Effective date: August 23, 2026
What the Extension Does
VisionCircadian is a Chrome extension that estimates the circadian stimulus (CS) of the webpage you are currently viewing. It reads the colors of visible elements on screen, computes a photobiological score using established lighting science (CIE S 026:2018), and displays the result in the extension popup and toolbar badge.
Data We Do Not Collect
- No personal information (name, email, account details)
- No browsing history or URLs visited
- No page content, text, or images
- No usage analytics or telemetry
- No cookies or persistent identifiers
How Color Data Is Used
The extension reads the computed CSS background and text colors of visible DOM elements on the active tab. This color data is used exclusively to calculate the circadian stimulus score. It is processed in memory, never written to disk, and never sent anywhere outside your browser.
Permissions Explained
- activeTab — allows the extension to read color information from the page you are currently viewing, only while the extension is active.
- scripting — used to inject a small content script that samples element colors and applies the optional screen tint overlay.
- tabs — used to detect tab switches so each tab maintains its own independent exposure record.
Third-Party Services
VisionCircadian does not use any third-party services, APIs, or analytics platforms. No data leaves your device.
Children's Privacy
This extension does not knowingly collect any information from anyone, including children under the age of 13.
Changes to This Policy
If this policy changes in a future version, the updated policy will be published at this URL and the effective date above will be updated.
Contact
Questions about this privacy policy can be sent to voguri@asu.edu.