About this site

This site is part of a public library of interactive explanations. It is free, has no ads and needs no sign-up.

How the science is checked§

Every computational model behind a figure is tested twice: by its author against worked examples, and by an independent test suite written from the published equations and reference values, without reading the model's code. Every factual claim is recorded in a claims register with its source and checked by a reviewer who did not write it. What each figure simplifies is stated next to the figure.

Data and models§

The focusing eye is the thin-lens model of OpenStax College Physics, with the average amplitude of accommodation from Hofstetter's formula. Photoreceptor sensitivities are the Stockman and Sharpe cone fundamentals and the CIE scotopic and photopic luminous efficiency functions, taken from the Colour & Vision Research Laboratory database at University College London. The color-blindness simulation uses the published matrices of Machado, Oliveira and Fernandes (2009). Every drawing, including the eye diagram and the checker-shadow figure, is made for this site. Details and licences are listed in the project's asset register.

Not medical advice§

The blind spot, depth perception and color tools on this site are demonstrations on an uncalibrated screen. They cannot diagnose anything. Questions about your eyes or vision belong with an optometrist or ophthalmologist.

Found an error?§

Please open an issue on the source repository. Corrections are welcome and are credited.

Reuse§

Text and figures are licensed CC BY 4.0; code is MIT. Teachers may use and adapt any of it, with attribution.