GPs for Presbyopia

1. better optical correction

2. correction of corneal astigmatism

3. GPs translate for cleaner optics

why are GPs good for presbyopia?

1. pt has astigmatism or a higher Rx

2. pt has previously worn hard lenses

3. pt demands the best vision (no visual compromise)

what makes a good GP presbyopia candidate?

concentric, aspheric, translating/alternating

what are the types of GP lenses for presbyopia?

monovision/modified monovision, multifocal GPs, hybrids/sclerals

what are the options for correcting presbyopia w/ GPs?

modified monovision

using a single vision GP lens in one eye for D or N but a MF GP in the other eye

0.50-0.75

is the corneal cyl is w/in ______D of the refractive cyl, we can consider using a GP MF

1. K readings

2. refraction

3. lid position

what pieces of information must be known when fitting a pt in GP MFs?

slight lid control

what type of fit is best for concentrics & aspherics?

rest on lower lid

what type of fit is best for translating designs?

no

will aspheric/concentric lenses be good for pts with high upper lids?

non-rotational

are translating/alternating designs rotational or non-rotational?

rotational

are aspheric/concentric designs rotational or non-rotational?

center distance

most aspheric GPs are what design?

front, back, or both

aspheric MF GPs can have a power change on what surface?

concentrics

have a distance zone & a near zone w/ a sharp transition b/t the 2 zones (like a lined bifocal)

steep central

describe the specific NaFl pattern for back aspherics & concentrics

steeper

the BC will be much ______ than Ks when fitting a back aspheric/back concentric

standard GP fit

describe the BC & diameter for a front aspheric/front concentric

slightly superior to centered w/ some lid control in primary gaze

describe the desired fit for aspherics & concentrics

high

on downgaze, aspheric/concentric lenses will ride _____ to allow the pupil to look through the area of greater add

steeper, smaller

how do you fix an aspheric/concentric lens that is riding too high & is flat?

flatter, larger

how do you fix an aspheric/concentric lens that is riding too low or too tight & does not translate?

1. lens is high on cornea

2. pt has good near vision

3. pt has poor distance vision

what might you see/the pt complain of if the concentric/aspheric lens is riding too high?

1. lens is low on cornea

2. pt has good distance vision

3. pt has poor near vision

what might you see/the pt complain of if the concentric/aspheric lens is riding too low?

1. easy to fit

2. provide good D & intermediate vision w/ reasonable near vision

3. can over plus an eye to boost the near vision

what are the pros of aspheric/ MFs?

1. back aspherics can cause transient corneal warpage

2. near vision may not be great

3. cannot correct residual astigmatism

what are the cons of aspheric MFs?

1. easy to fit

2. good distance & near vision

3. can overplus an eye to boost intermediate vision

what are the pros of concentric MFs?

1. back concentrics can cause transient corneal warpage

2. intermediate vision may not be great

3. cannot correct residual astigmatism

what are the cons of concentric MFs?

alternating/translating GP

• distance zone above

• near zone below

• may have trifocal or progressive power change

• may be truncated or not to help rest on lid

• may have a lip to rest on the lid

great vision due to separate optics

what is the pro of alternating/translating designs?

harder to adapt to due to thickness, increased movement & resting on the lower lid

what is the con of alternating/translating designs?

palpebral aperture, HVID, Ks & Rx

what things are used to fit an alternating/translating GP?

smaller

truncation of alternating/translating GPs is helpful for pts w/ ______ apertures

0.4mm

what is a good starting point for truncation on an alternating/translating GP?

F (start w/o and see if it is needed)

T/F: you should truncate all alternating/translating designs

1. well centered or slightly low

2. 1-2mm of movement w/ blinks

3. 2mm of lens translation on downgaze

4. 5-10deg of usually nasal rotation is acceptable

describe a good fit for an alternating/translating lens design

steep

alternating/translating GPs are usually fit slightly _______

lens moves slowly w/ the blink & falls quickly into position

describe an alternating/translating GP that is fit too flat

lens doesn’t move w/ blinks, there is no translation, & there is definite excessive central vaulting

describe an alternating/translating GP that is fit too steep

at or just above the lower pupil margin

where should the near seg be when assessing fit of an alternating/translating GP?