COT Exam Review Manual Flashcards
The range of range of wavelength in the visible spectrum is:
a. 100 to 400 nanometers
b. 400 to 800 nanometers
c. 450 to 650 nanometers
d. 400 to 800 meters (m)
b. 400 to 800 nanometers
Make sure to pay attention to the units of measurement used as this can trip you up.. option D has m not nm.
Immediately on either side of the visible spectrum are the invisible light segments of:
a. infrared and ultraviolet
b. X-rays and radio waves
c. gamma rays and lasers
d. microwaves and radar
a. infrared and ultraviolet
Infrared light borders the visible color red and ultraviolet light borders the visible color violet. All of the other answers are invisible components of the electromagnetic spectrum, but do not abut red or violet.
Which color has the longest wavelength?
a. red
b. yellow
c. green
d. blue
a. red
Red’s wavelength is 650 nanometers
Geometric optics includes:
a. the origin of light waves and particles
b. the effects of media on the path of light
c. how light travels through the eye
d. physics of the visible light spectrum
b. the effects of media on the path of light
Geometric optics involves the reaction of light as it passes through media (any transparent object) or strikes a surface. Answers a & d refer to physical optics. Physiologic optics defines answer c.
When light bounces back from an object, this is known as:
a. reflection
b. refraction
c. transmission
d. index of refraction
a. reflection
In reflection, the light rays that hit the object or interface between media with different indices of refraction are called:
a. incident rays
b. reflected rays
c. refracted rays
d. transmitted rays
a. incident rays
The light that hits the object or interface is termed incident, those rays that bounce back from the object or interface are called reflected.
In optics, a medium (or media, plural) is:
a. an object that refracts light
b. an object that emits light
c. an object that reflects light
d. an object through which light passes
d. an object through which light passes through
A medium is a transparent object through which light can pass. It is not a light source (ie, does not emit light) it does not necessarily refract light, either.
When light passes through a transparent medium, it may travel straight through (transmission) or its path may be altered. This altering or bending property of a medium is known as:
a. reflection
b. refraction
c. absorption
d. tropism
b. refraction
The quality of a medium to bend light is called refraction. In reflection, the rays are bounced off of the surface. Absorbed light does not pass through a medium. Tropism actually refers to the phenomenon of plants bending toward a light source.
The ray of light that enters a transparent medium is termed:
a. incident ray
b. divergent ray
c. emergent ray
d. parallel ray
a. incident ray
The incident ray is the ray that first strikes and enters a medium. A divergent ray has been refracted outward. The emergent ray is the ray as it exits the medium. A parallel ray is straight.
If light passes through a lens and the rays are spread apart on exiting, this is known as:
a. index of refraction (IR)
b. convergence
c. zero vergence
d. divergence
d. divergence
If light passes through a lens and the rays are bent toward each other on existing, this is known as:
a. IR (Index of refraction)
b. convergence
c. zero convergence
d. divergence
b. convergence
A comparison of the speed of light in air to the speed of light through a substance is:
a. IR (snell’s law)
b. angle of refraction
c. internal reflection
d. optical interference
a. IR (snell’s law)
The IR of a substance is found by dividing the speed of light in the air by the speed of light through the substance. This is also known as Snell’s Law.
The denser the substance, the more slowly light passes through it, and:
a. the lower the IR
b. the higher the IR
c. the more transparent it is
d. the more suitable it is for use as an ophthalmic lens
b. the higher the IR
The IR of crown glass is:
a. 0
b. 1.00
c. 1.33
d. 1.50
d. 1.50
Light traveling through a vacuum is zero, through air is 1.0 and through water is 1.33
Light traveling through a prism will be bent toward the prism’s:
a. apex
b. base
c. center
d. smallest angle
b. base
The image of an object viewed through a prism:
a. is real and shifted toward the base
b. is virtual and shifted toward the base
c. is real and shifted toward the apex
d. is virtual and shifted toward the apex
d. is virtual and shifted toward the apex
A 1.00 diopter prism bends light:
a. 1 centimeter (cm) at a distance of 1 cm from the prism
b. 1 m at a distance of 1 cm from the prism
c. 1 cm at a distance of 1 m from the prism
d. 1 m at a distance of 1 m from the prism
c. 1 cm at a distance of 1 m from the prism
A 2.oo diopter prism displaces an object 1 cm at a distance of:
A. 0.2 m
B. 0.5 m
C. 1.5 m
D. 5.0 cm
B. 0.5 m
The displacement of an object 5 cm at a distance of 1 m would require prism of:
A. 0.5 diopters
B. 1.0 diopters
C. 2.0 diopters
D. 5.0 diopters
D. 5.0 diopters
At a distance of 2 m, a 12 diopter prism would displace an object:
A. 6 cm
B. 2.4 m
C. 24 cm
D. 6 m
C. 24 cm
A spherical lens refracts light:
A. Not at all
B. In one direction only
C. Equally in every direction
D. At 90 degrees from its axis
C. Equally in every direction
A 1.00 diopter spherical lens focuses light at:
A. 1/2 m
B. 1 m
C. 1 cm
D. 1 yard (yd)
B. 1 m
The point at which a lens forms an image (whether real or virtual) is the:
A. Nodal point
B. Conoid of Sturm
C. Focal Length
D. Focal Point
D. Focal Point
All of the following regarding the optical center of a lens is true except:
A. It always coincides with the geometric center of the lens
B. Light rays passing through it are not refracted
C. It also is known as the nodal point
D. It should be centered in line with the patient’s visual axis
A. It always coincides with the geometric center of the lens
The focal length of a lens:
A. Is the distance between the lens and the focal point
B. Is the dioptric power of the lens
C. Is the point where light is focused
D. Is related to the axis of the cylinder
A. Is the distance between the lens and the focal point
Because the focal point of a minus lens is virtual, the focal length of a minus lens:
A. Cannot be calculated
B. Is likewise virtual
C. By contrast, is real
D. Is insignificant
B. Is likewise virtual
Which of the following is the formula for finding focal length?
A. IR = speed of light in air/speed of light in substance
B. P = C/D
C. P = I/F
D. U + P = V
C. P = I/F
What is the focal length of a 5 diopter lens?
A. 5 m
B. 0.5 m
C. 2 m
D. 0.2 m
D. 0.2 m
A lens has a focal length of 33 cm. What is its dioptric power?
A. 0.03 diopters
B. 0.3 diopters
C. 3 diopters
D. 30 diopters
C. 3 diopters
Lens Characteristics of Plus Spherical Lenses
- Converges Light
- Used to correct presbyopia in the emmetrope
- Thicker in the middle
- Used to correct aphasia
- Magnifies
- Two prisms placed based to base
- Pincushion distortion
- Used to correct hyperopia
- Convex
- Real image
Lens Characteristics of Minus Spherical Lenses
- Virtual image
- Minifies
- Barrel distortion
- Concave
- Used to correct myopia
- Diverges light
- Two prisms placed apex to apex
- Thinner in the middle
All of the following regarding cylindrical lenses are true except:
A. They are used to correct astigmatism
B. They have power in one axis, but no power in the axis 90 degrees away
C. They focus light in a line
D. They are plus power lenses
D. They are plus power lenses
The direction of the line of light as focused by a plus cylindrical lens:
A. Is virtual and cannot be placed
B. Is 90 degrees from the axis
C. Is aligned with the axis
D. Is 45 degrees from the axis
C. Is aligned with the axis
Light passing through a cylindrical lens is focused in two lines perpendicular to each other and separated by an area known as:
A. Induced interval
B. Sturm’s interval
C. Anterior focal interval
D. Posterior focal interval
B. Sturm’s interval
The light rays in the above-mentioned interval are projected in the shape of a:
A. Circle
B. Prism
C. Curve
D. Cone
D. Cone
Within the Conoid of Sturm, the area where the image would be most clearly focused is:
A. The circle of least confusion
B. The cone of least confusion
C. The focus of least confusion
D. The secondary focal point
A. The circle of least confusion
An optical cross is a means of:
A. Marking the optical center of lens
B. Calculating the amount of induced prism
C. Determining whether or not a lens is polarized
D. Indicating the dioptric power of a lens
D. Indicating the dioptric power of a lens
The ocular media consists of:
A. They lens of correction for ametropia
B. Contact lenses and intraocular lenses
C. The eyelid, sclera, urea, and optic nerve
D. The tear film, cornea, humors, and lens
D. The tear film, cornea, humors, and lens
All of the following are true regarding the accommodative reflex except:
A. It is stimulated by a blurred image
B. It is not a true reflex
C. It is required for viewing distance objects
D. It includes convergence, mitosis, and focusing
C. It is required for viewing distance objects
When the ciliary muscle relaxes:
A. Close objects become clear
B. There is more focusing power
C. The lens is pulled thinner
D. The zonules go limp
C. The lens is pulled thinner
The main reason one’s accommodative ability decreases with age is due to:
A. One’s arms becoming shorter
B. Laxity in the ciliary muscle
C. Laxity of the zonules
D. Hardening of the crystalline lens
D. Hardening of the crystalline lens
With accommodation fully relaxed, what is the patient’s point of clearest vision?
A. The far point
B. The near point
C. Accommodative amplitude
D. Range of accommodation
A. The far point
The “power” of a myopic eye itself is:
A. Minus
B. Plus
C. Neutral
D. Irrelevant
B. Plus
The retinoscope provides information on the patient’s refractive status by:
A. Reflecting light off the patient’s cornea
B. Reflecting light off the patient’s retina
C. Reflecting light off the patient’s lens
D. Projecting light from the examiner’s retina
B. Reflecting light off the patient’s retina
The streak retinoscope permits:
A. No comparison of principal meridians
B. Neutralization of individual ocular meridians
C. Subjective measurement of nonverbal patients
D. Correction of plus cylinder only
B.Neutralization of individual ocular meridians
All of the following are components of the streak retinoscope except:
A. Light and power source
B. Condensing lens and mirror
C. Rotating lens system
D. Focusing sleeve
C. Rotating lens system
Raising or lowering the focusing sleeve of a streak retinoscope:
A. Rotates the streak to evaluate all meridians
B. Change the vergence of the light leaving the instrument
C. Permits measuring of hyperopia or myopia
D. Adjusts for the examiner’s own refractive error
B. Changes the vergence of the light leaving the instrument
The plane mirror effect is used in streak retinoscope because:
A. It is easier to use the instrument with the sleeve up
B. It is easier to use the instrument with the sleeve down
C. This projects parallel light rays into the eye
D. This projects converging light rays into the eye
C. This projects parallel light rays into the eye
If a streak retinoscope is habitually placed flat on the table:
A. This is an acceptable practice
B. The lenses may get scratched, causing a distorted reflex
C. The mirror will be jarred out of alignment
D. The filament may bend, causing a distorted streak
D. The filament may bend, causing a distorted streak
A working lens is required in retinoscope in order to:
A. Simulate working at infinity
B. Simulate working at 10 m
C. Simulate working at 66 cm
D. Simulate working at 14 inches (in)
A. Simulate working at infinity
Standard retinoscope working distance is:
A. 50 cm
B. 66 cm
C. 75 cm
D. 88 cm
B. 66 cm
If you use a retinoscopy working distance that is closer than the standard, your working lens will need to be:
A. The same at any working distance
B. More plus power than standard
C. More minus power than standard
D. One should work at the standard distance only
B. More plus power than standard
Which of the following can be determined with the most accuracy using a streak retinoscope?
A. Sphere power
B. Sphere axis
C. Cylinder power
D. Cylinder axis
D. Cylinder axis
The magnitude of a refractive error can often be evaluated by noting all of these streak qualities except:
A. Brightness
B. Width
C. Speed
D. Height
D. Height
In streak retinoscopy, the intercept is:
A. That part of the streak that is reflected from the pupil
B. When the streak is swept at 90 degrees
C. When the streak is swept at 180 degrees
D. The part of the streak that falls on the patient’s iris
D. The part of the streak that falls on the patient’s iris
If you sweep the retinoscope streak across the patient’s pupil and the reflex travels in the same direction as the intercept, this is known as:
A. Neutrality
B. “With” motion
C. “Against” motion
D. Luminosity
B. “With” motion
Most retinoscopists prefer to neutralize “with” motion because”
A. They work in plus sphere
B. They work in minus sphere
C. “Against” motion can be difficult to evaluate
D. “With” motion can be difficult to evaluate
C. “Against” motion can be difficult to evaluate
One can convert any situation to “with” motion by adding:
A. Plus cylinder
B. Minus cylinder
C. Enough plus sphere
D. Enough minus sphere
D. Enough minus sphere
One matches the retinoscope streak to the axis of the refractive error by:
A. Rotating the sleeve until there is an unbroken line
B. Raising the sleeve until there is an unbroken line
C. Lowering the sleeve until there is an unbroken line
D. Turning the instrument until there is an unbroken line
A. Rotating the sleeve until there is an unbroken line
As the measurement approaches neutrality, the reflex will become:
A. Dimmer, slower, and longer
B. Brighter, wider, and faster
C. Brighter, narrower, and faster
D. Brighter, wider, and slower
B. Brighter, wider, and faster
At the point of neutrality, the reflex will:
A. Be clearer to the patient
B. Appear as a fine line
C. Seem to blink on and off
D. Disappear entirely
C. Seem to blink on and off
All of the following regarding use of the streak retinoscope are true except:
A. Keep the room lights low
B. Keep both of your eyes open
C. Measure the patient’s right eye with your right eye
D. When using your right eye, hold the retinoscope in your left hand
D. When using your right eye, hold the retinoscope in your left hand
To help stabilize the retinoscope and maintain alignment:
A. Rest it against your brow or spectacle frame
B. Rest the handle against your cheek
C. Rest your elbow on the exam chair arm rest
D. Rest it against the phoropter
A. Rest it against your brow or spectacle frame
If your patient is not dilated for retinoscopy, instruct him to look at:
A. Your nose
B. The retinoscope light
C. A target on the near card
D. A target on the distance chart
D. A target on the distance chart
If your patient is fully dilated for the retinoscopy, you should:
A. Evaluate the full reflex
B. Concentrate on the peripheral portion of the reflex
C. Concentrate on the central portion of the reflex
D. Instill dilation drops until the pupil is 3 mm
C. Concentrate on the central portion of the reflex
In streak retinoscopy, if the streak is vertical, you should:
A. Sweep the streak up and down
B. Sweep the streak left to right
C. Sweep the streak in a circle
D. Turn the streak to the horizontal
B. Sweep the streak left to right
In your initial retinoscopy evaluation (using the proper working lens), you note that the patient has “against” motion in every meridian. This indicates:
A. Myopia
B. Hyperopia
C. Mixed Astigmatism
D. Compound hyperopic astigmatism
A. Myopia
In you initial retinoscopy evaluation (using the proper working lens), you note that the patient has “with” motion in one meridian and “against” motion in the other. This indicates:
A. Simple hyperopic astigmatism
B. Mixed astigmatism
C. Compound hyperopic astigmatism
D. Compound myopic astigmatism
Mixed astigmatism
In your initial retinoscopy evaluation (using the proper working lens), you note that the patient seems to be neutralized already. You should:
A. Record your measurement as Plano sphere
B. Double check for a high refractive error
C. Retinoscopy through the cross cylinder
D. Remove the working lens and check again
B. Double check for a height refractive error
You are working in plus cylinder using a working lens. You see “with” motion at 090 degrees and neutralize this with 1.50 sphere. You now see “with” motion at 190 degrees. Next you should:
A.
