8.1 Multifocal Lenses

What numerical value is normally when presbyopia starts?

AA < 5D

What is the near power?

distance rx + add

What is the add power?

amount of plus added to distance power

Who will get presbyopia symptoms first?

hyperope, then emmetrope, then myope (in specs)

What is an average first add?

+1.25D

What is the normal add increase?

+0/25 every 2-3 years

What are factors that influence add power?

age

occupation/visual demands

stature/arm length

pupil size

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

+0D

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

+1.00D

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

+1.25

What is the tentative add using age tables for a 50 year olds?

+1.50

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

+1.75

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

+2.00

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

+2.25

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

+2.50

Why do we not give everyone a +2.50 add?

hard adaptation

image jump

BV issues

limited range of clear vision

What is your maximum range of clear vision?

from your far point to using your maximum AA

What is you range of comfortable clear vision?

your far point to 1/2 your AA

What is your max comfortable accommodation?

1/2 AA

Looking through your distance prescription where is the FP?

infinity

Looking through your distance prescription, where is the near point?

1/AA

Looking through your distance prescription, where is the near comfort point?

1/MCA aka 1/0.5AA

Looking through near prescription, where is the FP?

1/add

looking through near prescription, where is the NP?

1/(add + AA)

looking through near prescription, where is the near comfort point?

1/(add + MCA) or 1/(add + 1/2AA)