Lensa progresif

PROGRESSIVE LENS
Refraction, Contact Lens and Low Vision Sub Division
Department of Ophthalmology
Medical Faculty of Andalas University/ DR. M. Djamil Hospital
Padang
2019
MEIRONI WAIMIR
Literatur Review
dokter.ronnie@gmail.com

INTRODUCTION
Progressive Addition Lens /PAL
A corrective lens used in eyeglasses to correct
presbyopia and other disorders of accommodation
 Characterized by a gradient of increasing the lens power
 added to the glasses.
 Power gradually increasing from the distance zone, through a
progressive zone to the near zone.

INTRODUCTION
1907
first
patented by
Owen Aves
1922
Duke Elder
developed the
world's first
commercially
PAL
1953
Bernard
Maitenaz,
patented Varilux
and introduced
in 1959 by
Essilor
1972
Maitenaz created a
truly aspherical
design and
manufacturing
process (Varilux 2)
1983
Carl Zeiss AG
developed free-form
technology and has
been patented

 Progressive lens  a type of multifocal lens that has a
surface with a continuous smooth increase in addition (plus)
power.
 Gradual increase in power  intermediate zone
DESIGN AND CHARACTERISTICS OF
PROGRESSIVE LENS

Gradual increase in
curvature
PROGRESSIVE LENS
Produces a corridor
that progressively
increasing plus power
Variable focus
intermediate zone
All three zones are enclosed on both sides by blending regions and
geometric distortions

• Bifocal Lens
Has two fixed focus vision zones, separated by visible
discontinuity  image jump
Intermediate vision is often limited
PROGRESSIVE LENS
• Progressive Lens
Provide the desired add power without any breaks, ledges or
lines by blending the transition between the distance and near
zones.
The transition  very smooth enough to prevent sudden
changes in image jump.

EARLY PROGRESSIVE LENS DESIGN
• Owen Aves (1907)  dual surface progressive lens design
section of a cone on one side and elliptic cylinder on the other.
• The progressive region of the surface can be represented by
circular cross section that gradually decrease in diameter,
thereby increasing in curvature  Elephant’s trunk.

Progressive Lens Structure

CHARACTERIZING PROGRESSIVE LENS
• In the blending region there is a contour plot that shows the optical
quantity levels of the lens.
• Progressive lenses have an astigmat plot like finger print  useful
for evaluating the strength distribution of additions.

The rate of change in cylinder power away from the progressive
corridor increases as the Add power of the lens increases
CHARACTERIZING PROGRESSIVE LENS
The rate of change in cylinder power away from the progressive
corridor increases as the length of the progressive corridor
decreases
Minkwitz’s Theorem

DISTRIBUTION OF SURFACE OPTICS
Wide distance and reading zones
Narrow intermediate zones
Close spacing of contour lines
Reduced distance and reading zones
Wider intermediate zone
Wide spacing of contour lines

ADVANTAGES OF PROGRESSIVE LENS
• Progressive lenses provide the correction that presbyopia
patients need to see clearly at all viewing distances.

• Comfortable intermediate vision
Using the distance vision
portion of a bifocal
Using the intermediate
portion of aprogressive
Using the near vision
segment of a bifocal

• Progressive lens avoid discontinuities (image jumps) that are
found with bifocal and trifocal lenses.
• More cosmetically attractive  no line of damarcation
In PAL, an uninterrupted curves links distance vision, intermediate
vision, and near vision with no visible separation

DISADVANTAGES OF PROGRESSIVE LENS
Disadvantages PAL
Peripheral
Distortion
Fitting
Cost

The Best Candidates for PAL are :
• Patients with early presbyopia who have not previously worn
bifocal lenses.
• Patients who do not require wide near-vision fields.
• Highly motivated patients.
Patients who change from conventional multifocal lenses to PAL
should be advised that distortion will be present and adaptation will
be necessary.

PROGRESSIVE LENS FITTING
• Lens manufacturers now offer PAL  more compact, smaller,
more fashionable frames and still get the full effect from the
lens.
• The main difference between lenses is the width of the central
corridor.
• Wider intermediate area  the patient who works on the
computer.
• Wider reading area  the patient who spends a significant
amount of time reading.

Additional information that will assist in selecting progressive lens
that will provide the best possible vision, including:
 Patient’s prescription
 Patient's occupation
 Leisure time activities
All information collected will help in choosing the right design.

Step 1. Frame Selection
• Frames accomodate the lenses, fit comfortably, suit the patient’s face
shape, and be stylist.
• Check the frame before taking any measurements.
• Vertex distance (12-14 mm), face form, and pantoscopic tilt 8-12
degrees.

Step 2. Frame Measurements
• Place properly adjusted frame on patient
• Mark each lens at the pupil center with a
felt-tip marker.
• Draw a horizontal line on each lens
• Check to see that the lines are at the center
of each pupil.
• Measure fitting height from the deepest
point of the lenses to the pupil center.

• Take monocular PD measurements.
• Use a corneal reflex pupillometer to ensure exact measurement
of center pupil.
• Take PD measurement for infinity and near and record the
measurement
Step 3. Pupillary Distance (PD) Measurement

• Use the card provided by the progressive manufacture to check
lenses.
• Use the patient’s fitting height and distance PD measurements.
• Place lens cross over the layout chart to verify the lens will fit in
the frame.
• If it does not fit, select another frame.
Step 4. Check Lens Cut Out

Patient Education - Adaptation
• Always wear progressive glasses during activities.
• To see an object on the side, turn your head, don't glance
because it will cause visual distortion.
• Do not look at the edges of the lens because these are
distortion areas on the progressive lens.
• If you cannot adapt yet, it is not recommended to ride
using progressive glasses.
• Move the eyes when looking at objects or text above and
below.

CONCLUSION
Progressive lenses are eyeglass lenses that ideal for presbyopia
because providing a continuous increase in the plus power focus
to compensate lack of accommodation. The progressive lens
allows clear vision for distance, intermediate and near zone
where dioptric power gradually increases along the lens surface
from the top to the bottom.

Progressive lens provides comfortable intermediate vision,
avoid image jumps, and more cosmetically attractive. The
disadvantages of progressive lens are there is peripheral
distortion, requires fitting, and more expensive than other
multifocal lenses.
Progressive lens fittings is important to get the best vision and
patient comfort in using progressive lens glasses.
CONCLUSION

Thank You

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