$0
Free software, no subscription
Free · Offline · Built by an ophthalmologist
A real eye chart on a $15 stick.
Acuity Station turns an inexpensive streaming stick into a calibrated digital acuity chart on any monitor or TV. No account, no subscription, and fully offline once it is set up.
Install codes · 8088591 chart · 2261676 launcher
True size
Calibrated to your exact screen
Offline
No internet after setup
~15 min
One-time setup
What's inside
Every chart the lane needs, in one screen.
The full set of optotypes plus the common adjuncts, each sized to true physical dimensions on your display so acuity reads accurately at any distance.
R
Sloan letters
The standard NAS-NRC letter set for adult acuity.
7
Numbers
Numeric optotypes for patients who do not read letters.
E
Tumbling E
Direction-based testing, language independent.
C
Landolt C
Gap-orientation optotype to ISO geometry.
Duochrome
Red-green balance check for refraction.
Amsler grid
Central field screening for distortion.
Color vision
Pseudoisochromatic plates for color screening.
Astigmatic dial
Radial lines for axis and astigmatism cues.
How it works
A streaming stick, turned into a single-purpose chart.
Installing the chart directly on the device, as its own home screen, is what keeps it cheap and reliable. The app store is not trying to connect, the internet cannot interfere, and nothing else loads.
STEP 01
Plug in a stick
A Google TV streaming stick (the onn. is about $15) into any monitor or TV with HDMI.
STEP 02
Load the app
Install the free Downloader app, then enter two short codes to load the chart onto the stick.
STEP 03
Calibrate
Match the on-screen card to a real credit card, then set your lane distance. Sizes become physically true.
STEP 04
Set it as home
The stick now powers on straight into the chart and runs entirely offline. Driven by the remote.
Setup
Up and running in about fifteen minutes.
There is no link or file to download to your computer. The chart loads directly onto the stick using the two codes below, entered in the Downloader app on the device itself.
- Set up the stickPlug it into HDMI, power on, and finish the normal Google TV setup. A basic Google account is fine.
- Install DownloaderFrom the app store, install Downloader (by AFTVnews). It is free, and it is what loads the chart.
- Allow installsIn Settings, open About and click Build seven times to become a developer, then turn on Unknown Sources for Downloader.
- Enter the two codesIn Downloader, type each code below, select Go, and choose Install. Deleting the downloaded file afterward is optional.
- Calibrate the chartOpen Acuity Station, hold a credit card to the screen and match it to 85.6 mm, then set your patient distance.
- Make it start automaticallyOpen Launcher Manager and set Acuity Station as the home launcher. It now boots straight into the chart.
See it running
The real interface, in motion and still.
A short highlight reel on a calibrated screen, then the actual charts and tools exactly as they appear in the lane.
Highlight reel · the letters chart, lane calibration, optotypes, and color plates
ETDRS chart · logMAR scale, line isolation, per-eye tracking
Calibration · match the bar to a real card
Isolated optotype · live Snellen and logMAR readout
Numbers · for non-letter readers
Landolt C · orientation-based acuity
Duochrome · red-green refraction balance
Astigmatic dial · axis and astigmatism cues
Colour vision · pseudoisochromatic plates
Amsler grid · central field, with fixation dot
Questions
Before you ask.
The things colleagues check first.
Which device do I buy?
Any Google TV or Android TV streaming device. The onn. 4K box (about $20 at Walmart) is the cheapest certified option, but most Google or Android TV sticks and boxes work the same way.
Why not a Fire TV stick?
Amazon now blocks setting a custom app as the home screen on Fire TV, and its newest models block installing outside apps entirely. A Google or Android TV device avoids both problems.
Do I need internet?
Only for the one-time setup, to install the app. After that it runs fully offline. No account, no login, no subscription.
Is it really free?
Yes. It was built by a practicing ophthalmologist for his own exam lanes and shared as it is. No ads, no data collection, nothing to buy.
Is it accurate on any screen?
Accuracy comes from a one-time calibration. You hold a standard card to the screen, match an on-screen bar to it, then enter the measured test distance. Optotype sizes are then correct on any screen. A larger screen simply gives more room for big low-vision optotypes.
Does it store patient information?
No. It does not collect, store, or transmit any patient or personal data. It is a chart display and nothing more.
Before clinical use
Acuity Station is provided as-is, with no warranty. Confirm the calibration yourself against a physical card, ideally with a ruler, before relying on it. Treat the chart as an adjunct to your own clinical judgment, not a replacement for a certified or validated chart.