Contact Lens 1-2: Presbyopic SCL Fitting Flashcards
What is the largest untapped segment of the CL market?
a. Why?
Presbyopia
a. Steady increase in peeps over 60. 8% in 1950; 11% in 2009; and expected to hit 22% in 2050
3 Options for Presbyopes
- Distance SCL w/Reading Glasses
- Monovision SCL
- Multifocal SCL
Distance SCL w/Reading Glasses
- Number of Focal points?
- Best for what type of wearers?
- Con?
- Pro?
- What options are there?
- Pt stay Binocular or Monocular?
- 2
- Bifocal wearers or those w/o Significant Intermediate Needs
- Doesn’t get rid of the need for Glasses
- Easy Fit
- Toric Options
- Pt stays Binocular
Monovision SCL
- What is it?
- Visual System can alternate what?
- Correction of 1 eye for DISTANCE and the other for NEAR
2. Central Suppression as needed
How does monovision work?
- Which eye is fit for Distance?
- Which is fit for near?
- How does it work?
- Dominant Eye usually
- Non-Dominant (Distance Rx + Near Add)
- a. Interocular Blur Suppression
b. Pt Learns which eye to use for which task (“brain”)
c. Suppresses Dominant Eye when reading
d. Suppresses Non-Dominant Eye when viewing at distance
Acuity In Monovision
- What happens to it?
- What is lost?
- about 1 letter loss in Binocular DVA per DIOPTER of ADD POWER
- Loss in Stereoacuity DIrectly Proportional w/Increasing Add Power
Drawback to Monovision
- 3 drawbacks?
- Success rate?
- a. Stereopsis reduced
b. Contrast loss and difficulty suppressing bright images against a dark background
c. Glare - varies from 67-86%
Approach to Monovision
- 2 ways to determine Dominant eye?
a. When determining Dominance, what needs to be done?
- Triangle Test and Swinging Plus Test
a. Pt HAS to be FULLY corrected for Distance
Triangle Test
- How is it done?
- Hold hands at arm’s length; form triangle w/thumbs at the bottom; Center 20/30-20/40 letter at distance; Close 1 eye then the other; and the eye that can STILL SEE THE TARGET when the other is closed is the DOMINANT EYE!
Swinging Plus Test
- How is it done?
- How do you tell which eye is MORE DOMINANT?
- Use 20/30 to 20/40 letter at distance then Swing +2.00 DS trial lens back and forth from right to left eye
- Eye that’s MOST BLURRED from the +2.00 DS loose lens being in front of it is the DOMINANT EYE
What other ways are there to determine Ocular dominance?
- Eye you put up to a camera
- Eye you Shoot with
- If you have unequal BCVA, the eye w/better BCVA is the dominant.
Near Eye Selection
- % of cases where near eye is the Non-dominant Eye?
- Start w/which eye as the NEAR EYE?
- When do we consider switching?
- 95%
- Non-dominant
- when adaptation is difficult
Adaptation to Monovision
- How long does Full adaptation usually take?
- May take as long as…?
- Difficulties may include what 3 things?
- 2-3 wks (counsel on activities that should be initially avoided)
- 4-6 wks
- Blur, Eyestrain, Headaches
Over-Refraction in Monovision SCL
- 2 things that you can use…?
- Trial Lenses or Flippers
Over-Refraction in Monovision
- Check vision how?
a. What do we expect to see reduced? - How do we over-refract?
- At DISTANCE and NEAR Monocularly AND Binocularly
a. reduced Monocular DVA in non-Dominant Eye and reduced Monocular NVA in Dominant Eye - In Free space and Over-refract MONOCULARLY (Present Lenses to DOMINANT EYE for Distance…and Non-Dominant eye for NEAR)
Verifying Whether a Change Needs to be Made
- Depends on Patient’s what?
a. Incorporating what?
b. ANY CHANGES TO BE MADE SHOULD BE VERIFIED at what?
- visual needs (Prioritization)
a. a +0.50 over-refraction into the Non-dominant eye’s SCL Rx
b. at BOTH DISTANCE and NEAR
To Determine a Patient’s Effective Add
- Effective Add: What is it?
- Over-refract which eye?
- The amt of reading add that the patient is getting in their lenses
- the NON-DOMINANT eye MONOCULARLY at DISTANCE!
(I.e. if patient takes a -1.00 DS over their non-dominant eye MONOCULARLY to get from 20/40 to 20/20 at distance, their effective add is a +1.00 w/their current SCL)
Should Pilots wear Monovision CLs?
- NO! It’s PROHIBITED by the FAA
Depth Perception with Monovision
- Decrease in Stereopsis: By how much?
- Decrease in Stereo increases with what?
- % of monovision patients that report problems with night driving?
- Who is a Liability to fit in Monovision?
- b/w 37-150 seconds of arc
- with Increasing Add Power
- 80%
- Anyone w/Critical Depth Perception Requirements
What 3 things need to be done and Documented in regards to Monovision SCL Wearers?
- Educate pt on Adaptation Period to Monovision
- Educate on Loss of Contract Sensitivity, decrease in Depth Perception and increase in glare at night
- Prescribe a Pair of Glasses to wear over the CL for driving when finalizing the CLRx
Multifocal/Bifocal SCL
- Most are of what design?
a. What does this mean?
b. They can be 1 of 2 things? - There’s also an ALTERNATING VISION (TRANSLATING) design: what is it?
- SIMULTANEOUS VISION Design
a. there’s a focused image and an out-of-focus image on the retina at one time.
b. Center distance or Center Near - Only a Focused image on the Retina at one time.
Multifocal SCL
- 4 Types
- Concentric
- Aspheric
- Combo Concentric/Aspheric
- Diffractive (None on the market today)
Aspheric Designs
- How are they centered?
- Can be DISTANCE or NEAR Centered; depends on brand…some use 1 over the other, and some use both
Aspheric Designs that use BOTH Distance and Near Lenses
- What are they?
- Proclear Multifocal
2. Biofinity Multifocal
Near-Centered Aspheric Designs only
- What are the 2?
- Air Optix Aqua Multifocal
2. Purevision 2 Multifocal
Biofinity Multifocal Fitting Guide
- Add Power
a. +1
b. +1.50
c. +2.00
d. +2.50
- Dominant/Non-Dominant Eye
a. D/D
b. D/D
c. D/N
d. D/N
Air Optix Multifocal Fitting Guide
- Select Initial Lenses
a. Then determine what things?
b. Choose Add based on what?
- a. Vertex-corrected, Least minus/most plus, spherical equivalent distance Rx
b. Lo, MED, HI based on chart: over BOTH EYES
Lo: Up to +1.25
MED: 1.50 to 2.00
HIGH: 2.25 to 2.50
Concentric/Aspheric Design
- What is it?
- What company makes it?
- Hybrid of the 2 designs
2. Acuvue Oasys for Presbyopia
Simultaneous Vision Design
- Regardless of whether they’re concentric, aspheric or combination concentric/aspheric can be the following:
1. Center Distance (3)
2. Center Near (4)
- a. Acuvue Oasys fro Presbyopia (Vistakon)
b. Biofinity Multifocal D Lens (Coopervision)
c. Proclear Multifocal D Lens (Coopervision) - a. Air Optic Multifocal (Ciba/Alcon)
b. Purevision 2 Multifocal (Bausch + Lomb)
c. Proclear Multifocal N Lens (Coopervision)
d. Biofinity Multifocal N Lens (Coopervision)
Challenging Multifocal SCL Patients
- Pupils smaller than what?
- What other 2?
- smaller than 3 mm
2. Emmetropes and Peeps who don’t want to Compromise any of their distance vision
What about Astigmatism?
- Most designs Can’t be used for patients with more than what?
- Only 1 Toric Multifocal SCL on the Market: What is it?
- Custom ones?
- with > 1.00 DC
- Proclear Multifocal Toric (Coopervision)
- Custom Toric Multifocal SCL Available
Multifocal/Bifocal SCL
- Most are SIMULTANEOUS VISION design: What 3 things?
- There are also what designs?
- Aspheric, Concentric, and Combo Concentric/Aspheric
2. Alternating Vision (Translating) Designs
What’s the Alternating Vision Design?
What is it?
Distance at top half of CL and Near at bottom half. (Only 1 Translating SCL on the Market)
*Primary Gaze uses DISTANCE and DOWN GAZE uses Near
Translating CLs
- Good for what kind of patients?
- Who shouldn’t use them?
a. Which LID has the MOST EFFECT on TRANSLATION?
- w/Lower Lid position below the Limbus and/or Loose lids are not good candidates
- Loose lids don’t allow a lens to translate
a. UPPER LID; Lower lid accounts for 1mm of the total translation
Multifocal SCL: 2 groups
- Simultaneous Vision
a. Aspheric (Center distance or Center Near)
b. Concentric (Center Distance or Center Near)
c. Diffractive - Alternating Vision/Translating
Fitting Multifocal SCL
- How is it done?
- Choose Lenses according to manufacturer’s fitting guide;
- Place diagnostic Lenses on Patient’s Eyes
- Let the Lenses Settle
- Check Vision/Over-Refraction
- Check Fit
Simultaneous Multifocal SCL Vision
- Check vision how?
- At Distance and Near Monocularly and Binocularly
* May have reduced mono distance vision in eye w/HIGHER ADD POWER or Center-Near Design and in Near Vision in eye with LOWER ADD POWER or Center-Distance Design
Over-Refracting in Multifocal SCL
- Over-Refract how?
- Some designs call for Over-Refraction how?
- Any changes to be made should be verified how?
- in FREE SPACE!!
- BI-OCULARLY at distance and near Separately (Bi-ocularly –> Both eyes are open but loose lenses or flippers are presented over one eye only)
- Both at DISTANCE and NEAR
Refracting Bi-Ocularly
- How is it done?
- Both Eyes Open; Loose Lens or Flipper over ONE EYE ONLY!!
Verifying whether a Change needs to be made
- Assess what?
- Most important vision is what?
- Patient’s Visual Priorities
- is OU VISION
(e. g. Incorporating a -0.50 over-refraction into the dominant eye’s SCL Rx to improve distance)
Trouble Shooting
- Poor Distance Vision
a. Check for what? - Poor Near Vision
a. Do what?
- a. Check for Underminusing at distance (esp in DOMINANT EYE)
b. Reduce Add in Dominant Eye
c. Uncorrected Cyl??
- a. Push PLUS at distance (esp. in non-dominant eye)
b. Increase the add in the non-dominant eye
c. Uncorrected Cyl?
- Language…Use what terms?
2. Avoid what terms?
- Balance and Prioritizing
2. Compromise or Sacrifice
Creative Combinations
- Modified Monovision
- What else?
- Single vision SCL in dominant Eye and Multifocal SCL in non-dominant eye; Fitting monovision by correcting dominant eye for distance and the non-dominant eye for intermediate
- a. Fitting a different brand of multifocal SCL in each eye
b. Only wearing a lens in 1 eye (Multifocal or single vision)
c. Distance SCL w/Intermediate Glasses
d. Distance SCL w/”Computer PAL”
Presbyopic Correction Success? (3)
- Cosmesis is an issue
- Spectacles are bothersome
- Visual demands are not very critical
- Monovision: Pros/Cons
- Decreased Stereo
a. Not for every occupation
b. Always Prescribe Overglasses for Driving
- Multifocal: Pros/Cons
- Better stereo but depends on lens design
a. Flexible patient
b. Determine Patient’s primary visual demand
Distance SCL w/Overglasses: Pros/Cons
- No intermediate with NVO
- Taking glasses on and off
- For patients w/critical visual demands and no cosmetic concern
