Clinical Optometry Calculator Suite
A comprehensive dashboard of 20+ optical calculators and converters for optometrists, students, and eye care professionals.
Available Modules
Select a category to filter the tools below.
Vertex Distance Calculator
Calculate effective power at a different vertex distance.
Keratometry to Base Curve
Convert keratometry (D) to a base curve (mm).
LARS Rule Calculator
Adjust axis for a rotated toric contact lens.
Magnification (Distance) Calculator
Calculate required distance magnification.
Magnification (Near) Calculator
Calculate required near magnification from N-notation.
Kestenbaum's Rule
Estimate the required near add for low vision patients.
Retinoscopy Working Lens
Calculate the required compensating lens power.
Simple Transposition Tool
Transpose a prescription and determine astigmatism type.
Spherical Equivalent Calculator
Calculate the best vision sphere (BVS).
Visual Acuity Converter
Convert between different visual acuity notations (Snellen, LogMAR).
Retinoscopy Rx Converter
Finalize your working distance. Convert retinoscopy findings into a final prescription.
Snellen Letter Size Calculator
Calculate the size of Snellen letters based on chart distance.
Amplitude of Accommodation Calculator
Calculate amplitude from NPA or vice-versa.
Hoffstetter's Amplitude
Calculate expected amplitude of accommodation based on age.
Presbyopia Addition Calculator
Calculate near add based on working distance and NPA.
AC/A Ratio (Heterophoria)
Calculate the AC/A ratio using the heterophoria method.
AC/A Ratio (Gradient) Tool
Calculate the AC/A ratio using the gradient method.
Sheard's Criterion Calculator
Calculate the required prism using Sheard's criterion.
Percival's Criterion Calculator
Calculate the required prism using Percival's criterion.
Bielschowsky Head-Tilt Test
Identify the paretic cyclovertical muscle.
Developed by a Contact Lens Specialist
Shivashangari M
Masters in Optometry | Contact Lens Specialist
"Unlike generic online calculators, the Focus Links Optometry Calculator Suite is developed by Shivashangari M (Masters in Optometry). These tools are verified for clinical accuracy and designed to adhere to standard optometric formulas (ANSI)."View Profile