Support

How to use

1. On launch, set the distance from your eyes to the screen (10–100 cm; default 50 cm)
2. Close one eye and tap the arrow that matches the direction of the gap in the Landolt ring (“C”)
3. Each correct answer makes the ring smaller. The gap faces one of 8 directions (45° steps), and from 0.5 upward a stage clears after two correct answers in a row
4. A wrong answer reports the last stage you fully cleared

If you answer wrong at the very first stage (0.1), no result is shown yet: the app retests with larger rings in 0.01 steps from 0.09 down to 0.01, and the first stage you read correctly becomes your result (if every ring is answered wrong, the app reports that acuity below 0.01 could not be measured).

Distance and measurable range

The upper limit follows “distance ÷ 50” (1.0 at 50 cm, 2.0 at 100 cm). For distances of 60 cm or more, we recommend two people: one holds the device, the other answers. Levels below 0.1 are measured in 0.01 steps during the retest that follows a wrong answer at the first stage (0.1).

FAQ

• Are results saved? — Only with the one-time premium purchase (in-app purchase): results are saved locally on your device with a trend chart and are not sent automatically. Premium users can export a CSV and choose where to share it. Without it, your last 7 measurement records are kept on the device (the record list works for free; the trend chart and CSV export are premium). Distance and reminder preferences, the last check date, and streak count are stored on the device.
• Can this replace an official eye exam? — No. It is a quick self-check for everyday eye strain. If you have any concerns, please see an optometrist.
• Can I start a check from Siri or Shortcuts? — Yes. You can open the test screen directly from Siri, Spotlight, or the Shortcuts app (just say “Start a vision check” to Siri). Combined with a shortcut automation, you can start a check at the same time every day. The test only advances with your taps, so nothing is measured on its own.
• The ring looks different across devices — Ring size is automatically adjusted for your device’s display (verified remaining deviation: within about 1%). This is a simple self-check, not a substitute for a professional eye examination. For day-to-day comparisons, we recommend using the same device.
• What is ring size calibration? — In Distance Settings → “Calibrate Ring Size”, you can align the short edge of a bank-card-sized card (credit cards, driver’s licenses, and insurance cards are all the same standard size) with a bar on the screen to correct the small remaining deviation of the automatic per-device adjustment. The correction factor is stored on your device only and is never transmitted. Automatic adjustment alone keeps the deviation within about 1%, so calibration is optional.
• I feel unwell while using the app — Stop using it immediately.

Contact

Feedback and bug reports: takezou621@gmail.com