Eye Chart: Snellen & Amsler — Privacy Policy
Last updated: 2026-09-26
This privacy policy applies to the mobile app Eye Chart (listed on Google Play
as "Eye Chart: Snellen & Amsler" and shown on your device as "Eye Chart") on
Android and iOS:
- Google Play: package com.moon.eyechart, developer "janey-moon"
- Apple App Store: bundle ID com.moon.eyechart, seller "Heekyung Moon"
The app is developed and operated by Heekyung Moon (Google Play developer name:
janey-moon), referred to as "we" or "us".
Contact: ansgml2100@gmail.com
OVERVIEW
Eye Chart shows a Snellen letter chart or a Tumbling E chart sized for the
viewing distance you choose, after you match an on-screen line to 50 mm with a
ruler, and an Amsler grid. You can record the smallest line you could read.
Chart sizes are calculated on your device. The app does not require an account,
and we do not sell personal data. It uses Google services for analytics, crash
reporting, app configuration and advertising, as described below.
LOCAL DATA
The following are stored in the app's storage on your device:
- Recorded results (no set limit): for each result you record, the date and
time, the chart line (for example 20/40), which eye (left, right or both) and
the viewing distance with its unit (feet or meters).
- Calibration: the on-screen length you matched to 50 mm, the size of the chart
area it was matched on, and your last viewing distance, unit and eye choice.
It is removed when you tap "Recalibrate 50 mm line" or when the screen size no
longer matches.
- A short summary of your last recorded result (line, eye and distance) with the
time it was recorded; it is overwritten each time you record.
- Backup copies: if saved results are found to be damaged, or older saved data
has to be converted to the current format, the app keeps a copy of the
previous data on the device so it is not silently lost.
- App state such as cached ad settings and a cached list of our other apps.
The first-run distance unit is chosen from your device's measurement or region
setting, which is read on the device. The app does not use the camera and does
not measure your distance or your eyes; you set the distance and choose what to
record. The Amsler grid does not record anything. Your results are not uploaded
to our servers. Apart from the chart line noted under Firebase Analytics below,
they are not included in analytics events.
THIRD-PARTY SERVICES
- Google Firebase Analytics: app usage events (for example app launch, tab and
menu opens, a result being recorded, opening the privacy policy, our other
apps or the review option, and the response to the iOS tracking prompt), ad
revenue events (ad format and estimated value), device and technical
information and an app-instance identifier, used to understand how the app is
used. The "result recorded" event includes the chart line you recorded (for
example 20/40), but not which eye, the viewing distance or your list of
results.
- Google Firebase Crashlytics: crash reports and technical diagnostics, used to
keep the app stable.
- Google Firebase Firestore: the app downloads app configuration (ad settings
and a list of our other apps). It does not upload your data.
- Google AdMob: the advertising identifier (Android Advertising ID or iOS IDFA,
where permitted), device and network information, ad interaction data and IP
address (which may be used to estimate approximate location, even though the
app has no location permission), plus SDK diagnostics described in Google's
disclosures, used to show and measure ads, prevent fraud and diagnose ad
delivery. The app shows banner, full-screen (interstitial and app-open) ads
and, on the Android exit screen, a native ad. The app does not include other
ad networks through mediation.
Apart from device backups, the app sends data automatically only to the services
above, for the purposes above. We use these services under Google's applicable
terms, and we ensure that third-party service providers with whom we share user
data provide the same or equal protection of that data as stated in this policy.
See:
https://policies.google.com/privacy
https://firebase.google.com/support/privacy
https://policies.google.com/technologies/ads
ADS CONSENT & TRACKING
Where required (for example in the EEA and UK), the app first shows Google's
User Messaging Platform (UMP) consent message. Personalized ads are used only if
your choice allows them, or where no consent choice is required; otherwise, when
Google's consent status permits ad requests, only non-personalized ads are
requested. If the consent step fails (for example, the message cannot be
loaded), the app still requests ads, but only non-personalized ones, and does
not show the iOS tracking prompt.
On iOS, only after that step, and only when personalized ads are allowed, the
app asks for App Tracking Transparency (ATT) permission. If you do not allow
tracking, the IDFA is not available to the app or to Google, and the app
requests non-personalized ads.
Non-personalized ads still use limited device, network and IP information to
deliver and measure ads and prevent fraud.
Where a consent choice is required, the app menu shows "Privacy choices", which
reopens the consent message so you can change your choice. The menu also links
to this policy.
Analytics and crash reporting are not controlled by these ad choices.
PERMISSIONS
The app does not ask for camera, location, microphone, contacts, photo library,
health data or notification permissions. It uses internet access for ads,
analytics and app configuration, the advertising identifier as described above,
and vibration for button feedback.
DATA RETENTION & DELETION
- Recorded results: you can delete any result on the Results screen (tap the X,
then confirm). Deleting a result does not remove a backup copy described above
or the last-result summary; these are removed when you clear the app's data or
uninstall the app.
- Calibration: tap "Recalibrate 50 mm line" to remove it.
- Uninstalling the app removes its local data from this device; existing device
or cloud backups are handled separately (see below).
- Data processed by Google Firebase and AdMob is kept according to those
services' retention settings and policies. Uninstalling the app does not
delete data that was already sent to them.
- To request deletion of data associated with your use of the app, email us at
the address below. Because we do not ask for your name, email or account, we
may only be able to act on data we can link to you from the information you
provide, and we will explain any limits in our reply.
STORAGE & CONTROL
- Android: if device backup is enabled, app data may be included in your Google
backup and restored on reinstall. You can also clear the app's data in
Settings > Apps.
- iOS: app data may be included in your iCloud or device backups according to
your device settings.
- Android: you can reset or delete your Advertising ID in Settings > Google (or
Privacy) > Ads.
- iOS: you can change tracking permission in Settings > Privacy & Security >
Tracking.
SECURITY
Data sent to Google Firebase and AdMob is transmitted over encrypted (HTTPS/TLS)
connections. Local data is kept in the app's private storage area and is
protected by your device's operating system; the app does not add its own
encryption, so protect your device with a passcode. No method of transmission or
storage is completely secure.
IMPORTANT NOTICE
Eye Chart is for screening practice and personal notes only. It is not a medical
device, it does not diagnose any eye condition, and it does not measure your
prescription. The results you record are your own notes, not a measurement of
your vision, and chart sizes depend on your calibration and the distance you
set. If your sight changes suddenly, or you have eye pain, flashes or new
distortion (for example wavy or missing lines on the Amsler grid), see an eye
care professional promptly. Regular eye examinations by a professional cannot be
replaced by this app.
CHILDREN
This app is not directed to children under 13 and we do not knowingly collect
personal information from children.
CHANGES
We may update this policy; the "Last updated" date above will change.
CONTACT
Developer: Heekyung Moon (Google Play: janey-moon)
Email: ansgml2100@gmail.com