toric%20and%20multifocal%20gas%20permeable%20and%20soft ...the contacts you have now are a...

5/23/2016

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Edward S. Bennett, OD, MS Ed, FAAO (Dipl), FSLSStephanie L. Woo, OD, FAAO, FSLS

Financial disclosures

Dr. Bennett:

Consultant to CLMA

Dr. Woo:

Biotissue

Blanchard contact lens

X-cel contacts

Visionary Optics

Alcon

Bausch and Lomb

Essilor contacts

Specialeyes

What are soft custom lenses?

Contact lenses designed for a truly custom fit

These designs feature:- smaller and larger diameters - wider range of curvatures- wide range of sphere and cylinder powers- exact cylinder axis- custom lens thickness

Custom toric contact lenses correct higher amounts of astigmatism than conventional soft toric lenses.Custom soft multifocals can provide patients with better vision than standard multifocals

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Current trends

Annual Contact Lens update 2012: Many large CL companies discontinued their

wider range of parameters (extended sphere and cylinder powers)

This left a huge need for soft custom lenses Custom torics offer us an opportunity to manage

astigmats in a highly precise way

Nichols, J. Contact Lens Update 2012. Contact Lens Spectrum. Jan 2012.

Custom Soft Torics

Recent studies have suggested that astigmats who are new wearers or previous contact lens dropouts achieve visual acuity comparable to spectacles when fitted with toric soft lenses

Specialty labs produce custom toric soft lenses with expanded parameters that the larger manufacturers are not currently offering.

Dr. Doug Benoit states, “These smaller labs have increased what we can do, so more patients are able to wear toric soft contact lenses than in the past.”

Cole, J. et al. Torics for astigmatism: soft and hard choice. Review of Optometry. July 2013

Candidates for soft custom lenses

High amounts of astigmatism Unhappy with their vision with their current

contact lenses Prescription in current CLs is not exact Lens rotation Fit issues

Good candidates for GP lenses, but concerned about comfort or unwilling to try

Astigmatic presbyopes! Multifocal options are becoming better

Those desiring the best vision

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Custom soft multifocals

Many labs offer new, innovative designs

Most need keratometry values, refraction, add power, eye dominance, HVID, and pupil size

Candidates for custom MF

Patients wearing soft MF with cy>1.00 D

Emerging presbyopes already wearing soft lenses

Monovision patients unsatisfied with vision

Patients wanting to try latest technology

Pros and Cons of Soft Custom Lenses

Pros of Soft Custom Torics Great vision Great fit No need to build up wear

time Stable – lens usually does not

pop out, even with vigorous activity

Truly custom lens Can correct large amounts of

astigmatism Can be an option for

presbyopes

Cons of Soft Custom Lenses Can be expensive

Vision may not be as good as GP lens

Lens replacement is usually quarterly/annually

Cost of lens if lost/damaged

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Rumpakis, J. New data on contact lens dropouts: an international perspective. Review of Optometry. Jan 2010

How to introduce custom soft lenses

If the patient is unhappy with the vision of their current contact lenses or how they feel, try explaining that a more custom lens may be more comfortable and produce better vision.

Example, “Jane, I see why your vision is not as sharp with your current contacts. The contacts you have now are a “one-size-fits all” – meaning that the shape of the lens only comes in one curve, and you may need another shape to fit your eye properly. Also, the standard contact lenses you are in correct most of your prescription, but not all of it. A more custom lens may fit your eye better and give you better vision.”

How to introduce custom soft lenses If a patient has a large amount of

astigmatism and has never worn contact lenses, but expresses interest:

Ex: “I think you are a great candidate for contact lenses. However, you have a large amount of astigmatism. It is more than most standard contact lenses have available. I would recommend a lens that corrects your entire amount of prescription and fits on your eye properly.”

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How are custom soft lenses designed?

Many manufacturers use some sort of fitting nomogram to design the lens

Prescribing Nomograms enable practitioners to quickly design custom soft contact lenses for patients with an average corneal diameter or horizontal visible iris diameter (HVID) of 11.6 to 12.0mm.

Ordering custom lenses is easy!

Many manufacturers only require keratometry values and refraction

For multifocals, you may need add power, eye dominance, and/or pupil size

Giving them Horizontal Visible Iris Diameter (HVID) can assist in providing an even more accurate lensNormal HVID: 11.6-12.00mm

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Keratometry

Refraction

Order!

Ordering is EASY!

Call the lab

Email

Use online tools

So many ways to order!

Pricing

Custom soft lenses can have similar pricing! Ex: Tyler’s Quarterly: Frequency 55 Toric XR: unit cost $73.25 for 6 pack

= $146.50 for year supply SpecialEyes 54% custom toric: $28 for quarterly

lens = $112 for year supply Alden HP toric: year supply (quarterly lens) =$120 Keep in mind this is OUR cost – cost to pt will be

more, but prices are similar or better!

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Other benefits

Quick production and shipping! Customization allows for better vision and fit than

standard lenses Custom lenses CANNOT be ordered online or

through 1-800-_______ Patients can only order through your office

Patient retention Patients know you are on the cutting edge of

technology

Custom soft lenses for irregular astigmatism

Indications: Corneal ectasia ( keratoconus, PMD, etc)

Post refractive surgery

Post transplant

Intolerant to GP lenses

Poor handling with scleral lenses

How it works

Courtesy of Mark Andre and Pat Caroline

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Realistic expectations

Improved comfort compared to corneal GP lenses

Vision not as crisp as GP lenses

Fitting basics

Each design is fit a bit different, but the fitting guide is included in the fitting set

Centration and appropriate touch are important

Check for adequate movement and lens rotation

Tips on fitting and evaluation

After you order custom soft lenses, dispense the lenses in office – do NOT let patients take the lenses without checking vision and fit

Apply the lenses to the patient or have the patient apply the lenses

Pt ed “You’ve never worn these type of lenses before so they might feel a little strange; that is NORMAL”

Let settle for 5 minutes

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Tips on fitting and evaluation

After 5 minutes, assess vision OD, OS, OU (distance and near) and check the fit of the lenses

If vision is 20/30 or better and the fit is acceptable, dispense the lenses and have the patient follow up in 1-2 weeks.

If the vision is not acceptable, check the fit and over-refraction and report results to a consultant

Clinical Pearls

Custom soft lenses provide excellent vision and an excellent fit

Many manufacturers only require K’s and refraction = simple!

Cost can be similar or better than what they are currently wearing

Cannot order these anywhere but your office

Why not give our patients the best lens possible, a truly custom lens!

And when those soft lenses don’t work, there are always gas permeable lens options!

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GPS AND HIGH ASTIGMATISM

With > 2.00D corneal cylinder the following problems can occur with a spherical GP:

• Flexure

• Decentration

• Corneal Warpage

• Corneal Desiccation

• Lens Awareness

BACK TORIC

Determination of Base Curve Radii: (Mandell-Moore)

Corneal Cyl Flat Meridian Steep Meridian2.0 - 2.25D “On K” 0.50D Flat2.5 - 2.75D 0.25D Flat 0.50D Flat3.0 - 3.25D 0.25D Flat 0.75D Flat3.5 - 3.75D 0.25D Flat 0.75D Flat4.0 - 4.75D 0.25D Flat 0.75D Flat≥ 5.0D 0.25D Flat 0.75D Flat

BITORICS

When you correct for induced cylinder i.e., if 3.5 to 3.75D WTR cyl, add +1.75 x 180) on front surface, you have a bitoric design

Provides good centration; should fit like a spherical lens on low astigmatic cornea

Provides good vision Results in good corneal integrity When induced cylinder (only) is corrected, this

results in a spherical power effect

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EMPIRICAL METHODS

Mandell-MooreGPLI Toric and Spherical

CalculatorNewman Guide

Mandell-Moore Case Mandell-Moore Bitoric Lens Guide - Per eye

1 Keratometry

2 Spectacle Rx (Minus Cyl Form)

Flattest K Sphere Steepest K Sph + CylPower Power

3 Enter K4 Enter Spectacle Power

5 Vertex Adjust Line 4 6 Insert Fit Factor (-) (+) (-) (+)

Add Line 3&6 5&6 3&6 5&6

7 Final CL RxBase Curve Power Base Curve Power

Mandell-Moore Case

Corneal Cyl Fit Flat Meridian Fit Steep Meridian

2.0 Diopters On K (0 D) 0.50D Flatter

2.5 Diopters 0.25D Flatter 0.50D Flatter





Bitoric Lens Fit Factor

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1 Keratometry 42.50 @ 180 46.00 @ 90

2 Spectacle Rx (Minus Cyl Form) - 4.00 – 4.00 x 180


3 Enter K4 Enter Spectacle Power

5 Vertex Adjust Line 4

6 Insert Fit Factor (-) (+) (-) (+)

Add Line 3&6 5&6 3&6 5&6

7 Final CL Rx

Base Curve Power Base Curve Power


1 Keratometry 42.50 @ 180 46.00 @ 90



3 Enter K 42.50 46.004 Enter Spectacle Power



Add Line 3&6 5&6 3&6 5&6

7 Final CL Rx



1 Keratometry 42.50 @ 180 46.00 @ 90



3 Enter K 42.50 46.004 Enter Spectacle Power - 4.00 - 8.00



Add Line 3&6 5&6 3&6 5&6

7 Final CL Rx


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1 Keratometry 42.50 @ 180 46.00 @ 90




5 Vertex Adjust Line 4 - 3.75 - 7.25


Add Line 3&6 5&6 3&6 5&6

7 Final CL Rx



1 Keratometry 42.50 @ 180 46.00 @ 90





6 Insert Fit Factor (-) 0.25 (+) 0.25 (-) 0.75 (+) 0.75

Add Line 3&6 5&6 3&6 5&6

7 Final CL RxBase Curve Power Base Curve Power


1 Keratometry 42.50 @ 180 46.00 @ 90





6 Insert Fit Factor (-) 0.25 (+) 0.25 (-) 0.75 (+) 0.75

Add Line 3&6 5&6 3&6 5&6

7 Final CL Rx 42.25 - 3.50 45.25 - 6.50


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Step 7 +/- Fit Factor

-3.75

-8.00

-4.00 42.50

46.00-7.25

0.25 Fit Factor

0.75 Fit Factor

-3.50 42.25

-6.50 45.25

EMPIRICAL METHODS



GPLI Toric and Spherical Lens Calculator: www.gpli.info

Toric and spherical lenses empirically designed

The toric calculator was designed by Dr. Tom Quinn (thank you to Todd Zarwell of Eyedock.com)

When you input refraction and K values it will design a spherical lens with ≤ 2D of corneal cylinder and a toric lens with > 2D of corneal cylinder

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-1.00

-4.00

Contact Lens

OAD: 9.2 mmtear lens

41.00

44.00

41.00

43.25

-1.00

-3.25

plano

-0.75

Rx: -1.00-3.00 X 180

K’s: 41.00/ 44.00 @ 090

Order:BC: 41.00 (8.23mm)/ 43.25 (7.80mm)BVP: -1.00/ -3.25

Difference in lens powers: 2.25D

Conclusion:Spherical Power Effect Design

Difference in base curve (D): 2.25 D

+0.25

-1.50

Contact Lens

OAD: 8.8 mm

43.00

45.25

Rx: +0.25 -1.75 x 180K’s: 43.00/46.00 @ 090

43.00

46.00

LENS DIAMETER BC/CORNEA RELATIONSHIP

HORIZONTAL VERTICAL

Interm.(8.7-9.3mm) ON K 0.75 FTK

tear lens

plano

-0.75

+0.25

-1.50

Contact Lens

OAD: 8.8 mm

43.00

45.25

43.00

46.00

+0.25

-0.75

Difference in base curve (D): 2.25 DDifference in lens powers: 1.00 D

Conclusion: Since 2.25 D does not equal 1.00 D Cylinder Power Effect Design

Rotational Precautions:

1. Is there at least 2D of toricity in base curve?Yes (2.25D)

2. Is base curve toricity at least 2/3rds of corneal toricity?

Yes 3D (corneal toricity) x 2/3= 2D

Okay to order!

Rx: +0.25 -1.75 x 180K’s: 43.00/46.00 @ 090

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EMPIRICAL METHODS



CYLINDER POWER EFFECT

• If the patient has residual astigmatism resulting in blurred vision with spherical OR, a cylinder power effect bitoric is recommended

• This lens must remain stable on the eye as any rotation could blur vision

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CPE EXAMPLE

Refraction/K’s +0.50 - 4.00 x 170; 42/45

DX SPE = 41.50/44.50, Pl/-3.00D

If VA = 20/30, perform Sph-Cyl OR

OR: +1.00 - 1.00 x 170 20/20

Add +1.00 to plano = +1.00D

Add Plano to -3.00 = -3.00D

Design a Bitoric GP Lens

Stop here!

This is all you need to order a lens

Your CLMA member laboratory can provide standardized parameters to complete the data

necessary for the posterior optical zone, peripheral curves, edge shape, center thickness and the anterior control of power and lens mass

OTHER CONSIDERATIONS: TORIC PERIPHERAL CURVES

add 1mm to BCR for secondary curve radii

add 2mm to SCR for peripheral curve radii

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FINAL ORDER

Material: High Dk F-S/A

OAD: 9.4/8.2mm

BCR: 8.13/7.58mm

Powers: +1.00/-3.00D

CT = .19mm

SCR/W: 9.1/8.6 @ .3mm

PCR/W: 11.1/10.6 @ .3mm

POOR CANDIDATE

A difference of 15˚ or more between corneal cylinder axis and spectacle axis (irregular astigmatism)

SUMMARY

There are numerous innovations in GP materials, manufacturing, and surface quality

Use GPLI Toric and Spherical Lens Calculator, Mandell-Moore and/or SPE diagnostic set

GP Bitoric lenses can become your lens of choice in high astigmatic patients

There are many resources available to help you be successful

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GP MULTIFOCALS: WHY THEY ARE A GOOD OPTION IN 2016

RULE OF THREE’S

Number of Fits

Patient Consultation

Pre-Fit

Fitting

Problem-Solving

ASSESS MOTIVATION/GOALS

• What distance(s) is most important to them/goals? Rank Distance, IM, & Near

• Present all options (for their “chronological maturity”)

Advise PT about compromises with CL correction

Is motivation simply not to wear spectacles (cosmesis)

Do they desire their youth back???

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EXPLAIN DYNAMICS OF BIFOCAL GPS

If properly fit, they provide acceptable vision at distance and near

They move up and down during blink cycle (unlike spectacles)

They may experience transient blur with certain directions of gaze

Can the patient accept mild compromise in vision?

ADAPTATION/LENS CHANGES

Lens changes are the rule (1/eye initially, then 1/patient)

6 - 8 weeks to adapt

No Monday morning surprises

BOTTOM LINE

“If you are patient and motivated, there is an 80% success rate with these lenses.”

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PRE-FIT FACTORS

Pupil Size

Tear Film

Lower Lid Position/tightness

DESIGNS IN COMMON USE

Aspheric Multifocal

Concentric/Annular

Translating Segmented

ASPHERIC ADVANCEMENTS

Has evolved into a very popular type due to advancements in technology

New Technology resulting in better polished surfaces, & higher refractive index materials

Addition of higher add power lenses

Lower eccentricity lens designs

Translation???

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ASPHERIC CANDIDATES

Low - medium adds (Don’t R/O High)

Computer use

Athletes

Low lower lid &/or loose lids

Small-avg. pupil size

Critical Vision not essential

BACK SURFACE ASPHERIC MULTIFOCAL FITTING

Most designs fit 1 - 1.5D steeper than K

Must center with limited movement with the blink

Easy to fit via manufacturers’ fitting guide/user friendly

Good design to start with

Topographic Changes with Posterior Aspheric Lens Designs

Pre-Fitting Post-Fitting

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FRONT SURFACE ASPHERIC MULTIFOCAL DESIGNS

Have the benefit of avoiding back surface molding/topography changes

Example: Naturalens Progressive (Advanced Vision Technologies)

GoldenEye AFM (Valley Contax)

Magniclear & Renovations (Art)

Reclaim™HD (Blanchard)

ASPHERIC TROUBLESHOOTING

Inferior Decentration/Excessive Movement: Steeper Base Curve

Insufficient Add Power:

Select Higher Add Lens Design

Use “Modified Bifocal”

TRANSLATING VISION

Prism Ballasted & often Truncated

Crescent/Executive Seg

High Dk Material

Near image moves in front of pupil with downgaze

Typically rests on or near the lower lid

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Reading Position of Translating BifocalBase Curve Selection (courtesy Firestone Optics)

Proper base curve selection helps the lens to translate smoothly upward to position the seg line slightly above the pupil center during down gaze

TRANSLATING VISION: CANDIDATES

Critical vision demands

Any add powers (high add/limited IM)

Lower lid near limbus/good tonicity

Aspheric does not center

• Inferior Apex

FITTING NUGGETS

Diagnostic set(s) Follow manufacturer’s

fitting guide Trial Lens O/R. Translating Pearls:

Position of lower lid to limbus

Seg line to lower pupil position

Evaluate translation in downward gaze

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Lid Position

Optimal Okay ???

TRANSLATING VISION PROBLEM-SOLVING

Excessive Rotation

Lens Positions Too High

No Lens Translation

BLUR AT DISTANCE

Lens too high: Increase prism

Lens too low: Increase OAD

Seg Height is too high

Excessive movement

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BLUR AT NEAR

Seg height too low

No translation

Patient drops head to read, not eyes

Excessive lens rotation

RESOURCES

Your best resource is your laboratory consultant

They can can provide diagnostic fitting sets, online resources for the fitting and troubleshooting of their designs, and well as very good advice based upon extensive experience

If possible, topographies and photos can be beneficial as well

IN SUMMARY

Presbyopes represent the greatest opportunity for contact lens practice growth

For individuals desiring very little to any change in vision at all the distances, the presbyopic contact lens tool box should include GP lenses

toric%20and%20multifocal%20gas%20permeable%20and%20soft ...the contacts you have now are a...

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