Optical dispensing.pptx

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Optical Dispensing

Over view
• Definition
• Frame style & Cosmetic Dispensing
• Frame measurement
• Spectacles Instrument Accessories
• Counselling
• Ophthalmic lens fitting
Optical Dispensing 2
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Definition
• An optical dispensing is subspecialty of
optometry of which includes all
procedures from the time the glass
prescription is presented to the optician
till the patients are on with the pair the
glasses satisfactorily.
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• Frame selection is often a process of trial and error
can be time consuming.
• Proper assistance in frame selection is especially
important for the type of patient who may be inclined
to accept the first frame presented.
• The best frame for a patient complements his or her
facial structure, requires minimal adjustments, and
will securely hold the lenses in place.
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Frame style and cosmetic dispensing

Frame selection
• Follow these steps to choose a best stylish eyeglass
frames.
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Optical Dispensing
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Determining facial wrap
• Broadly, there are six face shapes that we
observe around the world.
 Oval
 Round
 Square
 Rectangle
 Triangular
 Heart
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Optical Dispensing
22.01.2016

Frame for Oval Face shape
• Ovel face shape is the most common face
shape and is considered as an ideal one.
• We recommend oversized or rectangular
frames
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Frame for Round Face shape
• Round faces are usually proportional to width
and length that features your full cheeks and a
broad forehead.
• We recommended rectangular or angular frames
for round face shaped persons.
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Frame for square Face shape
• Square faces are characterized by a broad
squares forehead and a strong jaw line.
• We recommended Round or Oval shaped
frame.
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Frame for Rectangle face shape
• Rectangle faces are regarded as the elongated
proportion that means a longer, narrower face
and nose, along with the
same strong jaw line and
squares forehead.
• We recommended round
or cat eye shaped frame.
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Frame for Triangle face shape
• Triangle face have a narrow forehead, but
wider cheek.
• These faces look the best in top heavy styles
which help balance out the jaw.
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Frame for Heart face shape
• Heart shaped faces have a broad forehead and
narrow jaw line or small chin.
• We recommended deep vertical frame shaped
frame.
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Frame Measurements
• Datum system
• Boxing system
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Datum system
• Previously used system for measuring lenses
was established as a system of reference points
for the frames & lenses so that position of lens
optical centres & bifocal
segment heights would
be consistent.
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Boxing System
• In 1962 the optical manufacturers association
adopted the boxing system to provide a standard
for frame and lens measurement that greatly
improved upon the accuracy of previous systems.
• The boxing system is based upon the idea of
drawing an imaginary box around a lens shape
with the box’s sides tangent to the outer most
edges of the shape.
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Frame measurement guide
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• It is measured as the horizontal distance
between the furthest temporal and nasal edges
lens shape of the box.
• This is measured in millimeters.
“A” MESURMENT
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• It is measured as the vertical distance between
the furthest top and bottom edges lens shape
of the box.
“B” MESURMENT
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• Frame difference
• Datum Line
• Geometric center
• Distance between lenses
• Distance between Centers
• Effective Diameter
• Segment Height
• Segment drop
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Optical Dispensing

Pre dispensing measurement
• Facial wrap
• Pantascopic tilt
• Vertex distance
• IPD measurement
 PD rular
 Pupillometer
 Pen torch
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• Facial wrap
facial wrap the frame fills properly following
the curved line of the face.
• Pantascopic tilt
Pantascopic tilt is the angle between the normal
to the temple and frame front.
• Vertex distance
Vertex distance is the distance between the front
of the cornia and back of the lens.
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Spectacles Instrument accessories
PD measurement devices
• PD ruler
• Pupillometer
• Pen torch & marker
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PD Ruler Method
• Sit directly opposite the patient (arm’s length)
• Position yourself 40cm in front of the patient.
• Eyes are level.
• Place ruler on the bridge of the patient’s nose
• Hold pen torch under your left eye directed
at the patient’s RE
Optical Dispensing
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• The dispenser aligns the zero mark of the
demo lens with the centre of patient’s pupil.
• The PD for distance is read as the mark falling
on the left pupil.
22.01.2016 Optical Dispensing 26

The Pupilometer method
• Fast and accurate measurement
for monocular and binocular
PDs.
• The variation between
the visual axes and
pupil center.
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Monocular PD
Binocular PD
Practitioner’s side
Patient’s side

 Procedure:
Hold the instrument in both hands and rest the pupilometer
on patients face.
Ability to vary working distance from 20cm to infinity
Internal hairline moved until line and corneal reflection are
coincident
Corneal reflection typically located nasal to pupil center (2
to 5 )
Pupilometer
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Subject’s view
Practitioner’s
view

Direct pupillary reflex marking
• A pen torch will produce clear corneal
reflections.
• Position yourself 40cm in front of the patient.
• Eyes are level
• Hold a pen light under your left eye, aiming
the light at the patient’s eye.
• Mark the patient corneal reflex in marker.

• Mark the patient corneal reflex in marker.

Layout card measurement
• Measure monocular PD. The recommended
procedure is the use of a pupillometer.
• Incorrect PD may cause difficulty in using
different zones through the lens.

Counselling
• Lens materials
Glass
Plastic
Hi-index etc
• Lens Design
Single vision
Bifocal
Executive
Progressive etc
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• Lens coating
ARC
SRC
UV OR Polarized
• Photochromatic
• Tinted lens

Lens material
Traditionally, people used to prefer glass lenses. But
they have become less popular now due to the
danger of breaking. They are also heavier in weight
than alternatives. These days, CR-39 plastic lenses
are the preferred material for spectacle lenses.
It is safer, cost effective and offers an outstanding
optical quality. some people would be satisfied
with just that-a cheap good quality lens which can
correct vision.
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• People become more aware, they’ve started
realizing there is more to it than it appears.
Like UV protection, even lighter weight,
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Lens Coating
• Every good lens has 3-4 coatings,
• Each of a microscopic thickness.
• Most common of coatings is for toughening the
lenses to make it break-resistant.
• Then UV protection coating and Scratch resistant.
• Lastly, there is the anti-reflective coating
Primarily helps in reducing the
effect of reflective light from
bright objects such lamps or
car headlights at night.
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UV Protection and Polarized lens
This is one of the major deciding factors. UV
exposure has been clinically proven to be an
important cause of cataract because of its
oxidative effects on humans.
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Photochromatic
• A major breakthrough in the area of absorptive
lenses took place in 1964 with the invention of
corning’s photo gray photo chromatic.
• These lenses darken when exposed to light.
• photochromatics are available in both glass
and plastic material.

Tinted lenses
• A tint is usually associated with a certain
quantity and depth of color, the depth of color
is described as density of lens.
• Both glass and plastic lenses can be tinted to
achieve the desired color.

Ophthalmic Lens fitting
Laying off
• Before a lens is edged it must be marked so
that cylinder axis if any is set according to
prescription and its optical centre is in correct
position relative to lens shape.
• We use a lenso meter to mark three dots
indicating optical centre position and the
horizontal meridian.
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• These horizontally placed dots are used to set
the lens on correct axis.
• In case of bifocals and trifocal and trifocals the
three dots should be parallel to top of the
segment.
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Lens cutting
• Once the lens is layed off it must now be cut
into desired shape.

Edging formers
• Shanking tongs were then used
to crumble the edge away until
it roughly resembles eye shape.
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Lens Edging formers
• Flat edge
• Bevel edge
• Mini bevel edge
• Grooved edge
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Flat Edge
• This is the simple form of edge.
• It is mainly used for lenses fitted
to rimless mounts or as an
intermediate stage in the
production of other edge forms.
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Bevel Edge
• The bevel edge is used for
lenses to be fitted in shall
and full rimmed frames.
• To avoid pressure on the
peak of bevel and the attendant risk of
chipping the lens.
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Mini Bevel
• The peak of a normal bevel lies approximately
midway between the two surfaces with strong
minus lenses and high cylindrical power.
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Grooved Edge
• It is simply a flat edge with central groove.
• Used mainly on lenses fitted to spectacles of
the nylon supras or semi rimless types.
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Hand Edgers
• A hand edger is still indispensable piece os
equipment although new automatic are being
preferred. For starting ensure that the hand edging
machine in good working condition. It should be set
up with adequate water. Hold the lens is both hands
with convex side up. Rest your hands on the dip tray
and press the lens against the revolving diamond
wheel. Make sure to hold the lens across the wheel
and at a slight upward angle. Now slowly rotate the
lens passing the grip of lens from hand to hand.
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• After edging match size of edged lens with the
frame. The lens is right when the shape is
exactly like that of the frame to be fitted.
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22.01.2016

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