Ophthalmic Optics Test 2

Front 1

The main function of optical aids for low vision is _________, with or without changing the vergence of light.

Back 1

magnification

Front 2

What mag.?: the mag. that results from decreasing the distance of the object from the eye

Back 2

relative distance mag. (bringing it closer than traditional reading distances)

Front 3

an object is brought from 40cm to 10cm. What's the mag.? What reading add does the pt need if they're presbyopic?

Back 3

40/10= 4x; 1/.1= +10D

Front 4

T or F: closer object= larger retinal image

Back 4

T

Front 5

What mag.?: the mag. created by increasing the size of the object, but keeping it at its original distance/position

Back 5

relative size mag.

Front 6

What mag. are these examples of: large print books, magazines, and newspapers?

Back 6

relative size mag.

Front 7

T or F: creating mag. by relative distance mag. does not require additional accommodation, but creating more mag. by relative size mag. does.

Back 7

F!! other way around

Front 8

What is the RSM provided by increasing print size from 12pt to 72 pt?

Back 8

72/12= 6x

Front 9

What mag. is this: mag. resulting from optical or electronic enlargement of image on a screen

Back 9

projection mag.

Front 10

What mag. is projection mag. often used in combo with?

Back 10

relative distance mag.

Front 11

Changing the size of print on an e-book device is an example of what mag.?

Back 11

projection

Front 12

What mag. is this?: mag. produced by an optical system...compares the apparent increase in the size of an object thru the optical system with the size of the object seen without the optical system.

Back 12

angular mag.

Front 13

Afocal telescopes are optical aids for near/distance?

Back 13

distance

Front 14

____: an optical system that provides angular mag. without a change in vergence

Back 14

afocal telescope

Front 15

What telescope is this: positive powered objective and negative powered eyepiece

Back 15

galilean telescope

Front 16

What telescope: the length of the telescope if the secondary focal length of the objective lens minus the primary focal length of the eyepiece

Back 16

galilean

Front 17

For a given mag., which telescope is shorter? Keplerian or Galilean?

Back 17

galilean

Front 18

For a constant mag., increasing the power of the objective and eyepiece produces a longer/shorter telescope.

Back 18

shorter (spectacle mounted needs to be shorter than a hand-held telescope)

Front 19

T or F: a 4x galilean telescope is shorter than a 10x

Back 19

T

Front 20

The image is erect/inverted in the galilean telescope and erect/inverted in the keplerian.

Back 20

erect; inverted

Front 21

T or F: M=-Fe/Fo applies to both the galilean and keplerian telescopes

Back 21

T

Front 22

What telescope: the separation b/w the objective and eyepiece is the sum of the two focal lengths

Back 22

keplerian

Front 23

Galilean:
1. ____ than the keplerian
2. ____ than the keplerian
3. ____ image

(advantages)

Back 23

1. shorter
2. lighter
3. erect

Front 24

Keplerian:
1. ____ than galilean
2. ____ than galilean
3. ____ than galilean

(advantages)

Back 24

1. better image quality
2. greater field of view
3. higher magnification (10x vs. 4x)

Front 25

Why is magnification of galilean telescope limited to about 4x for low vision devices?

Back 25

increasing the mag. decreases the field of view in a telescope that already has a reduced field of view bc exit pupil is between the objective and eyepiece

Front 26

In a myopic patient, which telescope will give them more mag.? What about hyperopic?

Back 26

Myopic: keplerian
hyperopic: galilean

Front 27

What's equation for effective mag.?

Back 27

Meff= M + dMRE/M-1

Front 28

For either telescope:

Separation is decreased for uncorrected ______ and increased for uncorrected _______.

Back 28

myope; hyperope

Front 29

T or F: a 2x telescope makes an object appear twice as large and twice as close

Back 29

T

Front 30

What are the 4 adaptations (problems) a person has to make when using a telescope at distance?

Back 30

the object appears twice as close, increased rate of motion for moving objects, reduced visual field, causes extreme peripheral aberrations

Front 31

If a patient needs a distance telescope but will be playing shuffleboard outdoors all day, what do you recommend?

Back 31

a bioptic telescope (better for people who need them for activities involving movement)

Front 32

Microscopic lenses come in fused bifocals up to _____ and one piece bifocals up to _____.

Back 32

+4.50; +20

Front 33

What's the primary goal of microscopic lenses?

Back 33

allow for relative distance magnification (although there's a small amount of angular mag.)

Front 34

Total magnification of microscopic lenses is the product of what two things?

Back 34

angular mag. and RDM

Front 35

T or F: RDM is measured from the eye

Back 35

T (so you have to take this into account!)

Front 36

A microscopic lens (+8D) is placed 15mm in front of the eye. If this allows the pt to move their reading material from 40cm to 12.5cm, what is the total mag?

Back 36

1. Angular mag= 1+ hF
M=1 + (.015)(8)
M= 1.12
2. RDM= 40/14 (14 bc 12.5+1.5 since it is measured from the EYE) = 2.857x
3. Total= 1.12 x 2.857= 3.2x

Front 37

A patient needs a 2.5x magnifier. What is the power of the lens they will pick up from walgreens?

Back 37

+10D (M=F/4...this uses a 25cm working distance which is the typical reference distance)

Front 38

Aberrations, illumination, centration of lenses and maintenance of proper viewing distance are all problems with what?

Back 38

microscopic lenses

Front 39

If a patient's working distance is less than 10cm using microscopic lenses, how can you relieve the problem of all the convergence demand?

Back 39

use MONOCULAR mag with WD<10cm (aka lenses> +10D)

Front 40

Why do we need to use a reading cap with a telescope at near?

Back 40

bc the accomm demand increases when viewing a near object with a telescope...adding plus lenses in front of the scope relieves this

Front 41

what's a telemicroscope?

Back 41

an afocal miscroscope and reading cap (together)

Front 42

The power of the _________ determines the working distance of the telemicroscope.

Back 42

reading cap

Front 43

What has the shorter working distance:
1. +4 reading cap with 6x telescope
2. +3 reading cap with 8x telescope

Back 43

#1 (1/4<1/3!)

Front 44

Microscopic lenses offer a larger ________ compared to telemicroscopes. Telemicroscopes offer longer _________.

Back 44

field of view; working distances (aka more comfy)

Front 45

What is this: a high plus lens not mounted in a spectacle frame

Back 45

hand magnifiers

Front 46

what is this: plus lens system mounted in a conventional frame with a short vertex distance

Back 46

microscope

Front 47

when the object is at the primary focal plane of a hand magnifier, changing eye to lens distance doesn't effect the _________ but does effect the ________.

Back 47

magnification; field of view

Front 48

Field of view _______ as the hand magnifier is brought closer to the eye

Back 48

increases

Front 49

TQ: When the object is at the primary focal plane of the hand magnifier, is accommodation required?
What about if the object is inside the focal length of the magnifier....is accomm required?

Back 49

NO!; YES (or an add!)

Front 50

when the distance from the (hand) magnifier to the spectacle plane is less than the focal length of the magnifier, the effective power is ___ than that of the magnifier alone.

Back 50

greater

Front 51

the effective power of a hand magnifier is maximum when the magnifier is where?

Back 51

at the spectacle plane (and d is zero)

Front 52

when the distance of the hand magnifier to the spectacle plane is greater than the secondary focal length of the magnifier, then the effective power is ______ than that of the magnifier alone

Back 52

less (but why does the object look bigger when i hold the magnifier farther away?! the answer is APPARENT MAG....only getting bigger because everything else is getting smaller in the surrounding area)

Front 53

when the object is not located at the primary focal plane of a hand magnifier, the FOV is greater if the eye lies where?

Back 53

OUTSIDE the magnifier's secondary focal length

(less if the eye lies inside the magnifier's secondary focal length)

Front 54

for a stand magnifier, where's the object position in relation to the magnifier? what does this require?

Back 54

inside the magnifier's primary focal plane; accommodation (or an add)

Front 55

T or F: the equivalent power of a stand magnifier is the power of a single plus lens held at the spectacle plane that would give the same mag.

Back 55

T

Front 56

for a stand magnifier, increasing d will _________ the equiv power

Back 56

decrease

(conversely, if you decrease d you increase the equivalent power...d=0 means the magnifier is at the spectacle plane and is pretty much a microscope)

Front 57

what are the 3 advantages and one disadvantage of the paperweight magnifier?

Back 57

advan: inexpensive, good light gathering, easy to use

disadvan: relatively low magnification

Front 58

with, for example, a hand magnifier, if the spectacle plane is at the focal length of the magnifier, what is Fe in relation to Fm?

Back 58

they are equal!

Front 59

with, for example, a hand magnifier, if the spectacle plane is further away from the magnifier than its focal length (aka d is larger than the focal length), what is Fe in relation to Fm?

Back 59

Fe is LESS than Fm

Front 60

Occupational vision: primarily concerned with ensuring that the worker has adequate ____ and ____ in order to perform the job in a satisfactory manner. This involves identification of the special ____ ____ or _____ ____ that are required for the performance of a particular job and ensuring that the employee has those______ or has the appropriate _____ ____.

Back 60

skills and aids; visual skills; optical designs; skills; visual aids

Front 61

Role of the optometrist in occupational vision:
1. certify that prospective employees_______________.
2. help an employer __________.
3. determine aspects of the patient's work that may be responsible for _____ _____ or inability to perform their job.

Back 61

1. meet visual standards for occupations
2. establish visual standards
3. visual discomfort

Front 62

T or F: monovision contact lenses are not acceptable for aviation duties

Back 62

T

Front 63

T or F: the vision standards for police officers are mandated by law and must be followed

Back 63

F...they're recommended vision standards

Front 64

the illuminating engineering society recommends task lighting of _____________ ft-candles for more work environments.

Back 64

50-200

Front 65

Glare and uneven illumination increase/decrease blink rate.

Back 65

increase

Front 66

T or F: in workplace design, it is important to keep light sources in the line of sight to avoid glare and reflections

Back 66

FFF...keep light sources away from line of sight (and also avoid glare and reflections, provide even illum, and provide proper luminance levels per IES recommendations)

Front 67

What condition is this: the primary symptoms are eyestrain, blurred vision, dry and irritated eyes, tired eyes, and headaches. Neck and backaches can also be reported.

Back 67

computer vision syndrome

Front 68

T or F: we need to correct low amounts of hyperopia and astigmatism in patients that complain of symptoms assoc with computer vision syndrome

Back 68

T

Front 69

T or F: for computer vision syndrome, we need to correct a patient with minus lenses if they have pseudomyopia

Back 69

F...plus lenses

Front 70

What are the three types of computer glasses we can give to presbyopes?

Back 70

1. single vision intermediate Rx
2. bifocal with top portion for intermediate
3. PAL with wide intermediate zone (soft)

Front 71

Segmented bifocals need to be fit _____ than typical lower limbus position for someone that uses a computer a lot.

Back 71

higher

Front 72

What do you recommend your patient who experiences dry eye with computer use?

Back 72

artificial tears with frequent breaks

Front 73

For the computer user with dry eye, tell them to consider lowering/elevating their screen slightly.

Back 73

lowering

Front 74

For computers with glare, what can improve this? Choices: AR coating on the computer screen or a glare filter

Back 74

glare filter

Front 75

Research indicates that the greatest comfort will occur when eyes are looking __________ 10-20 degrees. For 24 inch viewing distance, center of screen should be ____ inches ____ than the eyes.

Back 75

downward; 4-9; lower

Front 76

Which eyes injury is this (non-industrial or industrial):
1. large objects
2. objects less than 6 mm
3. high velocity objects
4. slow moving objects

Back 76

1. non indus
2. indus
3. indus
4. non indus

Front 77

What are the #1 and #2 causes of broken spectacle lenses?

Back 77

#1 is rocks, #2 is sports

Front 78

T or F: the ANSI safety standard for lenses is .60 ft-lbs which is higher than most forces a lens will encounter including a human fist and a volleyball.

Back 78

F!

Front 79

What lens material is the only one that can adequately resist the high energy impact of both large and small objects?

Back 79

polycarb

Front 80

With OSHA, who must uphold the standards?

Back 80

the EMPLOYER (not us...osha is there for the benefit of the employee)

Front 81

OSHA requires that all industrial eye and face protectors meet the requirements of what? (Rx safety eyewear requires that both frame and lenses meet this)

Back 81

ANSI Z87.1

Front 82

What does the ANSI standard for safety eyewear say about thickness of glasses?

Back 82

Z87.1 says the minimum thickness of glasses must be 3mm (unless its over a +3 lens in which case the edge must be 2.5mm at least)

Front 83

T or F: tints are prohibited for use with safety glasses

Back 83

F

Front 84

T or F: Current OSHA rule does not prohibit the use of photochromic lenses in insutrial safety eyewear

Back 84

T

Front 85

What are the #1 and #2 sports for eye injuries?

Back 85

Basketball, then baseball

Front 86

The only acceptable lens material for sports is what?

Back 86

polycarb

Front 87

T or F: it's better to not wear anything while playing sports than to wear dress eyewear

Back 87

T

Front 88

What are the two biggest concerns with sunglass protection?

Back 88

eliminate harmful portion of the spectrum and maintain dark adaptation (tints of 12-15%) (another one is to maintain normal color vision---only neutral grays absorb wavelengths equally)

Front 89

With aphakic spectacles, ________ retinal image size is a problem.

Back 89

increased (and unilateral mag= aniseikonia)

Front 90

What is this: the field of view for the steadily fixating eye, subtended at the EnP

Back 90

peripheral field of view

Front 91

What is this: the field of view for the moving eye, subtended at the center of rotation

Back 91

macular field of view

Front 92

What creates the ring scotoma in aphakic patients?

Back 92

the decrease in the macular field of view is GREATER than the decrease in peripheral field of view

Front 93

What is the angular size of the gap with a ring scotoma equal to? How do you calculate this?

Back 93

the prismatic effects at the edge of the lens; Prentice's rule (P=dF where d is from the center of the lens to the edge...radius)

Front 94

With a ring scotoma, when the eye rotates inward, where does the scotoma move?

Back 94

outward (jack in the box phenomenon)

Front 95

With ocular rotations in aphakic spectacles, the amount of prismatic deviation depends on the ________ and the _____________________.

Back 95

lens power; angular separation of the two alternately fixated points.

Front 96

What are the two types of aspheric designs that can be used for high plus (>+8) aphakic lenses?

Back 96

continuous and zonal (drop lenses)

Front 97

What distortion do aphakic spectacle wearers experience? How can you control it?

Back 97

pincushion; steeply curved lenses or use of aspheric surfaces

Front 98

What "motion" does the aphakic spectacle wearer experience with their glasses? How can it be avoided?

Back 98

swimming motion (against motion); by moving only the eyes (but this causes distortion)

Front 99

How should you decenter the lenses of aphakic patients so near vision will be better (and what patients is this especially important for?)

Back 99

nasally (so slight BI at distance); patients that are exophoric at near

Front 100

T or F: for aphakic spectacles, we lower the OC .5mm per degree of pantoscopic tilt

Back 100

F!!! we lower the FRAME .5mm per degree of panto tilt (in aphakia we want the frame GC at the OC for minimum lens thickness)

Front 101

To minimize weight of aphakic lenses, we use ____ lenses and ____ eyesize.

Back 101

plastic; small

Front 102

To minimize thickness of aphakic lenses, what do we do?

Back 102

use higher index (also use lenticular design (cosmetic issue for some) and use "knife" edges)

Front 103

To increase the field of view for aphakic lenses, we want to ___ the vertex distance and ___ the lens size. BUT what will this do?

Back 103

decrease; increase; increase the size of the ring scotoma! (although it will push it more towards the periphery)

Front 104

T or F: we MUST provide aphakic patients with UV protection

Back 104

T

Front 105

If the patient has unilateral aphakia, what do we treat them with?

Back 105

contact lens correction (aniseikonia will be an issue with spec correction)

Front 106

What are you more concerned with in lenses for high myopia....weight or thickness?

Back 106

thickness (edge)...if plastic lenses are used then weight isn't an issue

Front 107

What are two ways to reduce minification in myopes with high minus?

Back 107

fit lenses closer to eye and fit contact lenses

Front 108

T or F: minus lenses increase both macular and peripheral fields of view

Back 108

T

Front 109

The problems created by high minus lenses are more _____ than functional.

Back 109

cosmetic (minification of eyes, thick edges, multiple ring effect from thich edges)

Front 110

To minimize edge thickness of high minus lenses:
1. use ___ lens size
2. use frame with frame PD=____
3. use ____ index material

Back 110

1. small
2. distance PD
3. high

Front 111

Lenticular lenses for high myopes will sacrifice _____ and require more _____. When do you use these?

Back 111

field of view; head movement; powers>-10D

Front 112

What are the 6 ways to minimize edge reflections on high minus lenses:
1. edge___
2. edge ___
3. using ____ edge
4. ____ the edge
5. ____ the lens
6. hide-______

Back 112

1. coating
2. painting
3. semitransparent
4. buffing
5. tinting
6. hide-a-bevel