Interactive tools
Vision tools & eye tests
Educational acuity charts, prescription explainers, measurement guides, and calculators. Results depend on screen conditions and are not a substitute for a clinical eye exam.
Visual Acuity Tools
Educational charts and explorers that help you understand common distance and near acuity notations.
Visual Acuity Test
Educational on-screen eye chart to explore Snellen-style acuity lines — not a clinical examination.
Near Vision Test
Explore near reading clarity with an educational near-vision chart and learn why working distance matters.
Snellen Converter
Convert between Snellen 20/xx, metric 6/xx, decimal acuity, and logMAR for learning — not diagnosis.
Astigmatism & Color Vision
Screen-style educational checks for astigmatism patterns and color vision differences.
Prescription & Measurement Tools
Explainers and measurement helpers for glasses prescriptions, PD, frame size, and reading ADD.
Pupillary Distance
Learn what PD means, explore single vs dual PD, and practice educational measurement concepts for glasses fitting.
Prescription Decoder
Paste or enter OD/OS sphere, cylinder, axis, ADD, prism, and PD to get plain-English educational explanations.
Reading ADD Explainer
Learn what ADD means for progressive, bifocal, and reading lenses — educational ranges only, not a prescription.
Frame Size
Decode eye size, bridge, and temple measurements such as 52□18 140 and learn how frame fit works.
Educational Calculators
Diopter, distance, thickness, and acuity calculators for learning — not clinical prescribing.
Screen Distance
Estimate ergonomic viewing-distance ranges for monitors and TVs based on size — educational comfort guidance.
Reading Distance
Relate reading distance to diopters educationally (D ≈ 1/f) and understand near-work ergonomics.
Diopter Calculator
Calculate diopters from focal distance and explore optical power concepts without false acuity conversion claims.
Lens Thickness Estimator
Rough educational estimates of lens edge/center thickness from power, index, and eye size — labeled estimate only.
20/20 Vision Explorer
Interactively explore what 20/20 and other acuity notations mean — clarity concepts without false prescription mapping.
Vision Simulator
Illustrative simulations of blur, astigmatic distortion, glare, and contrast reduction for learning only.
Symptom Explorer
Educational pathways for common vision symptom patterns — not a diagnostic algorithm or triage bot.