2 - assessment of accommodation

what tests are used to assess accommodative amplitude?

1. push-up or pull away test

2. minus lens test

3. dynamic ret

what tests are used to assess accommodative facility?

lens flippers

what tests are used to assess accommodative response?

1. MEM

2. Nott

3. auto refractive

can you predict results of one test based upon the results of another?

NO

what is the endpoint for push-up test?

first sustained blur

what is the parameters for push-up test?

1. hold in place on forehead

2. 20/30 target

3. 1-2 cm/sec

What is a downside of push-up accommodative amp testing?

overestimates AA

why is the AA lower in minus lens testing?

lens minification

what must you account for when doing minus lens testing at near?

working distance

ex: if pt accommodates through -6 at 40 cm → AA = 8.5 D

how does AA compare with dynamic ret compared to push-up test?

greater than push-up

What is the expected amplitude of accommodation formula?

18.5 - (0.3 x age)

What is the minimum amplitude of accommodation formula?

15 - (0.25 x age)

What amp of accommodation is considered accommodative insufficiency?

if 2D below minimum

what is accommodative facility an indirect measure of?

sustaining ability

what can be reduced in the presence of normal AA?

accommodative facility

what can improve accommodative facility?

VT

what type of measurement is far near vs lens flippers?

far near: qualitative

lens flippers: quantitative

what uses a suppression check, far near or lens flippers?

far near: NO

lens flippers: yes

what are the parameters for testing accommodative facility?

1. accommodative rock card

2. 20/30 letters → target on near point rod

3. time down from 1 min

what is the flipper power and age group for binocular accommodative facility?

8-12 years old

±2.00 at 40 cm

At what age do you use binocular amplitude scaled testing for accommodative facility?

13-30 years

how to demo the suppression check in binocular testing?

1. ask if either bar goes dark

2. patient should understand it can happen with both eyes open

how should the letters look with the polaroid bar reader?

clear and single

what instructions do you tell a child vs an adult when testing accommodative facility?

children: read letters → watch behavior

adults: say 'now' or read letter when single and clear

what is one cycle of accommodative facility?

clear plus and minus

what lens type should you start with for accommodative facility testing?

plus

what should you monitor during accommodative facility testing?

1. rate

2. whether one lens is more difficult

what is the expected value for binocular accommodative facility in 8-12 year olds?

5 cpm

what is the expected value for binocular accommodative facility in 13-30 year olds?

10 cpm

what is the expected value for binocular accommodative facility in 13-30 year olds using a +/- 2.00 lens?

8 cpm

what lens do you use to test 8-12 year old binocularly/monocularly and 13-30 year olds monocularly (accommodative facility)?

±2.00

what is the expected value for monocular accommodative facility in 8-12 year olds?

7 cpm

what is the expected value for monocular accommodative facility in 13-30 year olds?

11 cpm

How should monocular accommodative facility compare between the two eyes?

should be within 3cpm of each other

What is considered a high fail for accommodative facility in adults?

>3cpm but

what is considered a low fail for accommodative facility in adults?

What 2 actions are being assessed with plus lens during accommodative facility?

1. relax accommodation

2. PFV

What 2 actions are being assessed with minus lens during accommodative facility?

1. increase accommodation

2. NFV

what are reasons for difficulty with plus lenses?

1. poor relaxation of accommodation

2. poor PFV

what are reasons for difficulty with minus lenses?

1. poor ability to exert accommodation

2. poor NFV

what do you do if binocular facility is reduced?

test monocular facility

what does it mean if binocular and monocular facility is reduced?

accommodative dysfunction (reduced accommodative facility)

what does it mean if binocular facility is reduced but monocular facility is normal?

vergence dysfunction

where is the near target for MEM dynamic retinoscopy?

at plane of retinoscope aperture → no need to correct for examiner's working distance

what are you finding with MEM dynamic retinoscopy?

determine power of lens that moves position of the near point to coincide with plane of near target

what does neutrality indicate for MEM?

pt is focused at plane of near target

what does with motion indicate for MEM?

pt is focused behind target

lag of accommodation or under accommodation → add plus

what does against motion indicate for MEM?

pt is focused in front of near target

lead of accommodation → add minus

what is the power of lens for MEM?

amount of lag or lead

what do you do if no lens shows neutrality for MEM?

take avg of lens that showed with motion and lens that showed against motion

what are the parameters for MEM?

1. full distance Rx

2. normal room illumination

what is the working distance for MEM?

adults: 40 cm

children: Harmon distance or 33 cm

how quickly do you place lens in front of eye for MEM?

what are the parameters for Nott?

1. target fixed at reading distance

2. normal room illumination

3. examiner moves to find where reflex is neutral

what is the expected value for accommodative accuracy?

+0.50 D ± 0.25 D

what are the reasons for a less plus (a lead) than expected (over accommodation) accommodative response value?

1. accommodative excess

2. high XP and poor positive (BO) fusion range

what are the reasons for a more plus than expected (under accommodation) accommodative response value?

1. accommodative insufficiency

2. high EP and poor negative (BI) fusion range