Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

OT > Amplitude of Accommodation > Flashcards

Amplitude of Accommodation Flashcards

1
Q

What is amplitude of accommodation

A

the dioptric distance between far point and near point of accommodation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is far point

A

point conjugate with the retina of the unaccommodated eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the near point

A

point conj. with retina of max accomm eye (for objective amplitude) OR closest distance that can be seen cearly (for subjective amplitude)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The equation for amplitude says

A

AMPL = FAR PT (D) - NEAR PT(D)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

If an uncorrected 3D myope has a near point of 25cm, what is the amplitude

A

AMP = -3 - (-4)
AMP = 1D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 5 methods to measure amplitude of accomm

A
  1. push up
  2. push down
  3. push away
  4. minus lens (ML)
  5. objective techniques (dynamic ret and autorefractor)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is push up

A

a target is pushed towards the pt until they report first sigh of sustained blur (FSSB)
- this represent pt near point
- when pt is corrected near pt = amplitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how can the push up technique be measured

A

OD, OS and binocular OU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is target size relevant

A

change in target size = change in ability to notice blur
- lowering target size = increased blur detection = decreased amplitude .. occurs in PUSH UP
- increasing target size = decrease blur detection = increased amplitude .. occurs in MINUS LENS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

according to snellens fraction m the patients near point can also be

A

the viewing distance, numerator of fraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the push down technique

A

similar to push up, the target it brought towards the pt until full blur > push away until fully clear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

typically the responses of push up are

A

over estimate of the actual amplitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

typical responses of push down are

A

under estimate of the actual amplitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is push away amplitude

A

placing target close to pt eye, ensure blur > push target away from eye until they can identify the target (not fully clear)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Whats the 2 major problems with push away amplitude

A
  1. end point is when the subject can notice the target, which is not first point of blur > most likely target is farther than needed
  2. children have high amplitudes, hard to make large jumps
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is minus lens amplitude

A
  • target is at 40cm (2.5D)
  • minus lenses added over distance Rx until response for FSSB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the amplitude equation say

A

amplitude = 2.50 + added ML before blur
where 2.5D is the AS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

each diopter of minus lens power increases the accommodative stimulus by

A

1.00D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How can the minus lens amplitude be measured

A

monocularly only

20
Q

what is proximal accommodation

A

assists to find max accommodation, proximal accommodation should be increased

21
Q

what happens to proximal accommodation during minus lens amplitude

A

stays constant

22
Q

what happens to proximal accommodation during push up

A

increases

23
Q

What is positive relative accommodation (PRA)

A

An increase in accommodation while the vergence remains constant

24
Q

How is PRA measured?

A

adding minus lenses binocularly

25
Q

which measurement of amplitude is more favorable, objective or subjective

A

Objective - measuring the point conjugate with the retina where the pt exerts maximum accommodation

26
Q

what are considered objective techniques

A

dynamic ret
autorefraction

27
Q

what are considered subjective techniques

A

push up
push away
push down

28
Q

what is always true about the relationship between objective and subjective amplitdue

A

objective is always < subjective due to blur

29
Q

how do you determine when blur will be reported

A

when AS - AR > half (DOF in Diopters)

30
Q

Based on Duane’s table, what amplitude does a 40 year old have

A

5.5

31
Q

Hoffstetter Eq: for minimum expected amplitude =

A

15 - 0.25 * (age in yrs)

32
Q

Hoffstetter Eq: for mean expected amplitude

A

18.5 - 0.3 * (age in yrs)

33
Q

Hoffstetter Eq: for maximum expected amplitude

A

25 - 0.4 * (age in yrs)

34
Q

the findings of Duanes are based on what kind of accommodation ?

A

accommodative stimulus (AS), a subjective amplitude

35
Q

what are the clinical measurements of accommodative response

A

Dynamic Ret (cross -Nott)
dynamic cross cylinder
near duochrome

36
Q

What is dynamic cross cylinder

A

a subjective test to quantify the lead or lag of accommodation
- corrects the pt for distance
introducing a +/- 0.50 JCC, negative axis vertical over their distance rx

37
Q

if a patient has a LAG of accommodation, which FL is closer to the retina

A

HFL are closer, thus they appear clearer to them
AR < AS

38
Q

In dynamic cross cylinder , plus spheres are added until

A

the two sets of lines appear equal (COLC on retina)

39
Q

the amount of plus added to achieve equality equals

A

lag of accommodation

40
Q

if a pt has a LEAD of accomm. which FL will be closer to the retina

A

VFL are closer to retina, thus appears clearer to pt
AR > AS

41
Q

the amount of minuses added to achieve equality equals

A

the lead of accommodation

42
Q

what happens when a pt accomm. accurately on the target

A

AS = AR
VFL and HFL are equidant from target, both lines appear clear

43
Q

how is dynamic cross cylinder measured

A

binocular and monocularly

44
Q

what age qualifies for accurate dynamic cross cylinder measurement

A

35yr old +

45
Q

for near ducochrome test what does pt response of green and red mean respectively ?

A

green = lag of accom
red = lead of accom

46
Q

what is duochrome testing measuring vs. not ?

A

helps identify the presence of lead and lag but not the measurement of how significant it is

OT (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions