1.
Traditional
front surface design
Advantages
-
Variable base curve built in
-
Better cosmetics
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Good optical quality in all zones
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Proven technology
-
Accurate replication of design
-
Uses traditional equipment
Disadvantages
-
Requires large stock capacity
-
No customisation
-
Design limited to one surface
-
Optics further from the eye
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2.
Back surface
digital design
Advantages
-
Reduced stock capacity
-
Optics closer to the eye
-
Individualised
-
Customised
-
Superior optical precision
Disadvantages
-
Only one base curve available
-
Usually too convex
-
Only one surface to work with
-
Less cosmetic (mainly plus Rx)
-
Too close to the eye
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3.
Dual sided
digital design
Advantages
-
Optics closer to the eye
-
Individualised
-
Customised
-
Larger near area
Disadvantages
-
Larger stock capacity
-
Very complex to produce
(No margin for error)
-
Limited flexibility
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