Privacy Policy

Camera and photo data

PD Measure is a measurement tool that can use your webcam or a photo you choose to upload in order to detect your pupils and a reference card. This processing happens entirely inside your web browser using on-device machine learning (WebAssembly/WebGL). Your camera frames and any photo you select:

• are never uploaded to us or any third party;
• are never stored on a server — there is no backend that receives them;
• exist only temporarily in your device's memory while you measure, and are discarded when you leave or refresh the page.

The numerical result (your PD in millimetres) stays on your device too. If you choose to use the “copy shareable link” feature, only the numbers you decide to share are encoded into a URL that you control — no image data is ever included.

What we do not collect

• No account, email address, or sign-up is required or requested.
• No images, biometric templates, or facial data are transmitted or retained.
• We do not sell or share personal data, because we do not collect it.

Third-party assets

To run the measurement, your browser downloads a machine-learning model and runtime files (for example from a public CDN) and a web font. These requests fetch static files so the tool can run locally; they are not used to send us your image. Once loaded, the tool also works offline.

Analytics

We may use privacy-respecting, aggregate analytics (such as Google Analytics) to count page views and understand which guides are useful. Analytics never receive any image or camera data. If a measurement-specific analytics tag is ever added, it will only record that a measurement occurred — never the image or the underlying pixels.

Cookies and local storage

The core tool does not require cookies to function. Any analytics provider we use may set its own cookies; you can block these in your browser without affecting the measurement tool.

Children

This tool is intended for general use in measuring PD. For measuring children's PD, or for any clinical need, please consult a licensed optician.

Changes and contact

We may update this policy as the tool evolves; material changes will be reflected here with a new “last updated” date. Questions about privacy? Reach us via the contact page.