Spectacle Lens Update: Everything you need to know

Transcription

7/15/2015
Spectacle Lens Update:
Everything you need to know
Michael C. Vitale, ABOM, LDO, NCLC
Technical Director & Lens Division Liaison
The Vision Council
[email protected]
Michael Vitale has no financial interests to disclose
Impact of Good Vision
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 Average eyewear lifespan...
> 28 months
 Eyewear will be used for...
>
>
>
>
>
over 30,000 miles of driving
viewing 49 or more movies
2.2 weddings / graduations
26 family events & holidays
1 in 3 presbyopes will see a
grandchild for the 1st time
Spectacle Lens Update
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 Areas of Performance
> Design
> Surface
> Filter
> Substrate
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7/15/2015
Single Vision Lens Design
 Historically
> Spherical Lenses
» Corrective Curve Design
- Optical Aberrations
- Magnification for plus power lenses
- Field of view Issues
> Steep curves
» Difficulties fitting in todays flatter frame front designs
Spherical lenses create peripheral distortion
because light is unequally refracted across the
lens surface...
multiple points of focus
.......
 Historically
> Asphericity
» Reduces Optical Aberrations
- Less magnification for plus power lenses
- Less distortion
- Increased field of view
> Cosmetically Flattens
» Allows for flatter, thinner lenses
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Aspheric/Atoric lenses use multiple curvatures to
reduce peripheral defocus and aberration.
single focal point
 What’s New Now!
 As Worn or Compensated Single Vision Lenses
> The Rx is compensated to take into account the following
» Pantoscopic Tilt
» Face form (Wrap Angle)
» Vertex Distance
> Increases field of view
> Less distortion
 Products
Questions?
Comments?
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PAL Lens Design
 PALs Should Provide
> Natural Reading Posture
» greater comfort while reading
> Optimized Zone Placement
» ease of adaptation
> Binocular Width
» wider intermediate vision
> Sharp Distance Vision
» improved contrast at night
> Specialized Design
» task/wearer specific zone distribution
PAL Lens Design
 Natural Reading Posture
Shorter progressions provide more natural
reading postures...
Image courtesy of Essilor of America
...a natural reading posture relies primarily
on head movements
PAL Lens Design
 Optimized Zone Placement
Distance Rx and ADD power determine
optimal zone placement...
HYPEROPE
MYOPE
...true multi-design PALs optimize zones
for ametrops, for easier adaptation
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7/15/2015
PAL Lens Design
 Binocular Width
The ability to maintain fusion is called
"binocularity"
...binocularity determines width- not the
spherical area of the channel
PAL Lens Design
 Binocular Width
Patented Design Technology allows
specific alignment of astigmatism...
...this increases binocularity- and therefore
intermediate width
PAL Lens Design
 Sharper Distance Vision
New Design Technology controls
aberrations in the distance zone
...control of aberrations provides clinically
proven gains in contrast
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PAL Lens Design
 Specialized Design
Progressions can be designed specifically
to a task
FAR DISTRIBUTION
STANDARD DISTRIBUTION
NEAR DISTRIBUTION
PAL Lens Design
to a frame type
SHORT DISTRIBUTION
PAL Lens Design
to an Rx
OPTIMIZED ZONES
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7/15/2015
PAL Lens Design
to a patient characteristic
EYE MOVER
HEAD MOVER
Fitting & Dispensing
 Products
> Traditional & Freeform
» Thanks to the Lab Division of TVC
> Freeform
» Thanks to Vision Care Product News
“Computer Glasses”?
 “Task Specific”
> Helps the eye adjust to intermediate-distance objects
such as computer screens
» A modified lens power provides the consumer with a large
field of view
» Too many products to mention, reference the Progressive
Lens Identifier
> Powerboost “single vision” lenses for non-presbyopes
» Zeiss, Hoya, Essilor, etc.
> Over the counter products such as GUNNAR
> Custom designed
» Double FT/Rd seg
» Inverted
» Golf seg
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Fitting & Dispensing
 Proper fitting is crucial to the
performance of ANY and ALL
designs
> Proper adjustment of the frame
» Faceform
» Pantoscopic Tilt
» Vertex Distance
> Proper placement of the optics
» Monocular PD’s
» Monocular Fitting Heights
An improper fit will compromise the performance of ANY design
Fitting increases in importance with design complexity
Questions?
Comments?
Lens Surfaces
 High Performance Surfaces Provide
> Hardcoating – Thermal and UV
» greater durability
> Multi-layer Anti-Reflective Stack
» sharper vision
» increased night vision
» better cosmetics
> Hydrophobic & Conductive Layers
» easier to clean
» greater durability
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Lens Surfaces
 Thermally-cured Hardcoat
The lifespan of a lens is determined by the
durability of the surface
SUBSTRATE
Primer
Silica-Resin
Hardcoat
...surfaces are thermally bonded into the
substrate
Lens Surfaces
 Multi-Layer AR Stack
Surfaces include a multi-layer AR for
increased transmission
SUBSTRATE
Multi-Layer AR
...AR also reduces night-time reflections/glare
and provides superior cosmetics
Lens Surfaces
 Hydrophobic & Conductive Layers
An AR incorporating a TCO (transparent conductive
oxide) will repel dust and other particles
SUBSTRATE
Hydrophobic Layer
...a hydrophobic layer repels water & oilresulting easier and less frequent cleaning
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Lens Surfaces
 Hydrophobic & Conductive Layers
Hydrophobic durability is a function of
coating density...
...higher densities lead to a longer effective
hydrophobic lifespan
Lens Surfaces
 Include high-performance surfaces on
your lenses
> Nearly all patients want:
» Increased visual acuity
» better night vision
» increased durability
» ease of cleaning
» less noticeable eyewear
 60% of all US eyewear consumers choose
AR when informed of its benefits
Questions?
Comments?
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7/15/2015
Lens Filters
 Lens Filters
> UV Filters
> Photochromic’s
» adjustable filtering
» UV protection
> Polarized
» glare reduction
» superior contrast
» sport & vocational applications
» UV protection
> Fixed Tint
» neutral & selective filters
> Specialized Filters/AR Coatings
» Selectively filters blue light and UV
Lens Filters
 Ultraviolet Filters
ozone
> There are 3 types of UV
» UVC < 285nm
» UVB 286 – 320nm
» UVA 320 – 380nm
» HEV > 380nm
 Only 2 materials do not block UV
» clear CR-39
» clear glass
Lens Filters
 Ultraviolet Filters
> On average, 80% of UV exposure will occur
prior to age 20
 100% UV protection is a standard-of-care
requirement for all children
> Polycarbonate or Trivex
> brimmed hats
> sunscreen
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Lens Filters
 Photochromic lenses provide
> Comfortable vision in nearly all lighting conditions
> Complete protection from UV
Image courtesy of Transitions
Lens Filters
 Polarized Filters provide
> reduction of glare
» reflections from flat surfaces are reduced or
eliminated
> increased contrast sensitivity
» selective filtering of glare
> sport & vocational applications
» watersports
» driving
Lens Filters
 Reduction of glare
Non-polarized light contains energy along
all axes along its direction
...a polarizing filter polarizes light along a single axis
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Lens Filters
 Reduction of glare
When light hits a smooth transparent
surface, polarization occurs
...water causes horizontal polarization
Lens Filters
 Increased contrast sensitivity
Non-polarizing filters attenuate light nonselectively, reducing contrast
Lens Filters
 Increased contrast sensitivity
Polarizing filters preserve contrast by
selectively filtering glare
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Lens Filters
 Polarized applications - driving
Polarized lenses increase contrast perception
& decrease reaction times
Lens Filters
 Polarized applications - driving
Polarized lenses increase contrast perception
& decreases reaction times
20/10
20/15
20/20
1.0
20/25
10.0
100.0
Snellen VA
20/32
20/40
20/50
Tinted AR
20/63
Polarized AR
20/80
20/100
Contrast
 Neutral & Selective Filters
Neutral (grey) filters attenuate light evenly
across the spectrum- selective filters may
improve contrast
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Lens Filters
Objective of Filters
Filter out harmful / distracting light
• UV and/or IR
• reflected glare
Transmit useful light
• preserve contrast
• manipulate color perception
– preserve color perception (neutral grey)
– alter color perception (all other colors)
Lens Filters
ALL filters (except UV and AR)
reduce light transmission
(including "contrast enhancing" night
driving lenses)
Lens Filters
Specialty Filters / AR Coatings
Filter HEV “Blue” Light
UV and/or Blue Light
Reflected glare
Transmits 97.5% light
Reduces eye fatigue when using computers,
iPads/Tablets and mobile devices
ZEISS DuraVision BlueProtect
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Questions?
Comments?
Substrates (Lens Materials)
 Premium Substrates Provide
> Safety
» Impact Resistance
» UV Protection
> Structural Durability
» High Tensile Strength (drill mounts)
> Superior Cosmetics
» Thin Profile
» Optical Clarity
> Superior Comfort
» Light Weight
 Safety
> Polycarbonate is the only material that retains a constant
level of impact resistance in all forms
> Polycarbonate resists extreme impact level with any surface
UNCOATED
HC SURFACE AR SURFACE
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 Safety
> All materials MUST pass the FDA drop-ball test
» (Federal Law)
> Hard coating and AR coating will greatly reduce impact
resistance
UNCOATED
HC SURFACE AR SURFACE
 Structural Durability
> Tensile strength is a measure of a materials ability to resist
“tearing”
» This equates into resistance to splitting in drill mounts
 Tensile Strength By Material
» 80.5 kg/f = 1.60 (MR8)
» 70 kg/f = 1.67 (MR10)-Approx.
» 67.3 kg/f = 1.67 (MR7)
» 61.2 kg/f = Trivex
» 52.9 kg/f = 1.70
» 44.9 kg/f = polycarbonate
» 15.6 kg/f = CR-39
80kg
 Superior Cosmetics
> High Index Lenses Reduce Thickness
1.50
1.60
1.74
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7/15/2015
 Superior Cosmetics
> Optical Clarity Is A Function Of
» Transmittance
- Perception of white target
» Color Rendering
- Perception of chromatic target
» Contrast
- Ability to perceive contrast near and far
> Abbe is not a major function of clarity
» The eye has approximately 1.00D of linear chromatic
aberration (which does not impair vision)
- (-10.00D poly lens viewed at 30° produces <0.50D of linear
chromatic aberration)
Dispensing
 Recommending Substrates
> Polycarbonate for Safety
» Children (Trivex is also a good option)
» Monocular patients
» Most safety applications
> Tensile strength for drill mounts
» 1.60, 1.67
» Trivex
» Polycarbonate
> Higher Index for Thinness
» 1.60, 1.67, 1.70, 1.74
> Low Specific Gravity for Lightness
» Polycarbonate
» Trivex
Dispensing
 Summary
> Design
» Binocularity = Width
» Reduced aberration = Contrast sensitivity
» Customization = Potential for greater performance
> Coatings
» Thermal cure = permanent adhesion
» AR Coating = Better Vision and Greatly Improved Cosmetics
- Conductive Layer = anti-static
- Dissymmetric = hydrophobic
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Dispensing
 Summary
> Filters
» UV
» Photochromic's
» Polarized
» Fixed Tints
> Substrates
» Polycarbonate for Safety (Trivex)
» High Index
- Great for Drill Mounts
Questions?
Comments?
Special thanks to
Michael C. Vitale, ABOM, LDO, NCLC
Technical Director & Lens Division Liaison
The Vision Council
[email protected]
Special Thanks to
Pete Hanlin, Technical Director
Essilor of America, Inc.
19

Spectacle Lens Update: Everything you need to know

Transcription

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