Visual Optics Test 2

Front 1

cataract

Back 1

opacification of the crystalline lens in the eye

Front 2

types of cataract surgerys

Back 2

extra-capsular: nucleus and cortex removed from capsule, leaving posterior capsule, peripheral part of the anterior capsule and the zonules intact

intra-capsular: whole lens removal

Front 3

Phakia
Aphakia
Pseudophakia

Back 3

Phakia: with natural crystalline lens
Aphakia: w/o natural crystalline lens
Pseudophakia: IOL implant following surgery

Front 4

what schematic eye model is used for a aphakic eye

Back 4

Gullstrand's Simplified Schematic Eye

Front 5

how do you treat aphakia with spectacles

Back 5

high plus lens
contact lens

Front 6

what is ring scotoma? what does it treat?

Back 6

edge of plus lens act as a prism
object located in the shadowed areas are not seen

used to treat aphakia with spectacles

Front 7

what is the jack in the box phenomenon

Back 7

associated with the ring scotoma

1. a patient turns head to see an object
2. object disappears in the peripheral of the ring scotoma
3. object then reappears once the image is in the visual area

Front 8

spherical aberration effect of high plus lens

Back 8

mag. of image is more at the peripheral than in the center of the lens due to prismatic effect

object appears stretched out at the corners like a pin-cushion

Front 9

presbyopia

Back 9

a decline in accommodative ability that occurs normally with age and necessitates a plus lens addition to perform near task

Front 10

what to the 4 classification of presbyopia

Back 10

incipient
functional
absolute
premature

Front 11

how does the lens change throughout lifetime

Back 11

1. axial thickness of the lens increase with age
2. radius of curvature of the central anterior surface decreases with age

Front 12

in clinic how much accommodation should the patient sustain on their own

Back 12

up to half

Front 13

what are four ways to treat presbyopia

Back 13

spectacle lens
contact lens
special IOL
surgery

Front 14

what are some classical reasoning for presbyopia

Back 14

crystalline lens hardening reducing the efficiency of the ciliary muscles

crystalline lens gets larger throughout lifetime

Front 15

Isometropia

Back 15

equal refractive errors between the two eyes

Front 16

Anisometropia

Back 16

unequal refractive errors between the two eyes

Front 17

Antimetropia

Back 17

one eye is myopic and one eye is hyperopic

Front 18

when does Anisometropia occurs

Back 18

developmental
ocular surgeries (monocular cataract surgery)

Front 19

what is Aniseikonia

Back 19

1. a difference in image sizes and/or shape seen by the two eyes
2. cause distortions of binocular space perception

Front 20

what is Asymmetric regression

Back 20

if the patient is far-sighted to begin with, one eye may achieve the appropriate correction (or become myopic in that eye) while the other eye may regress back to hyperopia

Front 21

what percent difference can a human fuse an image

Back 21

1-6%

above 6% suppression of eye or diplopia

Front 22

how do you calculate RELATIVE SPECTACLE MAGNIFICATION (RSM) for a distant object

Back 22

RSM =
corrected image size (ametropic eye)/image size of the emmetropic eye

Front 23

Knapps Law

Back 23

A spectacle lens placed at the anterior focal point of any axial ametrope (myope or hyperope) will produce retinal images of the same size.

Front 24

Clinical Corollaries of Knapp’s Law: To reduce interocular differences in retinal image size

Back 24

1) If a patient has an axial anisometropia, correct the patient with spectacle lenses. (AS)

2) If a patient has a refractive anisometropia, correct the patient with contact lenses. (RK)

Front 25

AXIAL ametropia correction with SPECTACLES, what is the relationship between SM and RSM for myopes and hyperopes

Back 25

Hyperope
SM > 1.0; RSM = 1.0

Myope
SM <1.0; RSM =1.0

Front 26

AXIAL ametropia correction with CONTACT LENSES, what is the relationship between SM and RSM for myopes and hyperopes

Back 26

Hyperope
SM = 1.0; RSM < 1.0

Myope
SM =1.0; RSM >1.0

Front 27

REFRACTIVE ametropia correction with CONTACT LENSES, what is the relationship between SM and RSM for myopes and hyperopes

Back 27

Hyperope
SM = RSM = 1.0

Myope
SM = RSM = 1.0

Front 28

REFRACTIVE ametropia correction with SPECTACLES, what is the relationship between SM and RSM for myopes and hyperopes

Back 28

Hyperope
SM = RSM > 1.0

Myope
SM = RSM < 1.0

Front 29

what is Accommodation

Back 29

the ability of the eye to change its refractive power by altering the shape of its crystalline lens to bring objects of interest at different distances into focus.

Front 30

what happens anatomically in the UNACCOMMODATED eye

Back 30

the ciliary muscle is relaxed, the suspensory zonules of Zinn is at its greatest tension, and the lens takes its flattest curves

Front 31

what happens anatomically in the ACCOMMODATED eye

Back 31

a contraction of the ciliary muscle causes a release of resting zonular tension and a decrease in the lens equatorial diameter allowing the young lens to take a more convex form

Front 32

what is Spectacle Accommodation

Back 32

Accommodative amplitude or demand is measured with respect to the spectacle plane (phoropter)

Front 33

what is Ocular Accommodation

Back 33

Accommodative amplitude or demand is measured with respect to the eye’s principal plane

Front 34

what is Range of Accommodation

Back 34

It is the linear distance between the far point and the near point of accommodation.

Front 35

what is Amplitude of Accommodation

Back 35

the amount of accommodation exerted in diopter power to move the focus from the far point to the near point

Front 36

what FOUR things happen to the lens during accommodation

Back 36

1. Decrease radius of curvature, anterior surface decrease more than the posterior surface
2. Increase anterior-posterior thickness -- effective forward displacement of the whole lens; Decrease in equatorial diameter
3. May sink in direction of gravity
4. Increase in lens power causes a decrease in the eye’s focal lengths

Front 37

how do you calculate accommodative amplitude

Back 37

accommodative amplitude= (far point vergence) - (near point vergence)

Front 38

what is Accommodation

Back 38

the ability of the eye to change its refractive power by altering the shape of its crystalline lens to bring objects of interest at different distances into focus.

Front 39

what happens anatomically in the UNACCOMMODATED eye

Back 39

the ciliary muscle is relaxed, the suspensory zonules of Zinn is at its greatest tension, and the lens takes its flattest curves

Front 40

what happens anatomically in the ACCOMMODATED eye

Back 40

a contraction of the ciliary muscle causes a release of resting zonular tension and a decrease in the lens equatorial diameter allowing the young lens to take a more convex form

Front 41

what is Spectacle Accommodation

Back 41

Accommodative amplitude or demand is measured with respect to the spectacle plane (phoropter)

Front 42

what is Ocular Accommodation

Back 42

Accommodative amplitude or demand is measured with respect to the eye’s principal plane

Front 43

what is Range of Accommodation

Back 43

It is the linear distance between the far point and the near point of accommodation.

Front 44

what is Amplitude of Accommodation

Back 44

the amount of accommodation exerted in diopter power to move the focus from the far point to the near point

Front 45

what FOUR things happen to the lens during accommodation

Back 45

1. Decrease radius of curvature, anterior surface decrease more than the posterior surface
2. Increase anterior-posterior thickness -- effective forward displacement of the whole lens; Decrease in equatorial diameter
3. May sink in direction of gravity
4. Increase in lens power causes a decrease in the eye’s focal lengths

Front 46

how do you calculate accommodative amplitude

Back 46

accommodative amplitude= (far point vergence) - (near point vergence)

Front 47

Incipient Presbyopia

Back 47

earliest stage at which symptoms or clinical findings document the near vision effects of the condition

Front 48

Functional Presbyopia

Back 48

When faced with gradually declining accommodative amplitude and continued near task demands, adult patients eventually report visual difficulties

Front 49

Absolute Presbyopia

Back 49

the condition in which virtually no accommodative ability remains

Front 50

Premature Presbyopia

Back 50

Accommodative ability becomes insufficient for the patient's usual near vision tasks at an earlier age than expected due to environmental, nutritional, disease- related, or drug-induced causes