Post on 24-Jan-2017
Churawan Lal Sahu M Optom 1
Scientific Measurement ProtocolsChurawan Lal sahu
M Optom
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Measurements
Single vision
Bifocals
Progressive lenses
Scientific Measurement Protocols
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Single Vision
IPD
Centration
Scientific Measurement Protocols
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Scientific Measurement Protocols
Effect of decentration
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Bifocals IPD
Distance & Near
Segment insertion
Segment height
Scientific Measurement Protocols
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Scientific Measurement Protocols
Near PD & Segment insertion
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Segment height
Scientific Measurement Protocols
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Progressive lenses
Training
Communication and counselling
Convincing power
Designs knowledge
Scientific Measurement Protocols
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Progressive lenses
Possible causes of problems with PAL’s
Indications
Contraindications
Scientific Measurement Protocols
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Scientific Measurement Protocols
Fields of view Direction of Gaze
Contraindications
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Mobility / Head Movement
Scientific Measurement Protocols
Contraindications
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Contraindications
Anisometropia High Cylinders Prisms High ADD
Scientific Measurement Protocols
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Contraindications
Bifocal users
Reading glasses users
Scientific Measurement Protocols
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Scientific Measurement Protocols
Measurements step by steps
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Step 1
Patients selection
Scientific Measurement Protocols
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Patients selection
Identification
Requirements
Expectations
Scientific Measurement Protocols
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Step 2
Frame selection
Scientific Measurement Protocols
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Scientific Measurement Protocols
Frame shape
Good Shape
Bad Shape
Good Depth Good Size
Too Large
Frame sizeFrame depth
Small frame
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Ideal frames Prefer metal frames
Adjustable nose pads
Min depth of 25-30 mm
Min fitting height should be 18mm / 14mm
Scientific Measurement Protocols
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Step 3
Frame Adjustment
Scientific Measurement Protocols
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Scientific Measurement Protocols
Frame Adjustment
Vertex distance
Pantoscopic tilt
Facial wrap
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Back vertex distance Shorter
Reduce BVD – wider fields of view
Scientific Measurement Protocols
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Scientific Measurement Protocols
Effect of vertex distance
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Pantoscopic tilt
10 to 12 degree
Pantoscopic tilt – increases near field of view
Scientific Measurement Protocols
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Scientific Measurement Protocols
Effect of Pantoscopic tilt
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Facial wrap – must not be too flat
Scientific Measurement Protocols
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Scientific Measurement Protocols
Effect of facial wrap
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Step 4
Interpupillary distance (IPD)
Scientific Measurement Protocols
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IPD
Monocular PD
Binocular PD
Scale or Pupillometer
Scientific Measurement Protocols
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IPD Use a corneal reflex for accuracy In case of strabismus – occlude one eye
Scientific Measurement Protocols
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Pupillometer centration
Scientific Measurement Protocols
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Effect of inexact IPD marking
Scientific Measurement Protocols
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Scientific Measurement Protocols
Step 5
Monocular PD marking in the lens
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Step 6
Fitting Height/ Vertical Height
Scientific Measurement Protocols
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Fitting Height Ensure that you are at eye level of patients Take monocular fitting height Measure directly to pupil centre Ensure that patient is looking strait ahead
Scientific Measurement Protocols
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Scientific Measurement Protocols
Fitting height
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Effect of wearer posture
Scientific Measurement Protocols
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Scientific Measurement Protocols
Effect of parallax error Parallax error can significantly affect fitting
height
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Effect of Fudging Fitting Height
Scientific Measurement Protocols
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Scientific Measurement Protocols
Step7
Check the lens cut out
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Scientific Measurement Protocols
Delivery ..
Quality check up
Markings
Frame alignments
Power
Fitting cross heights & PDs
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Scientific Measurement Protocols
Delivery ..
On eye assessment
Frame fit Fitting crosses
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Delivery
Scientific Measurement Protocols
Delivery Instructions
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Thank you