Vertical progressive component (image
magnification in verticaldirection)
horizontal and vertical progressive components.
While many attempts have been made in the past to
eliminate the unstable feeling experienced by presbyopes, the results have been
minimal. The time was right to take an entirely different approach in order to
counteract these negative effects, combining existing know-how with the very
latest software calculation programmes and production facilities. Before this
could be done, the progressive design would require further analysis.
Progressive component and normal distortion, measured along the vertical planes.
Along the so-called ombilic line, a cross-section
through the surface is circular and the radius of the circles in the vertical
plane continuously decreases from radius far distance to radius near. Because
addition power only increases in the vertical direction, an image enlargement
will appear in the vertical direction. Our visual system can easily adapt to
this so called Normal Distortion.
Vertical progressive component (Position Front surface,
far from the eye)
Horizontal progressive component and skew distortion, measured along the
Measured along the horizontal planes,
distortion/magnification negatively affects our visual performance because the
far and near distance surfaces with tangential and sagittal radii curvature
must be blended together in a continuously changing progression.
The results of the horizontal progressive components will lead to unacceptable
deformation for presbyopes when the peripheral deformation is not correctly
This so-called skew distortion is uncomfortable for the wearer because it gives
a swinging effect and insecure feeling when moving.
Horizontal progressive component (Position back
Step 1: Individually defining the most effective
position of the progressive components in relation to the eyes and calculating
a unique front and back surface.
Step 2: Restructuring the separated design properties
by a new virtual evaluation and calculation technique.
Step 3: Re-integration to complete the integrated total
Expressing the right position of vertical progressive component.
What if the vertical progressive components were
located on the back surface? More eyeball rotation will then be needed, because
of the enlarged vertical visual field red lines/arrows) and enlarged
interaction distance from far to near and vice versa. A longer vertical visual
distance is needed to reach full addition value/compensation of the
accommodation shortage. Positioning on the back surface will therefore have a
negative influence on the effectiveness in a vertical direction.
Conclusion: Vertical progressive components should be
located on the front surface.
Result: the shortest and most effective progression in
the vertical direction, short and effective eyeball rotation, fastest
compensation for accommodation shortage and fastest interaction between far and
Horizontal progressive component
(Position close to the eye)
Expressing the right position of horizontal progressive component and the
influence of skew distortion.
The closer distortion is to the eye, the less image
deformation influences the peripheral visual perception/performance. This was
one of the reasons to position the horizontal progressive components on the
back surface - it widens the clear undistorted visual field in a horizontal
direction. As a result, the usable distortion-free corrective surface is
enlarged, opening up new possibilities for a wider clear visual field at all
distances, regardless of the prescription.
Vision - perception - experience.
Integrating both surfaces in the most efficient
position is one thing. But the
goal when designing Hoyalux iD was to make a decisive
step forward in reducing instability, providing multifocal wearers with an
instantly recognisable feeling of security and natural vision.
Hoyalux iD took up the challenge by integrating the
best of both worlds: Splitting Function (vertical progressive components/normal
distortion) and Comfort (horizontal progressive components/skew distortion).
Next, both the vertical and horizontal progressive components were
recalculated. This resulted in an optimisation of both the functional part
(effective interaction) and the comfort part (improved wide clear visual
field). A short effective corridor length and the widest, distortion-free
visual surface for all distances were created. Hoya calls this the Integrated
Double Surface Progressive Lens.
Integrated design: Vertical progressive component at
front surface and the horizontal progressive component in back surface.
The next challenge was to balance the new surface
structure. Skew distortion would still influence the experience of wearing a
progressive design if the newly structured front and back surfaces were
Evaluation techniques evaluating the quality of the progressive design.
Swaying and distortional complaints usually occur when
wearing progressive designs, especially when moving. This effect can continue
for years. The 'standard' progressive lens designs were the result of
evaluation and calculation techniques that were available in the early days.
While these techniques had also been dramatically improved over the years, the
optimisation process had reached its natural limits.
Taking a totally different approach, based on 3D
virtual evaluation and calculation techniques, we are now capable of
calculating and quantifying the experience of progressive wearers by monitoring
and evaluating the insecure feeling caused by peripheral deformation.
Especially while moving, walking down steps and looking in oblique directions,
this phenomenon can lead to non - adaptation and dissatisfaction. Before
explaining the real revolution in Hoyalux iD's design technique, let us first
clarify the improvement in design evaluation technology.
That is why Hoya has
Deformation index mapping and 'Balanced View Control'.
Skew Deformation Index mapping is a new technology for
evaluating progressive lenses. 'Balanced View Control' is also calculated by
virtual computer simulation to show us how large a distortion results from
looking through progressive lenses at various angles.
The following illustrations show Point Deformation and Skew Deformation
Point Deformation mapping includes a Normal Deformation and a Skew Deformation
component. To achieve maximum information about deformation performance, it is
best to consider these constituent parts separately. Skew deformation analysis
is required to evaluate and quantify the distortion of vision suffered by
wearers of progressive lenses, who are very sensitive to the resulting swinging
Point Deformation Index mapping is calculated by
virtual computer simulation to quantify the extent of deformation in each point
of the visual field when wearing progressive lenses.
Deformation index mapping existing generation progressive design.
Unstructured more deformation over the entire surface.
deformation index mapping Hoya-lux ID. Perfectly balanced distribution over
the entire surface.
Point Deformation mapping includes:
Normal deformation component (vertical and horizontal
component of Point deformation index)
Horizontal direction( horizontal enlargement)
vertical direction (vertical enlargement)
Skew deformation component:(oblique component of
Point deformation index)
Each coloured area refers to the level of
deformation. The value of Point and Skew deformation index is divided in several
groups, as 0.00 to 0.025, 00.25 to 0.050 Etc... (calculated power difference
between horizontal (a) axes and vertical (b) axes of the spectacle magnification
ellipse calculated by virtual calculation)
Skew Deformation Index mapping separately
will detect more information about Vision, Perception and Experience,
especially evaluating the experience of unbalanced perceived images when the
wearer of progressives shifts of eye orientations while moving.
Skew deformation index mapping
existing generation progressive design. Unstructured and more oblique
deformation over the entire surface.
deformation Index mapping Hoyalux ID. Balanced distribution over the entire
The new concept of spectacle magnification and
Point deformation indices (Point Deformation Index and Skew Deformation Index)
makes it possible to examine the distortion of a spectacle lens, especially
Hoyalux iD, precisely and quantitatively. This will undoubtedly help further
improve optical design in the future.
Another, even more revolutionary, evaluation technique
is the quantification of the experience of movement of an object or scene
across the retina caused by a progressive design (the wearer perceives that the
floor is pent or deformed, feels uneasy when descending stairs or feels like he
is on a boat).
The way we see, interpret and experience
images is being simulated and ntegrated in the virtual calculation program. This
data are the basic input for stable natural vision with Hoyalux iD.
Hoya calls this evaluation principle
'Balanced View Control', and it functions as follows. Computer simulation
creates an original target image composed of a large number of small circles.
The perception of this image travels along virtual lines of vision to traverse
the progressive lens at a given point and then enter the ocular system. The
following step is the calculation of a large number of retinal snapshots
corresponding to the small target circles composing the target image.
Deformation virtual image perception
image perception after re-calculation
Existing generation design
After passing the progressive lens, what was circular
becomes elliptic (ellipses are perceived on the retina of the model eye),
indicating the deformation.
A spectacle magnification ellipse is formed for each point in the target image,
describing how the image in the neighbourhood of that point is distorted when
viewed through our test lens. The deformation caused by the lens is therefore
defined by the spectacle magnification ellipses throughout the visual field.
It is necessary to quantify the extent of deformation for each point in the
Deformation Index Calculation.
Skew deformation recalculation can help
improve visual performance as well as reduce vision distortion and the swinging
effect. A concept of "Skew Deformation Index calculation" has been developed
to evaluate the unpleasant feeling caused by oblique deformation, where the
degree of distortion caused by the lens is the basis for calculating the ratio
of major axis "a" and minor axis "b" of the spectacle magnification ellipse. By
recalculating the deformed peripheral progressive components, we are able to
reduce skew deformation and achieve a much more comfortable feeling for the
Integrated Design ensures that a progressive
performance in terms of function and comfort is evenly distributed
across the front and back surfaces. By keeping normal distortion on the front
surface, vertical eye and head movements are kept to a
minimum. Concentrating skew distortion on the back surface suits the eye
better and results in extra wide scope across the entire far, intermediate and
near vision area.
As skew distortion is more uncomfortable for the
wearer than normal distortion, it is crucial to normalise swaying and vision
deformation effects. Integrating the new 'Balanced View Control' virtual
evaluation technique, using computer simulation to analyse distortion due to
looking through lenses at an angle, and integrating the 'Skew Deformation
Index Calculation' technique all contribute to assurance and steadiness while
wearing Hoyalux iD progressive designs.
interaction between far and near vision
||No swinging effects while
at all distances
iD: the world's first Integrated Double Surface Progressive Lens with 'Balanced
Balanced and more comfortable peripheral
Ergonomic dispersal of deformation over the entire
Wide intermediate corridor
More unlimited distortion-free areas
Perfect interaction between far and near vision
No swinging effects
To know more: Hoyalux