nitrate
bath. The lens undergoes a process known as:
a. ion exchange
b. iron oxide activation
c. silver halide transfer
d. thermal bleaching - (Answer)a. ion exchange
Which wavelengths of light have been indicated as possible contributors to the onset of cataracts?
a. 400-520 nm
b. 520-635 nm
c. 350-400 nm
, ABO Practice Test(Questions and Answers 100% correct)
d. 635-750 nm - (Answer)c. 350-400 nm
When the lenses are laid out and marked for cutting and edging, the lenses are usually decentered so
as to correspond to the patient's pupillary distance after lenses are inserted. This is done for the
following reason:
a. to avoid unwanted prism
b. for cosmetic effect
c. to use off-center lenses
d. to avoid thick edges on the nasal side - (Answer)a. to avoid unwanted prism
Light falling on the front surface of a spectacle lens is:
a. partially reflected, partially absorbed and the remainder refracted
b. partially reflected and the remainder refracted
c. partially absorbed and the remainder refracted
d. totally refracted - (Answer)a. partially reflected, partially absorbed and the remainder refracted
A concave mirror:
a. can focus parallel incident rays to form a real image
b. can focus parallel incident rays to form a virtual image
c. always produces inverted images of real objects
d. produces virtual images smaller than the real object - (Answer)a. can focus parallel incident rays to
form a real image
When discussing thick lenses, the factors which are considered in computing the lens power are:
a. front curve, thickness and index
b. back curve, thickness and index
c. front curve, back curve and thickness
d. front curve, back curve, thickness and index - (Answer)d. front curve, back curve, thickness and
index
Toric transposition shows:
a. lens thickness
b. power in principal meridians
c. the power of the ADD
d. the lens diameter - (Answer)b. power in principal meridians
Increasing the diameter of a minus power lens always increases its:
a. vertex power
b. center thickness
c. weight
d. refractive index - (Answer)c. weight
The optical center of a round segment is located:
a. at the very top of the segment
b. in the geometric center of the segment
,ABO Practice Test(Questions and Answers 100% correct)
c. 5 mm from the top of the segment
d. at the very bottom of the segment - (Answer)b. in the geometric center of the segment
The base curve of any multifocal lens is found on the surface containing the:
a. cross curve
b. cylinder surface
c. segment
d. ocular curve - (Answer)c. segment
Normal slab-off (bicentric grind) is ground on the lens whose vertical meridian has the:
a. strongest curves
b. most plus power
c. least plus power
d. least minus power - (Answer)c. least plus power
The refractive error indicated by the Rx +1.75 -2.75 x 090 is:
a. compound hyperopic astigmatism
b. compound myopic astigmatism
c. simple myopic astigmatism
d. mixed astigmatism - (Answer)d. mixed astigmatism
Tempering a lens by heat treating results in a lens being:
,ABO Practice Test(Questions and Answers 100% correct)
a. less resistant to impact
b. more resistant to impact
c. more resistant to surface scratching
d. impossible to break - (Answer)b. more resistant to impact
A slab-off lens is for the correction of:
a. astigmatic errors
b. excessive weight of lens
c. excessive prism imbalance at the reading level
d. exotropia - (Answer)c. excessive prism imbalance at the reading level
Chem-tempering makes a glass lens more impact resistant by placing the lens in a potassium nitrate
bath. The lens undergoes a process known as:
a. ion exchange
b. iron oxide activation
c. silver halide transfer
d. thermal bleaching - (Answer)a. ion exchange
Which wavelengths of light have been indicated as possible contributors to the onset of cataracts?
a. 400-520 nm
b. 520-635 nm
c. 350-400 nm
, ABO Practice Test(Questions and Answers 100% correct)
d. 635-750 nm - (Answer)c. 350-400 nm
When the lenses are laid out and marked for cutting and edging, the lenses are usually decentered so
as to correspond to the patient's pupillary distance after lenses are inserted. This is done for the
following reason:
a. to avoid unwanted prism
b. for cosmetic effect
c. to use off-center lenses
d. to avoid thick edges on the nasal side - (Answer)a. to avoid unwanted prism
Light falling on the front surface of a spectacle lens is:
a. partially reflected, partially absorbed and the remainder refracted
b. partially reflected and the remainder refracted
c. partially absorbed and the remainder refracted
d. totally refracted - (Answer)a. partially reflected, partially absorbed and the remainder refracted
A concave mirror:
a. can focus parallel incident rays to form a real image
b. can focus parallel incident rays to form a virtual image
c. always produces inverted images of real objects
d. produces virtual images smaller than the real object - (Answer)a. can focus parallel incident rays to
form a real image
