GP and Soft Multifocal (M1) Flashcards
What are the different types of segmented MF lenses?
- fused designs (diff indices of refraction)
- one piece designs (diff anterior surface curvatures for dist and near zones with ledge)
- intermediate zones (look like trifocals)
For the Blanchard Essential lenses, what does changing the series of the lens affect?
- position
- movement
- stability
- fluoroscene
What are the different aspheric back surfaces on a multi-aspheric GP for?
- central aspheric curve provides dist and add
2. peripheral aspheric curve fits peripheral cornea
If a GP lens is riding temporally, what should be done?
- increase lens diameter by 0.5 or 0.3mm
2. specify minus carrier
What should be done to Modified Monovision lenses with distance complaints?
- Decrease add in distance eye
- Eliminate add in distance eye (SV)
- increase minus in distance eye
If poor near vision is occurring in a translating design, what should be done?
- raise seg height
- improve translation
- increase add power
What are the lens types for concentric multifocals?
either center-distance or center-near
What do the single aspheric GPs provide for the patient? 1. How should they be fit (with specific numbers)? 2. What are the effects of these lenses being worn over time? 3
- provides add
- high eccentricity back surface must be fit steep (BC of 1 to 6 D steeper than K, Power 1 to 6 D different than spec Rx)
- mold the cornea to make it more myopic
If a GP lens is riding high, what should be done?
- steepen BC by 0.10mm
- specify thin lens design
- reduce lens diameter
If poor distance vision is occurring in a translating design, what should be done?
- truncate to lower segment
- increase OZD
- lower seg height
What are the advantages to Modified Monovision?
- May allow monovision or multifocal failures to continue wearing CLs
- Better stereopsis than monovision
What are the advantages to multifocal lenses?
- binocularity maintained
- glasses not needed at distance or near
- amblyopia/monocular able to fit
Does an increase in eccentricity increase or decrease power change?
increase
Are aspheric front surfaces better for low or high adds?
low (up to +2.25)
If near vision is decreased due to over-minusing at distance, what is the solution?
carefully OR and push plus
What are the advantages of alternating vision lenses?
- clearer vision at distance and near than with simultaneous designs
- best optics of any multifocal design
What are the advantages to using distance CL and near specs?
- optically clear at distance and near
- cost (less chair time for Dr.)
- cost for patient
What are the key characteristics of a patient that would be best for a simultaneous vision MF lens?
- low lower lid
- looser lids
- accept slight visual compromise
- little residual astig
- usually IP, some LA
What specific types of multifocal lenses are center distance?
- Acuvue Oasys for Presbyopia (Vistakon)
– Proclear EP (CooperVision)
What percent of the time should there be very good vision with multifocal and monovision lenses?
80%
How should a change from an over-refraction be handled by the doctor for a monovision patient?
- use trial lenses
- check change with of proper eye at both near and distance and let them know that this is the change you are g`oing to make to make sure they want it
If poor translation is occurring in a translating design, what should be done?
- flatten BC
- increase prism ballast
- truncate
- raise segment height
What are the key characteristics of a patient that would be best for a alternating vision MF lens?
- large pupil size
- good lid tension
- high add (near) and critical distance
- moderate residual astig
For a simultaneous vision lens, is there more power plus power in the periphery in the center distance or center near?
center distance
What are the presbyopic CL options?
- single vision with over spec
- monovision
- multifocal
When fitting multifocal GP lenses, are monocular or binocular SOR and VA measurements more valuable?
binocular
What is the benefit to multi-aspheric GPs? 1. How should they be fit (with specific numbers)? 2
- more alignment fit and less corneal distortion compared to normal aspheric
- BC of 0.50 to 1.00 D steeper than K and Power 0.50 to 1.00 more minus
If near vision is decreased due to viewing through intermediate and not near zone, what is the solution?
steepen BC or inc OAD (will increase translation) and ensure patient is looking down
What are the advantages of a simultaneous vision CL?
- CL does not have to orient or move in any specific manner
2. easier to fit
How does monovision affect peripheral vision?
it does not
What should be told to a patient that is just receiving monovision for the first time?
- give expectations
- at least 2 weeks of adaptation time
- educate on improvement with time
- caution about night driving
Which should be fitted earlier, multifocal or monovision?
multifocal
Where should the seg line be fit for translating designs? 1. How should the lens be centered? 2
- vertical lens center or at inferior edge of pupil margin
2. slight inferior centration
If distance vision is decreased due to decentration, what is the solution?
steepen BC or increase OAD to center lens
What are the advantages to segmented MF lenses?
- true high add powers available
2. less ghosting, clearer vision
What is the type of CL multifocal that has distinct power zones in the lens that the patient views one or the other depending on the position of gaze with the help of a translating lens?
alternating vision
What should be measured as far as VA’s for a patient with monovision?
measure near and distance for both eyes for medicolegal reasons even though it will be bad for eye that is not properly corrected
What type of design does the Acuvue Oasys for presbyopia have?
combination of concentric and aspheric design
If a GP lens is riding nasally, what should be done?
- increase lens diameter by 0.5 or 0.3mm
2. specify minus carrier
What are the disadvantages to segmented MF lenses?
increased chair time / difficulty of fit (prism ballast, truncation, segment height)
What is the type of multifocal GP that you are able to customize the distance zone and change asphericity on front to generate more add without excessive back asphericity?
Blanchard Reclaim
How many soft aspheric designs should you keep in your practice? 1. GP aspheric designs? 2. GP translating designs? 3
- 2
- 1
- 1
What are the advantages of using monovision?
- ease of fitting
- economical
- glasses not needed
- relatively high success (60 to 80%)
When is the stereo significantly affected when dealing with monovision lenses?
- +1.00 add and higher
- binocular summation for middle and high frequencies lost at +1.50 add
- all binocular summation lost at adds greater than +2.00
How much center thickness is added per 1pd of prism ballast?
0.10mm
What is used in Modified Monovision?
multifocal and single vision lenses
What are the disadvantages of a simultaneous vision CL?
- centration is critical but not always achievable
2. theoretically there is always a blurred image
What should be done to Modified Monovision lenses with near complaints?
- Decrease distance power in near eye
2. Increase add in near eye
If a GP lens is riding low, what should be done?
- increase lens diameter by 0.5 or 0.3mm
- specify minus carrier
- flatten BC by 0.10 (last resort)
What are the disadvantages to Modified Monovision?
Similar to multifocal contact lenses & monovision (cost, time, vision)
What are the disadvantages of using monovision?
- poor option for pt with excessive distance or near tasks
- decreased stereo
- blur at dist and near through opposite eye
- poor intermediate vision in higher add powers
- poor subjective acceptance in higher add powers
- poor option for amblyopes
- adaptation required
What specific types of multifocal lenses are center distance/center near?
– Biofinity multifocal
– Proclear multifocal
What are the disadvantages of alternating vision lenses?
- more challenging fit
- must have inferior lens position: decreased comfort, corneal staining likely
- increased center thickness due to prism ballast
What are the disadvantages to using distance CL and near specs?
- intermediate blur
2. inconvenient
Do GP’s or soft lenses provide better optics?
GP’s
What specific types of multifocal lenses are center near?
– Dailies Aqua Comfort Plus Multifocal (Alcon)
– Proclear 1 Day Multifocal (CooperVision)
– Clariti 1 Day Multifocal (CooperVision)
– BioTrue 1 Day Multifocal (B+L)
– Acuvue 1 Day Moist Multifocal (Vistakon)
– Air Optix Aqua Multifocal (Alcon)
– Purevision Multifocal (B&L)
– PureVision 2 Multifocal
What are the ways to determine the dominant eye of the patient?
- sighting for camera or telescope
- hole in the hand test
- blur acceptance test (eye that accepts more blur is nondominant)
What are the disadvantages to multifocal lenses?
- more complicated to fit/ increased chair time
- high cost
- may still have some visual compromise
