Near Add Determination

What is the difference between testing near VA after refraction, compared to entrance near VAs?

entrance near VAs are binocular

refraction near VAs are monocular

When do you test refraction near VAs binocularly?

if one or both eyes were not 20/20

If your patient is not presbyopic, how would you expect their refraction near acuities to compare to their distance acuities?

should b the same

What are the potential causes of manifest refraction near acuity being worst that manifest refraction distance acuities?

presbyopia

accommodative insufficiency

vergence issues

What is presbyopia?

when the amplitude of accommodation is insufficient to permit sustained, clear, and comfortable vision at customary near working distances

When will a patient theoretically get presbyopia?

when heir amplitude of accommodation is less that required for their working distance

What additional factors are involved in when a patient will get presbyopia?

depth of focus

pupil diameter

print size

What is a rule of thumb for subjective amplitudes?

subjective amplitude is almost double that on objective amplitude

What are the symptoms of presbyopia?

blurry vision at near

eyestrain

tired eyes or feelings sleepy doing near work

difficulty seeing at near in low light conditions

What ways do patients try to adapt to their presbyopia?

hold their reading material far away

increase their font size

increase their illumination for reading

avoid near work

What are ways to determine tentative add?

age determination

plus build up

binocular fused crossed cylinder at near

What are ways to refine the tentative add?

NRA/PRA

Near range of clear vision

trial frame + test drive

What is the tentative add using age determination for a 40 year old?

0 D

What is the tentative add using age determination for a 45 year old?

+1.00D

What is the tentative add using age determination for a 50 year old?

+1.50D

What is the tentative add using age determination for a 48 year old?

+1.25D

What is the tentative add using age determination for a 52 year old?

+1.75D

What is the tentative add using age determination for a 55 year old?

+2.00D

What is the tentative add using age determination for a 60 year old?

+2.25D

What is the tentative add using age determination for a 63 year old?

+2.50D

What is the tentative add using age determination for a 65 year old?

+2.50D

What are the testing conditions when doing age determination tentative add?

phoropter with near PDs pushed in, near card at 40cm, stand lamp illuminating target

If you put in add using age determination and patient isn't reading 20/20, what do you do?

try additional plus

What is plus build up?

add plus binocularly in +0.25D steps from the manifest distance refraction while patient looks at 20/20 (or larger if reduced VA) row of letters on 40cm near card

What are the testing conditions when doing plus build up?

phoropter with near PDs pushed in, near card at 40cm, stand lamp illuminating target

What tentative add test can be used for presbyopes and non-prebyopes?

binocular fused cross cylinder (BCC)

What does the binocular fused crossed cylinder test for in non-prebyopes?

accuracy of accommodation

What does the binocular fused crossed cylinder test for in prebyopes?

tentative add power

What lens power is used for binocular fused crossed cylinder (BCC)?

+0.50-1.00x090

What is the target for binocular fused crossed cylinder (BCC)?

set of vertical and horizontal lines

What does the target look like for binocular fused crossed cylinder (BCC) with the cross cyl lens in place (without +2.00D add)

horizontal lines are sharper and darker

Where is the focus for binocular fused crossed cylinder (BCC) with cross cyl lens in place?

horizontal lines are focused in front of the vertical lines

What is the Goal of binocular fused crossed cylinder (BCC)?

add plus until both horizontal and vertical lines look equally clear

What are the testing conditions for binocular fused crossed cylinder (BCC)?

dim room illumination, stand lamp directed away from target

BCC target set at 40cm

phoropter near PDs in

distance refraction +2.00 D with +/-0.50 cross cyl

Why do we add +2.00D when doing binocular fused crossed cylinder (BCC)??

to bring both line foci in front of the retina

What does the target look like for binocular fused crossed cylinder (BCC) with cross cyl lens and +2.00D add in?

vertical lines will be sharper/darker

Why is binocular fused crossed cylinder (BCC) done in dim illumination?

to keep the pupil big, because a small pupil increases depth of focus

What do you do if the patient responds that the vertical lines look better during binocular fused crossed cylinder (BCC)??

decrease the plus (add minus)

What do you do if the patient responds that the horizontal lines look better during binocular fused crossed cylinder (BCC)??

add more plus

What do you do if the patient reports that there is never a time where both the lines look equal during binocular fused crossed cylinder (BCC)??

leave it at the first horizontal response (first lens that makes the horizontal lines look better)

What does the amount of plus needed to equalize the lines during binocular fused crossed cylinder (BCC) give us?

tentative add

What do you want the end result to be when doing near range of clear vision?

total range:

1/3 in front of 40cm

2/3 behind 40cm

What are the testing conditions for near range of clear vision?

tentative add + near PD in phoropter

near acuity card @40cm with stand lamp on it

What are the steps for the near range of clear vision test?

1. put in tentative add and make sure the patient can read 20/20 clearly at 40cm

2. Move the card closer until the patient reports blur + note the distance (in cm)

3. have the patient look at 20/30 at 40cm

4. Move the card farther away until patient reports blur + record the distance

What do you do if a patient has 1/2 front and 1/2 behind in near range of clear vision?

decrease the add and do additional refinement test

What do you do if a patient has 1/4 in front and 3/4 behind in near range of clear vision??

increase the add and do additional refinement test

What do you do if a patient has 1/3 in front and 2/3 behind in near range of clear vision?

report that as their add

What is negative relative accommodation (NRA)?

The plus power added to relax accommodation at a certain viewing distance

What is positive relative accommodation (PRA)?

the minus power added to increase accommodation at a certain viewing distance

What does NRA measure?

how much accommodation the patient is exerting at 40cm

What does PRA measure?

how much extra the patient could accommodate on top of what they already exerted for 40cm

What are the testing conditions for NRA/PRA?

tentative add in phoropter with PD levers in

stand lamp on 40cm near target (keep these words clear)

What do you always start with when doing NRA/PRA?

NRA

What is your net NRA finding?

the amount of clicks of plus it takes for patient to get sustained blur

Wha is your net PRA finding?

amount of clicks of minus to obtain first sustained blur

What is an ideal end result with NRA/PRA?

equal/opposite powers for NRA/PRA (ex: +0.75/-0.75)

Why do you want the NRA/PRA to be equal?

so the patient has some accommodation to relax to see things further than 40cm, and still has some accommodation they can exert to see things closer than 40cm

What does it mean if there is more NRA than PRA?

add is too weak

What does it mean if there is more PRA than NRA?

add is too strong

What do you do if the NRA/PRA findings are unequal?

take, (NRA + PRA)/2, and add (or subtract) that to your tentative add

What do you do if the NRA/PRA are separated by an odd number of clicks (can't divide by 2)?

demonstrate the +0.25/-0.25 difference to the patient and let they select

When are good examples to use a trial frame evaluation?

if considering a change of refraction

if giving a first time add

if giving a rx for a specific task

What must you warn the patient of if doing a trial frame refraction for refining the add?

distance vision will look horrible + blurry

What are the spec options for presbyopia?

flat, round top, or executive bifocals

trifocals

PALs

single vision readers

What are the CL options for presbyopia?

aspheric

multifocal CL

translation bifocal RGPs

monovision

What are the surgical options for presbyopia?

cataract surgery or clear lens extraction with:

monovision, multicfocal or accommodating IOLs

Lasik for monovision

What presbyopic CL option should only be used for very early presbyopes?

aspheric CLs