Library
Every sandbox
Filter by domain, search, or sort. The domains are just a way in — nothing here is locked or ranked.
Power Cross & Transposition
Convert between power cross and sphero-cyl, transpose, combine, and find the spherical equivalent.
Open sandbox
Retinoscopy
Sweep the streak, read the reflex, find neutrality.
Open sandbox
soonAccommodation & the Near Response
Accommodative demand versus amplitude as the target nears.
soonDuochrome
The red-green endpoint and the over-minus trap.
soonJackson Cross-Cylinder & Cylinder Refinement
Refine cylinder axis and power; watch the power vector converge.
soonSpherical Ametropia & Spectacle Correction
Far points, correcting lenses, and the effect of vertex distance.
soonVisual Acuity & Optotype Design
Subtended angle, minimum angle of resolution, and where 20/20 comes from.