Post on 14-Dec-2015
FreeForm® Progressives
Welcome
• What is free-form?
• Digital FreeForm lenses vs. conventional lenses
• General information about the technology
• Not hard tools needed anymore• How precise the technology can be• What can be done by advanced
ophthalmic design and FF technology?
• Free-form can produce any ophthalmic lens type
General information about the technology
• Free form is a manufacturing technology that allows cutting and polishing arbitrary surfaces
• A lens is free-form if– At least one of its surfaces is made with free
form technology and– That surface is not spherical neither torical*
*Free form machines may cut standard surfaces, but as they can also be cut with standard methods, the corresponding lenses should not be named free-form lenses.
FreeForm surfacing
• Blocking• Generating • Polishing• De-blocking
Flexible toolDiamond cutter/sintered diamond milling tool
Not hard tools needed anymore
How precise the technology can be
• What is claimed: 0.01 D• Very difficult to achieve
in plastic• Well tuned process with
tools, soft pads and slurries not worn out, guarantees better precision than standard milling and polishing methods.
What can be done by advanced ophthalmic design and FF technology?
• Optimize the lens for the power that the user perceives, not the power measured in the focimeter (which is ok for quality control, but is not the power perceived by the user)
• Optimize the lens for any position of use (tilts, distance to the eye, etc…)
• Optimize the lens for any base curve (the spherical base curves used with FF lenses)
• Optimize the lens for each prescription• Optimize the lens for particular applications• Better control of lens thickness• Off-centering without losing optical quality…..
…Important improvement to the optical quality of standard lenses
Free-form can produce any ophthalmic lens type
Formation of distortion in progressive lenses<Conventional PAL>
Formation of distortion in progressive lenses<Backside PAL>
Distortion in Progressive Lenses
Wider visual field in Backside PAL
Free Form progressive offers %30 wider visual field compared to conventional progressive thanks to the progressive surface on the backside of the lenses.
Comparision between FreeForm and Conventional PAL
Conventional
Based on the geometry of the lens to calculate the power resulted
Enhanced view mainly in the central gaze direction
Small degree of lateral unwanted astigmatism reduction
No personalization option
FreeForm
Based on advanced binocular eye-lens system modelEnhanced view whatever the gaze directionHigh degree of lateral unwanted astigmatism reductionPersonalized lenses
Conventional vs. FreeForm
• Smaller Optical visual zones• More lateral astigmatism• Higher astigmatism maxims
Bigger optimal visual zones Less astigmatism Lower astigmatism maxims
Advanced Ophthalmic digital power structureEach lens is individually calculated using advanced algorithms to
guaranty an optimized power structure
Automatic variable inset
Inset (d) calculation method:
Paramteters to be considered for inset calculation:
s Near working distance
l’2 Distance from lens to eye center
NPD Naso-pupilar distance
P Prescription
Conventional vs. FreeForm Inset Calculation
Inset not taken into account in conventional lenses
Correct inset calculation in FreeForm
Optimized reduction of lateral unwanted astigmatism
• Due to the advanced eye lens system optimization the lens minimizes the lateral unwanted astigmatim.
Optimized reduction of lateral unwanted astigmatism in FreeForm
Lateral unwanted astigmatism have been reduced also for the human eye
Enhanced vision whatever the gaze direction
Conventional lens SV FreeForm individual SV
High vision performance in FreeForm
With FreeForm
Conventional
Wider and clearer far also for oblique gaze directions
Wider and clearer near
Conventional PAL FreeForm PAL
1. Wider and clearer far2. Wider and clearer near3. Optimized intermediate4. Minimized lateral astigmatism
High vision performance in FreeForm
Personalization• Personalization according to morphological parameters:
• Panto
• Wrap (ZTILT)
• Back Vertex Distance (BVD)
• Near Working Distance
• Pupillary Distances
• Frame Trace
Personalization
Average personalization:
• FreeForm uses average values for optimizing the final lens to make easily the lens ordering
Real data personalization:• Additionally to average data, FreeForm optimizes the lens using the real values of each wearer for:
– IPD – Inter-pupil distance– SEGHT– HBOX– VBOX
Parameter Label Average value
P.D. IPD 32 mmVertex BVD 14 mmPantoscopic PANTO 12ºWrap ZTILT 5 º
FreeForm Individual Power Optimized for the wearer
SPH: 3.25CYL:1.50AX:75ADD:2.00
BrandTraditional progressive
User power
SPH: 3.25CYL:1.50AX:75ADD:2.00
FreeFormİndividual progressive
Base: 6.25 Index: 1.67 Base: 6.25 Index: 1.67
Lens meter powerDistanceSPH: 3.19CYL:1.43AX:62
Near:SPH:5.10CYL: 1.67AX: 58
Prescribed power = Measured power.The final user will perceive differences due to the use position.
The final user will perceive the prescribed power.
Expected power in the lens meter.
Many thanks for your attention !