Optometry

Optometry calculators for prescription conversion, lens fitting, visual acuity, IOL power, and eye care cost planning.

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Convert your glasses prescription to contact lens prescription using vertex distance adjustment for powers above ±4D.

Adjust lens power when changing the vertex distance (e.g., from glasses to contacts or between different frame positions).

Calculate prism diopters from measured displacement and distance. Uses the standard prism diopter definition and Prentice's rule.

Estimate center and edge thickness of eyeglass lenses based on prescription power, lens index, and frame size.

Calculate intraocular lens (IOL) power for cataract surgery using the simplified SRK/T formula based on axial length and keratometry.

Convert between Snellen fraction, LogMAR, decimal acuity, and MAR notation for visual acuity measurements.

Calculate the total annual cost of wearing contact lenses including lenses, solution, and eye exams.

Estimate your daily blue light exposure score based on screen time, brightness, device count, and blue light filter usage.

Determine if your frame is suitable for progressive lenses based on fitting height, frame dimensions, and add power.

Predict myopia progression over time based on current prescription, age of onset, and annual progression rate. Estimates adult stabilization.

Convert minus-cylinder to plus-cylinder form; axis rotates 90°.