- How to notice when one eye has got worse than the otherThe better eye hides it · cover one eye at a time · repeat the same way
- Reading a visual acuity number: 20/20, 6/6, decimal and logMARSnellen · metric 6/xx · decimal · logMAR, in one conversion table
- Home eye testing: test distance, screen calibration and lightingSize follows distance · calibrate with a bank card · what it cannot fix
- Near vision self-check and how to read J, N and M notation40 cm reading distance · J1 to J16 and N points · dioptres come from the clinic
- The limits of a colour blind self-test, and how job or licence standards are decidedDot plates screen · arrangement tests grade · standards belong to the authority
- How to use an Amsler grid and what a wavy line means33 cm · one eye at a time · fixate the centre · change is what matters
- Why night driving is hard with normal acuity — contrast sensitivity and glareAcuity is size · night is faint detail plus headlights · measure them apart
- The evidence behind the 20-20-20 rule for screen eye strainBreaks help while you take them · the numbers are not from a trial · adherence is the variable
- Astigmatism self-check, the axis in degrees, and reading a spectacle prescriptionWhy a fan chart reveals it · axis runs 0 to 180° · what SPH, CYL and AXIS mean
- Checking a child’s vision at home and when to see an eye doctorOne exam between 3 and 5 · home checks are a prompt · amblyopia has a window
EyeCheck: Vision & Color Test
No sign-up, fully offline. A free Android eye self-check app that tests and records your left and right eye separately.