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ABO Exam Latest 2024 – 2025 Complete
Answers 100% Correct
The extra-ocular muscles are inserted into the sclera and serve to rotate the eye in all
possible directions. There are _______of these muscles. - ANSWER >>Six
The fibrous tunic is comprised of the: - ANSWER>>Sclera and cornea
Fusion occurs: - ANSWER>>In the brain
The aqueous fluid is continually being manufactured by: - ANSWER>>The ciliary body
The ability of the eye to bring objects of varying distances to focus on the retina is
known as: - ANSWER>>Accommodation
When accommodation is at rest, rays of light from a distant source come to focus
behind the retina. This condition is known as: - ANSWER>>Hyperopia
Impulses are carried from the retina to the brain along the: - ANSWER>>Optic nerve
That area of the retina capable of perceiving the greatest amount of detail is: -
ANSWER>>Fovea centralis
The average cornea has a refractive power of approximately: - ANSWER>>43 diopters
The layer of the cornea which is highly regenerative is: - ANSWER >>The epithelium
Night vision is chiefly a function of the: - ANSWER>>Rods
A tendency of the visual axis to deviate inward while the eyes are in a position of rest is
known as: - ANSWER>>Esophoria
A "farsighted" eye is one that is: - ANSWER>>Hyperopic
The term used to indicate "double vision" is: - ANSWER>>Diplopia
The condition in which the ability to accommodate for near vision becomes inadequate
because of loss of elasticity of the crystalline lens is called: - ANSWER>>Presbyopia
When there is a loss of vision without any apparent disease of the eye it is known as: -
ANSWER>>Amblyopia
A refractive error in which the rays of light do not come to a single point of focus is
called: - ANSWER>>Astigmatism
The condition in which the crystalline lens of the eye gradually loses its transparency
with consequent loss of visual acuity is known as: - ANSWER>>Cataract
An ocular disease having as its primary characteristic a sustained increase in
intraocular pressure. - ANSWER>>Glaucoma
The space between the front of the iris and the innermost portion of the cornea (the
endothelium), this space is filled with aqueous. - ANSWER >>Anterior chamber
A tendency of one eye to deviate upward is: - ANSWER>>Hyperphoria
The layer of the cornea which comprises ninety percent of its thickness is: -
ANSWER>>The stroma
A condition in which the refractive error of one eye significantly differs from that of the
other and where both eyes have the same sign (i.e. both eyes are myopic or hyperopic)
is known as: - ANSWER>>Anisometropia
The refractive error which results in two points of focus falling behind the retina is: -
ANSWER>>Compound hyperopic astigmatism
The refractive condition caused by a damaged cornea so that rays of light come to
many focal points on the retina is known as: - ANSWER>>Irregular astigmatism
The index of refraction of the crystalline lens is: - ANSWER >>1.
The index of refraction of the cornea is: - ANSWER>>1.
Myopia means the eye
A. is nearsighted
B. has distance blur
C. requires a (-) minus lens
D. all of the above - ANSWER>>D. all of the above
The Retina contains
A. lab tools
B. lens information
D. none of the above - ANSWER>>D. none of the above
The following information is required on a written prescription:
A. doctor's name
B. doctor's signature
C. date
D. all of the above - ANSWER>>D. all of the above
The front surface of lenses can be measured using a ____________. -
ANSWER>>Lens clock (Geneva lens measurer).
High plus lenses will produce _________________ distortion while high minus lenses
will produce _____________ distortion. - ANSWER>>Pin cushion and barrel.
The unit of measurement for a wavelength of light is called _____________. -
ANSWER>>Nano-meters (nm)
The speed at which light travels is ______________, while _______________ refers to
the number of wave vibrations per second. - ANSWER>>Velocity, Frequency.
Give the wavelength range for UVA: __________ UVB: __________ UVC:
___________. - ANSWER>>UVA: 315-380 nm
UVB: 290-315 nm
UVC: 210-290 nm
Wavelengths in the ______________ colored part of the spectrum are thought to
provide the clearest vision. - ANSWER>>Green
The focal length of a .50 D lens is _________________. - ANSWER>>2 meters.
There are _________________ millimeters in one meter. - ANSWER >>One thousand
The color in the visible spectrum with the shortest wavelength is _________________. -
ANSWER>>Violet
Wavelengths that are "in phase" produce:
A. destructive interference
B. high frequencies
C. a big reflection
D. no reflection - ANSWER>>C. a big reflection
Anti-reflective coating causes an ______________ situation. - ANSWER>>out of phase
(destructive interference)
Minus lenses combine prisms:
A. base to base
B. apex to apex
C. apex to base
D. front to bakc - ANSWER>>B. apex to apex
Characteristics of a plus lens include:
A. "with motion"
B. real focal point
C. concave in shape
D. strengthens as vertex shortens - ANSWER>>B. real focal point
A prism re-directs light towards its ______________ while the object viewed will appear
to be displaced towards the ________________. - ANSWER >>Base; Apex.
In mixed astigmatism:
A. two focal lines form in front of the retina
B. one focal line forms on the retina and the other behind the retina
C. one focal line forms on the retina and the other in front of the retina
D. one focal line forms in front of the retina and the other forms behind the retina -
ANSWER>>D. one focal line forms in front of the retina and the other forms behind the
retina
In compound hyperopic astigmatism:
A. two focal lines form in front of the retina
B. two focal lines form behind of the retina
C. one focal line forms on the retina and the other in front of the retina
D. one focal line forms in front of the retina and the other forms behind the retina -
ANSWER>>B. two focal lines form behind of the retina
In simple hyperopic astigmatism:
A. two focal lines form in front of the retina
B. one focal line forms on the retina and the other behind the retina
C. one focal line forms on the retina and the other in front of the retina
D. one focal line forms in front of the retina and the other forms behind the retina -
ANSWER>>B. one focal line forms on the retina and the other behind the retina
- 1.50 - 0.75 X 90 is an example of :
A. mixed astigmatism
B. compound myopic astigmatism
C. simple myopic astigmatism
B. increases
C. remains the same
D. creates prism - ANSWER>>A. decreases
Astigmatism occurs because of:
A. an eye disease
B. needing correction sooner
C. an out-of-round cornea
D. a need for prism - ANSWER>>C. an out-of-round cornea
Prismatic situations that have no net prismatic imbalance are:
A. base in/base in
B. base out/base out
C. base in/base out
D. base up/base down - ANSWER>>C. base in/base out
A patient tells you that he has the sensation of walking uphill. What might you suspect?
A. base up prism
B. base down prism
C. base in prism
D. base out prism - ANSWER>>B. base down prism
A myopic patient has chosen a 54/16 frame. The patient's PD is OD 32. OS 33. How
much decentration would these lenses require and in what direction? If the lenses
weren't decentered, what would be the induced prismatic effect?
A. OD 2.5 mm in; OS 2.5 mm in; base out
B. OD 3 mm in; OS 2 mm in; base in
C. OD 2.5 cm out; OS 2.5 cm out; base up
D. OD 3 mm out; OS 2 mm out; base down - ANSWER>>B. OD 3 mm in; OS 2 mm in;
base in
Bicentric grinding (slab-off) is used when:
A. vertical imbalance exceeds 1.5 D of prism.
B. large difference in correction
C. base up prism is needed
D. any of the above - ANSWER >>D. any of the above
There is 5 D of prism created when a +4.00 lens is moved:
A. 12.5 mm
B. 1.25 mm
C. 12.5 cm
D. 5.00 mm - ANSWER>>A. 12.5 mm
A patient with a PD of 64 chooses a frame of 52/20. How much decentration will this
patient require and in what direction?
A. OD 3 mm in/OS 5 mm in
B. OD 4 mm in/OS 4 mm in
C. OD 3 cm out/OS 5 cm out
D. OD 4 mm out/OS 4 mm out - ANSWER>>B. OD 4 mm in/OS 4 mm in
The prism induced when a +4.00 D lens is moved 5 mm is:
A. 20 D of prism
B. .2 D of prism
C. 2 D of prism
D. .02 D of prism - ANSWER>>C. 2 D of prism
What is the amount and direction of the induced prism when a - 3.00 D lens is
decentered out 3 mm? A. 9 D of Base Out prism
B. 9 D of Base In prism
C. .9 D of Base Out prism
D. .9 D of Base In prism - ANSWER>>D. .9 D of Base In prism
Transpose the following prescriptions:
A. +1.75+0.75X
B. +1.25+1.00X
C. - 0.25+1.25X
D. - 1.00+1.50X
E. +0.25+2.25X
F. - 2.00+4.00X035 - ANSWER>>A. +2.50-0.75X
Convert the following prescriptions to reading only scripts.
A. OD: - 1.00-0.75x050 /+2.00 Add
OS: - 0.25-1.00x140/ +2.00 Add
B. OD: +1.25-1.25x068/ +1.75 Add
OS: +1.75-0.75x034/ +1.75 Add - ANSWER>>A. OD: +1.00-0.75x
OS: +1.75-1.00x
B. OD: +3.00-1.25x
OS: +3.50-0.75x
What is the term used to refer to a minus cylinder axis located near 90°?
A. "With Motion"
E. +2.50-2.25X
F. +2.00-4.00X
Focusing of the eye on a near object through relaxation of the ciliary muscle and
thickening of the lens. - ANSWER>>Accomodation
A refractive error in which the eye, when in a state of rest, does not focus the image of
an object upon the retina; includes hyperopia, myopia, and astigmatism. -
ANSWER>>Ametropia
A condition in which the ocular image of an object as seen by one eye differs so much
in size or shape from that seen by the other eye that images cannot be fused into a
single impression. - ANSWER>>Aniseikonia
A condition in which the refractive error of one eye significantly differs from that of the
other; each eye must have the same sign, i.e. both eyes are myopic or hyperopic. -
ANSWER>>Anisometropia
The refractive condition whereby the signs in each eye are opposite; one eye is
hyperopic while the other is myopic. - ANSWER>>Antimetropia
An absence of the crystalline lens of the eye. - ANSWER>>Aphakia
The clear watery fluid that fills the anterior and posterior chambers within the front part
of the eye. - ANSWER>>Aqueous humor
A refractive error that prevents the light rays from coming to a single focus on the retina
because of different degrees of refraction in the various meridians of the eye. -
ANSWER>>Astigmatism
A condition in which the crystalline lens of the eye, or its capsule, or both, become
opaque, with consequent loss of visual acuity. - ANSWER >>Cataract
That portion of the vascular coat between the iris and the choroid. It consists of ciliary
processes and the ciliary muscle. - ANSWER>>Ciliary body
The refractive error which results in two points of focus falling behind the retina. -
ANSWER>>Compound hyperopic astigmatism
The vascular intermediate coat that furnishes nourishment to other parts of the eyeball.
ANSWER
Choroid
The refractive error which results in two points of focus falling in front of the retina. -
ANSWER>>Compound myopic astigmatism
The clear transparent portion of the outer coat of the eyeball forming the covering of the
aqueous chamber. - ANSWER>>Cornea
A transparent colorless body suspended in the front part of the eyeball, between the
aqueous and the vitreous, the function of which is to bring the rays of light to a focus on
the retina. - ANSWER>>Crystalline lens
The seeing of one object as two (Double vision). - ANSWER >>Diplopia
The refractive condition of the normal eye. When the eye is at rest, the image of distant
objects is brought to focus on the retina. - ANSWER>>Emmetropia
A small depression in the retina at the back of the eye; the part of the macula adapted
for most acute vision. - ANSWER>>Fovea
The power of coordination by which the images received by the two eyes becomes a
single image. - ANSWER>>Fusion
An ocular disease having as its primary characteristic a sustained increase in intraocular
pressure that the eye cannot withstand without damage to its structure or impairment of
its function. - ANSWER>>Glaucoma
A refractive error in which, because the eyeball is short of the refractive power of the
lens is weak, the point of focus for rays of light from distant objects falls behind the
retina; accommodation to increase the refractive power of the lens is necessary for
distance vision as well as near vision. - ANSWER>>Hyperopia
The colored circular membrane suspended behind the cornea and immediately in front
of the lens. The _____ regulates the amount of light entering the eye by changing the
size of the pupil. - ANSWER>>Iris
A refractive condition caused by a cornea which is damaged and irregular so that rays
of light come to many focal points on the retina; is not correctable by cylinders. -
ANSWER>>Irregular astigmatism
Spectacle lenses specially designed to manipulate image size when dissimilar sizes
makes it difficult or impossible for fusion to occur (aniseikonia). - ANSWER>>Iseikonic
How many cones are there and what visual purpose do they serve? - ANSWER>>• 6
Million
- Day vision
- Shows detail
- Color
The white part of the eye; a tough covering which, with the cornea, forms the external
protective coat of the eye. - ANSWER>>Sclera
A blind area of reduced vision in the visual field. - ANSWER>>Scotoma
The refractive condition where one point of focus falls on the retina and the other point
of focus falls behind the retina. - ANSWER>>Simple hyperopic astigmatism
The refractive condition where one point of focus falls on the retina and the other point
of focus falls in front of the retina. - ANSWER>>Single myopic astigmatism
Failure of two eyes to simultaneously direct their gaze at the same object because of
muscle imbalance. Also known as a squint. - ANSWER>>Strabismus
Numerous fine tissue strands that stretch from the ciliary processes to the lens equator
and support the lens in place. - ANSWER>>Suspensory ligaments
A root word denoting an obvious deviation from normal of the axis of the eyes; used
with a prefix to denote the type of strabismus. - ANSWER >>Tropia
The Index of refraction of the Aqueous and vitreous humor is: - ANSWER>>1.
These layers are in:
- Epithelium
- Bowman's membrane
- Stroma
- Desemet's membrane
- Endothelium - ANSWER>>Cornea
What are the layers of the cornea? - ANSWER>>• Epithelium
How many rods are there and what visual purpose do they serve? - ANSWER
• 120
million
- Night vision
- Peripheral
- Black and white
- Bowman's membrane
- Stroma
- Desemet's membrane
- Endothelium
Total thickness of the cornea. - ANSWER>>0.50mm
Thickest part of cornea (makes up 90%). - ANSWER>>Stroma
When a high powered minus lens is moved closer to the eye, the compensated power
must: - ANSWER>>Be decreased.
When a plus lens is moved closer to the eye, it's effective power: -
ANSWER>>Decreases
Fused bifocals are available in: - ANSWER >>Flat top and Round
In a round bifocal segment you find the optical center located: - ANSWER>>In the
geometric center.
The intermediate power most common in tri-focal lenses is: - ANSWER>>50% of the
add power
Which bifocal segment contains the least amount of image jump? - ANSWER>>Flat top
What is the Index of refraction for Polycarbonate? - ANSWER>>1.
What is the index of refraction for Air: - ANSWER>>1.
What is the index of refraction for Crown Glass? - ANSWER >>1.
What is the index of refraction for CR-39? - ANSWER>>1.
What is the index of refraction for Hi-index? - ANSWER>>1.
It is important to consider vertex distance in spectacle lenses when the power exceeds:
ANSWER
>>± 7.00 D
Progressive power lenses require the following measurements in order to be accurately
fit: - ANSWER>>Monocular PD and monocular seg height.
When the bottom of the eye-wire is inclined outward, further away from the face than
the top, it is called: - ANSWER>>Retroscopic tilt.
Common plastic frame material used for eyeglass frames. - ANSWER>>Zylonite, also
known as Cellulose Acetate.
A durable material that is injection molded, rather than cut from a flat sheet. Ideal for
wrap frames. Requires less heat for adjustments and lens insertion. -
ANSWER>>Cellulose Proprionate.
Epoxy material that is lightweight. Cannot be overheated or burned, also it will not
shrink. "Memory". - ANSWER>>Optyl
Synthetic material from coal, water, and air. Light weight and very strong, often used in
children's frames and industrial safety eye-wear. Requires significant heat for lens
insertion. - ANSWER>>Nylon
Strong, light weight, shape retention unaffected by heat. Resistant to scratching and
made nearly as thin as metal: - ANSWER>>Carbon fiber.
Highly impact resistant frame, used for safety and sports: - ANSWER >>Polycarbonate
frame
Durable, light weight and flexible. Injection molded and holds colors very well. Material
will shrink when heated. Lenses must be cut to exact size. -
ANSWER>>Polymide/copolyamide
Also used in bullet-proof vests and sports equipment because of its high tensile
strength. Injection molded and very strong. - ANSWER>>Kevlar
Made of special titanium and nickel alloy. Frames have memory. - ANSWER>>Memory
metal
Holds shape the best of any metal combination. Not as malleable as some other
materials, often used for standard navigator and pilot shapes. The most popular metal
for frames because it accepts plating well and can be plated in many colors. -
ANSWER>>Nickel silver
One of the most used metals for frames. Corrosion-resistant, it works well with all
colors. Difficult to shape for lenses so material is mostly used for temples, bridges, and
fronts, not eye-wires. Strong solder joints and finish does not wear off. -
ANSWER>>Monel
Always used in combination with other materials like nickel, copper, beryllium and
chrome. - ANSWER>>Gold
This is not used because of its softness. Instead white gold is used instead: -
ANSWER>>Silver
Relatively new material. Very light weight, durable, and available in many colors and
styles. - ANSWER>>Titanium
Metal that is light weight, long lasting, may be anodized which allows for many colors: -
ANSWER>>Aluminum
Noncorrosive, strong, and light in weight. - ANSWER>>Stainless steel
When helping a customer with high minus lenses, what should be recommended? -
ANSWER>>• Small eyesize
- Thicker frame construction
- Rounder shapes
- Lightweight lenses
- High-index (thinner) lenses
- Anti-reflective coating
- Edge coating
When helping a customer with high plus lenses, what should be recommended? -
ANSWER>>• Small eyesize
- Sturdy frame
- Round shape
- Adjustable nosepads
- Light weight Hi-index lenses
An instrument used for measuring vertex distance: - ANSWER>>Distometer
A laboratory instrument for measuring internal lens stress: - ANSWER>>Polariscope
Glass lenses in which the power exceeds ± 7.00 D should be: - ANSWER>>Chemically
treated only.
Highest index of refraction in the eye is 1.42 and is associated with: -
ANSWER>>Crystalline lens
"Conventional" slab-off is ground with base up prism in the reading portion only on the
lens with the ___________ in the vertical meridian. - ANSWER>>Most minus power.
Reverse slab-off is ground with base down prism in the reading portion only on the lens
with the ___________ in the vertical meridian. - ANSWER >>Most plus power.
According to ANSI Standards, the tolerance for base curves is: - ANSWER>>+/- 0.75d
The ______ is an agency of the U.S. Government which enforces Federal laws against
unfair trade practices: - ANSWER>>Federal Trade Commission
What is the wavelength of ultra violet radiation?
A. Shorter than visible blue waves
B. Longer than visible red waves
C. 580 nanometers
D. Between 380 and 720 nanometers - ANSWER>>A. Shorter than visible blue waves
A lens that has two curves on the front surface is a:
A. Myopic lens
B. Toric lens
C. Spherical lens
D. Plus cylinder lens - ANSWER>>D. Plus cylinder lens
A lens reads +2.25 in the vertometer. If the ocular curve is - 6.00, what is the anterior
curve? A. +2.
B. +6.
C. +8.
D. +10.25 - ANSWER>>C. +8.
The patient's interpupillary distance is 68 and the frame PD is 76. What is the required
decentration for each eye?
A. 8
B. 6
C. 4
D. 2 - ANSWER>>C. 4
A prescription +1.00 - 2.25 x 090, would indicate which of the following conditions?
A. Compound hyperopic astigmatism
B. Simple myopic astigmatism
C. Compound myopic astigmatism
D. Mixed astigmatism - ANSWER>>D. Mixed astigmatism
Hyperopic corrective lenses for presbyopic patients will produce what prismatic effect in
the reading area?
A. Base up
B. Base out
C. Base down
D. Base in - ANSWER>>A. Base up
Keratitis is an inflammation of what?
A. Conjunctiva
B. Cornea
C. Sclera
D. Retina - ANSWER>>B. Cornea
The reading only prescription for a - 4.25-1.25x090, add +2.00 is:
A. - 2.25 - 1.25x
B. - 6.25 - 1.25x
C. - 2.25 sph
D. +2.00 sph - ANSWER>>A. - 2.25 - 1.25x
A plastic photochromic lens is helpful in what two areas due to uniform tint?
A. Bifocals and high plus lenses
B. Plano and low plus lenses
C. Fused bifocals and low plus lenses
D. Fused trifocals and low plus lenses - ANSWER>>A. Bifocals and high plus lenses
Which of the following UV areas is completely absorbed by the atmosphere?
A. UVA
B. UVB
C. UVC
D. UVD - ANSWER>>C. UVC
The MRP is located at the lens-optical center:
A. At all times
B. When base out prism is prescribed
C. When single vision lenses are prescribed
D. When no prism is prescribed - ANSWER>>D. When no prism is prescribed
