KMK Precise Practice - Geometric Optics

Where is the object of a collimating lens located?

Infinity

Primary focal point

Twice the focal length

Inside the focal length

primary focal point

A 10° prism deviates light by 5°. What is its index of refraction?

1.6

1.5

1.7

1.4

1.5

d=(n-1)(A)

5=(n-1)(10)

n=1.5

An object is located at twice the primary focal length of a +2.00 D lens. Where will the image be formed?

F'

Extra-focal point

2F'

Infinity

2F'

What is the spherical equivalent of the minus cylinder lens +3.00 DS -2.50 DC x 180?

+0.50 D

+1.25 D

+2.50 D

+1.75 D

+1.75

+3.00 + (-2.50/2)

+3.00 + (-1.25)

+1.75 D.

A spectacle lens has a front surface power of +5.00 D, a back surface power of -7.00 D, a center thickness of 2 mm, and an index of refraction of 1.5. What is the back vertex power of the spectacle lens?

-2.30 D

-2.21 D

-1.97 D

-1.80 D

-1.97

Fv = F2 + (F1 / (1 - (t/n)(F1)))

Fv = (-7.00 D) + (+5.00 D / (1 - (0.002 / 1.5)(+5.00 D)))

Fv = -7.00 D + (+5.03 D)

Fv = -1.97 D.

Which of the following has the shortest wavelength (and the highest frequency)?

Visible light

Microwaves

Radio waves

Ultraviolet light

Gamma rays

gamma

Which of the following has the longest wavelength (and the shortest frequency)?

Visible light

Microwaves

Radio waves

Ultraviolet light

Gamma rays

Radio Waves

A magnification value of +0.90 indicates which of the following?

The image is 90% smaller than the object.

The image is 90% larger than the object.

The image is 10% larger than the object.

The image is 10% smaller than the object.

The image is 10% smaller than the object.

Magnification values are relative to 1, which indicates what?

no magnification or minification

Magnification values smaller than 1 indicate the image is?

minified compared to the object

Magnification values larger than 1 indicate the image is?

larger than the object?

Which of the following characteristics are TRUE regarding the corneal reflex image in keratometry? SELECT 2

Upright

Inverted

Virtual

Real

upright

virtual

Recall the cornea acts as what type of mirror?

Convex (negative) Mirror

Which of the following statements regarding a sphero-cylinder lens are TRUE? SELECT 2

The axis direction is where the cylinder power is at its maximum.

The axis direction is where the cylinder power is zero.

When transposing from minus-cylinder to plus-cylinder, the axis changes by 090⁰.

When transposing from minus-cylinder to plus-cylinder, the axis does not change.

The axis direction is where the cylinder power is zero.

When transposing from minus-cylinder to plus-cylinder, the axis changes by 090⁰.

Panto tilt describes tilt around what meridian?

180

Faceform tilt describes tilt around what meridian?

090

Tilting a plus lens induces what type of cyl?

Plus cyl

Tilting a minus lens induces what type of cyl?

Minus cyl

Pantoscopic tilt of a spherical plus lens induces cylinder power in which axis? Faceform tilt of a spherical minus lens induces cylinder power in which axis (assuming the axis is written in minus cylinder power form)?

90; 180

180; 180

90; 90

180; 90

90,90

What is the equivalent power of a spectacle lens with a front surface power of +5.00 D, a back surface power of -7.00 D, a center thickness of 2 mm, and an index of refraction of 1.5?

+2.50 D

-2.95 D

-1.50 D

-1.95 D

-1.95

What is the power of a concave spherical mirror in air with a radius of curvature of 20 cm?

+5.00 D

+2.50 D

+10.00 D

+20.00 D

+10

Which of the following laser scanning techniques utilizes polarized light to measure the thickness of the retinal nerve fiber layer (RNFL)?

Scanning laser polarimetry

Optical coherence tomography

Optical confocal topography

Confocal scanning laser tomography

Scanning laser polarimetry

The back vertex power of a spectacle lens is the vergence of light that exits the spectacle lens when an object is located at:

F

F'

2F

Infinity

infinity

Which of the following CORRECTLY describes the circle of least confusion?

It is formed by the horizontal principle meridian of a sphero-cylinder lens.

It is the point of best focus for a sphero-cylinder spectacle lens.

It is located at the linear halfway point between the near and far lines.

Its size increases as the magnitude of cylinder power decreases.

It is the point of best focus for a sphero-cylinder spectacle lens.

Which of the following is TRUE regarding polarized sunglasses?

They have a horizontal transmission axis.

They absorb horizontally polarized light.

They act as a phase retarder.

They act as a waveplate.

They absorb horizontally polarized light.

transmission axis is 90

Which of the following light sources produces the MOST coherent light?

Gas discharge lamps

Incandescent bulbs

Sun

Lasers

lasers

Which of the following statements regarding antireflective coatings is INCORRECT?

The index of refraction of the antireflective coating is higher than the spectacle lens.

Antireflective coatings result in an increase in visual acuity.

The thickness of antireflective coatings is dependent on the wavelength.

Interference produced by the antireflective coating helps to reduce glare.

The index of refraction of the antireflective coating is higher than the spectacle lens.

Which lasers are CORRECTLY paired with the procedures for which they are used? SELECT 4

Krypton; PRP

Argon; LPI

Holmium; OCT

Nd:YAG; LPI

Excimer; LASIK

Nd:YAG; ALT

Krypton; PRP

Argon; LPI

Nd:YAG; LPI

Excimer; LASIK

What is the power of a thin lens with a front surface radius of +9 cm, a back surface radius of -8 cm, and n = 1.5 (to the nearest 0.25 D)? Assume the lens is in air.

+8.75 D

+9.75 D

+10.75 D

+11.75 D

+11.75

The critical angle of a surface is 30⁰. What is the corresponding angle of refraction?

0⁰

90⁰

35⁰

95⁰

90

A real object is located 40 cm from a -2.00 D lens. What type of image is produced? SELECT 2

A real image located at F

Upright and magnified

Upright and minified

Inverted and minified

Inverted and magnified

A virtual image located at 2F'

A real image located inside F'

A virtual image located inside F'

Upright and minified

A virtual image located inside F'

Which of the following is the image of the aperture stop formed by the lenses in front of the aperture stop?

Exit pupil

Exit port

Entrance pupil

Entrance port

entrance pupil

A real object is located in front of a minus spectacle lens. How will the size of the image compare to the size of the object?

The image will be the same size.

The image will always be smaller.

The image will always be larger.

the image will be smaller

What is the index of refraction for an ideal thin film that minimizes reflections for a crown glass lens in air?

1.234

1.225

1.523

2.324

take square root of 1.523 = 1.234

A small pupil will decrease visual acuity because of:

decreased coherence

increased diffraction

increased interference

decreased aberration

increased diffraction

Which of the following statements regarding lasers is CORRECT?

Pumping the system creates low energy atoms.

They produce incoherent light.

They produce a small bandwidth.

They contain multiple wavelengths of light.

the produce a small bandwidth

Which of the following cause an increase in the depth-of-field? SELECT 2

Increased pupil size

Increased focal length

Decreased pupil size

Decreased focal length

Decreased pupil size

Decreased focal length

Which of the following is NOT a use for argon laser?

Retinal tear repair

SLT

LPI

PRP

SLT

Where should a real object be placed in relation to a convex lens in order to achieve a magnification of -1?

At infinity

Inside the focal point

At the focal point

At twice the focal point

at twice the focal point

A real object is located 33 cm in front of a concave mirror and produces an image with a lateral magnification of -3X. What is the power of the mirror?

1.00 D

5.00 D

2.00 D

4.00 D

4

A biconvex lens is made from glass. If a lens with identical geometry is made from high index plastic, how do the surface powers of the new lens compare to those of the old lens?

Both surfaces become more positive

One surface becomes more positive and the other becomes more negative

Both surfaces become more negative

None of the above

both surface powers become more positive

A patient with hyperopia is fully corrected with +7.00 D spectacle lenses at a vertex distance of 10 mm. How will the effective power of the spectacle lenses change if the patient now wears his glasses further away from his face?

The effective power will remain the same.

The effective power will increase and the patient will be overcorrected.

The effective power will decrease and the patient will be undercorrected.

The effective power will increase and the patient will be overcorrected.

What is the minimum thickness for an antireflective coating (n=1.60) that is needed to reduce glare caused by 420 nm light?

139 nm

66 nm

87 nm

105 nm

66

A +12.00 D glass lens is worn with 9 degrees of faceform tilt. What is the equivalent (untilted) spherocylindrical lens?

+16.00 DS -0.75 DC x 090

+13.25 DS +0.75 DC x 180

+12.50 DS +0.25 DC x 180

+12.50 DS -0.25 DC x 180

+12.50 DS -0.25 DC x 180

A glass lens (n = 1.5) has a central thickness of 5 mm, a back vertex power of +12.50 D, and a front surface power of +8.00 D. What is the back surface power of the lens?

+4.75 D

+3.75 D

+4.25 D

+4.50 D

4.29

A patient uses a stand magnifier at a distance of 40 cm. The stand magnifier forms an image 25 cm to the object side of the magnifier. How much accommodation is required in order for the patient to clearly see the magnified object?

4.00 D

3.25 D

1.50 D

2.50 D

1.5

Which of the following statements regarding light scatter at the edge of spectacle lenses are CORRECT? SELECT 2

Adding an antireflective coating to the spectacle lenses will minimize external reflection that is responsible for light scatter.

It is primarily due to total internal reflection of light rays on the edge of the spectacle lenses.

It is primarily a result of diffraction due to an increase in power at the edge of the spectacle lenses.

Increasing the thickness of the spectacle lenses will minimize peripheral light scatter.

Choosing a spectacle lens material with a lower index of refraction will minimize peripheral light scatter.

Choosing a spectacle lens material with a lower index of refraction will minimize peripheral light scatter.

It is primarily a result of diffraction due to an increase in power at the edge of the spectacle lenses.

What is the calculated astigmatic interval of a +4.00 DS -2.00 DC x 180 spectacle lens?

25 cm

100 cm

67 cm

50 cm

25

A patient wears +10.00 DS contact lenses OD and OS. What spectacle power would be required at a vertex distance of 12 mm (to the nearest 0.25 D)?

+11.00 DS

+9.00 DS

+8.00 DS

+10.00 DS

9

How does the dioptric depth-of-field change as the object distance from a given plus lens increases?

Decreases

Stays the same

Increases

increases

A lens has a power of +2.00 D in the vertical meridian and +1.00 D in the horizontal meridian. What is the power of this lens expressed in minus cylinder form, and where is the circle of least confusion formed?

+1.00 DS -2.00 DC x 090; 2.00 D from the lens

+2.00 DS -1.00 DC x 180; 1.50 D from the lens

+2.00 DS -1.00 DC x 090; 67 cm from the lens

+2.00 DS +1.00 DC x 180; 50 cm from the lens

+2.00 DS -1.00 DC x 090; 67 cm from the lens

An object is located 100 cm from a spectacle lens with the prescription +6.00 DS -3.00 DC x 180. Where is the circle of least confusion formed?

100 cm

50.0 cm

20.0 cm

28.6 cm

28.6 cm

A patient with uncorrected axial myopia has a blurred retinal image when viewing an object at 40 cm. How does the blurred retinal image change if the amount of axial myopia is increased?

The new retinal image will be equally blurred and will be the same size.

The new retinal image will be larger but equally blurred.

The new retinal image will stay the same size but will be more blurred.

The new retinal image will be larger and more blurred.

The new retinal image will be larger and more blurred.

Which of the following ocular structures have birefringent properties?

Cornea and the retinal nerve fiber layer only

Cornea and the crystalline lens only

Crystalline lens and the retinal nerve fiber layer only

Cornea, crystalline lens, and the retinal nerve fiber layer

Cornea, crystalline lens, and the retinal nerve fiber layer

Which of the following have lower frequencies compared to visible light? SELECT 4

Ultraviolet light

Radio waves

Microwaves

Radar waves

Infrared

X-rays

Gamma rays

Radio waves

Microwaves

Radar waves

Infrared

Which of the following statements regarding scattered light are TRUE? SELECT 4

Mie scattering is caused by atmospheric gases.

Mie scattering affects all wavelengths equally.

Rayleigh scattering is due to small particles in the atmosphere.

Rayleigh scattering explains why the sky is blue.

Mie scattering explains why sunsets in a clean atmosphere are orange/red.

Mie scattering explains why clouds are white.

Mie scattering affects all wavelengths equally.

Rayleigh scattering is due to small particles in the atmosphere.

Rayleigh scattering explains why the sky is blue.

Mie scattering explains why clouds are white.

When does total internal reflection occur on a glass-air interface where nglass = 1.50?

Critical angle = 0 degrees

Critical angle = 41.8 degrees

Critical angle = 90 degrees

Angle of incidence is greater than critical angle

Angle of incidence is greater than critical angle

A patient requires a +10.00 D lens at the cornea to correct his hyperopia. A refraction is performed at some unknown vertex distance and yields +8.00 D. At what vertex distance was the refraction performed?

12.5 mm

22.5 mm

25 mm

10.0 mm

25

A patient views a real object through a +3.00 D magnifier. The object is 25 cm from the magnifier, and the patient is 40 cm on the opposite side of the magnifier. Where is the image formed?

10 cm from the patient

25 cm from the magnifier

33 cm from the magnifier

140 cm from the patient

140

How does the depth of field change if the focal length of a system is increased, or if the aperture size is increased?

increase; increase

increase; decrease

decrease; decrease

decrease; increase

decrease; decrease

A plano-convex lens has a 15 cm radius of curvature and 3 mm central thickness. What is its maximum diameter?

9.5 mm

30 mm

60 mm

19 mm

60

How does the depth-of-focus change if the aperture size of the eye decreases?

Decreases

Increases

Stays the same

Increases

Which wavelength is LEAST likely to reach the retina?

UV-A

UV-B

UV-C

C

If unpolarized light with an intensity of 120 candelas passes through a polarizer, what is the intensity of light that exits the polarizer?

30 candelas

40 candelas

60 candelas

120 candelas

60

A real object in air is located 50 cm away from a single spherical refractive surface with an index of refraction of 1.5. A real image is located 200 cm behind the surface. Which of the following is the magnification (M)?

-3.67

-1.67

-2.67

-0.67

-2.67

An object is located 50 cm from a pinhole placed at the surface of the cornea. The patient's axial length is 2.6 cm. How large is the retinal image that is formed compared to the size of the object?

-19X

-0.04X

19X

0.04X

-0.04X

A real object is located 40 cm from a +5.00 D lens which is 10 cm from a +2.00 lens. Where is the image formed after traveling through this lens system?

about 19 cm from the +5.00 lens

about 19 cm from the +2.00 lens

30 cm from the +5.00 lens

40 cm from the +5.00 lens

about 19 cm from the +2.00 lens