Lensometer: Estimate Glasses

Estimate the power of single vision eyeglass lenses using your phone's camera and an Amsler grid.

Lensometer uses an on-device Core ML model to analyze a photo of an Amsler grid taken through an eyeglass lens and predict the lens prescription — including sphere, cylinder, and axis.

HOW IT WORKS

1. Display an Amsler grid on any screen by visiting AmslerGr.id in a browser, or use a printed Amsler grid.
2. Hold a single vision lens halfway between your phone and the grid.
3. Take a photo through the lens with the grid centered in the square overlay.
4. The app analyzes the image and returns an estimated prescription in seconds.

FEATURES

• AI-powered lens power estimation using a trained Core ML model
• Works with single vision lenses (not bifocals or progressives)
• Supports both positive and negative cylinder notation
• Spherical equivalent calculation
• Prescription history with automatic saving
• Camera overlay guides for grid alignment and lens positioning
• Fully on-device — no internet connection required

IMPORTANT DISCLAIMER This app is NOT FDA approved and has NOT been validated for clinical use. It does not replace a traditional lensometer or professional eye examination. Results should not be used for clinical decision-making or prescribing eyeglasses. This is an educational tool intended for rough estimation purposes only.