Clinical Calculators

Chairside and research tools: vertexing, prism, acuity conversions, etc.

Vertexing

Contact Lens Vertexing

Calculate contact lens power from a spectacle Rx.

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Reverse Vertexing

Calculate a spectacle Rx from a contact lens Rx.

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Double Vertex

Calculate lens power given two vertex distances.

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Refraction & Cylinder

Rx Analyzer

Full spectacle Rx workup: vertex, transpose, SE, trial CL, estimated VA.

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Plus-Minus Cyl Converter

Convert between plus and minus cylinder form.

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Spherical Equivalent

SE from sphere and cylinder, with quarter-step rounding.

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Retinoscopy

Convert neutralizing lenses and beam angle to plus/minus cyl.

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Amplitude of Accommodation

Convert cm to Diopters and compare to Hofstetter's norms.

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Visual Acuity

VA From Letter Size

Visual acuity from letter size and distance.

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Scalable VA Chart

On-screen acuity chart calibrated to your monitor and distance.

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Cycles/cm to VA

Visual acuity from cycles per centimeter and distance.

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VA Notation Converter

Snellen ft/m, logMAR, decimal, MAR, and M units.

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Contact Lens & Cornea

Base Curve

Convert base curve units (mm and diopters) or use a chart.

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Javal's Rule

Estimated residual astigmatism from corneal Ks.

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Prism

Oblique Fresnel

Magnitude and orientation of oblique Fresnel prism.

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Simulators

Vision Simulator

Simulate astigmatism, floaters, diplopia, scotoma, and more on an eye chart.

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Astigmatism Simulator

Meridional blur with adjustable axis and severity.

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Floaters Simulator

Drifting vitreous floaters, animated.

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Visual Snow Simulator

Flickering static across the visual field, animated.

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Diplopia Simulator

Binocular and monocular double vision in any direction.

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Central Scotoma Simulator

Central vision loss as in AMD, on chart or Amsler grid.

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Chromatic Aberration Simulator

Color fringing from lens dispersion.

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Metamorphopsia Simulator

Wavy-line distortion on the Amsler grid.

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Peripheral Field Loss Simulator

Constricted fields as in glaucoma or RP.

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References

ICD-10 Eye Codes

Searchable eye-care ICD-10-CM codes (FY2027) with billable flags.

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