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