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Professional optical calculation tools for opticians, students, and eye care practitioners.

Prism

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Prentice's Rule
Calculate induced prism from lens decentration
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Prism Resolver
Combine or resolve prism components
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Lens Power

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Lens Power
Calculate total lens power from front and back curves
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Lens Thickness
Estimate center and edge thickness of lenses
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Sag Formula
Calculate lens surface sag from radius and diameter
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Measurements

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Minimum Blank Size
Calculate minimum lens blank size needed for frame
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Prescriptions

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Vertex Distance
Compensate prescription power for different vertex distances
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Transposition
Convert plus cylinder to minus cylinder and vice versa
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Add Power
Calculate reading addition from working distance
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Spherical Equivalent
Calculate spherical equivalent of cylinder prescription
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OpticalToolbox

Free, modern optical calculators for opticians, optometry students, and eye care professionals. Professional tools made simple.

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Calculators

  • Prentice's Rule
  • Lens Power
  • Vertex Distance
  • Minimum Blank Size
  • Prism Resolver

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