Lenses have spherical and prismatic properties. The prismatic property is ability to redirect light. However, prismatic effects do not occur in the center of the lens. For this reason, while mounting lenses to your frame the center of the lens should be exactly on your pupilla. So pupillary distance is a value we need to know while preparing your glasses to give you a more comfortable view. If your ophthalmologist has already prescribed this value on your prescription, you do not need to measure it. Otherwise you should use our free tool to measure this value.

The logic of our tool is quite simple.

  1. The credit card has universal dimensions. Its 85.60 mm × 53.98 mm. We already know this value. Place an object, such as a credit card, a loyalty card, or a subway card, over your chin and take the picture. Make sure the photo is taken symmetrically and straight.
  2. On this tool  there is 2 circles. One for right pupilla, one for left pupilla. Place the circles in the center of each pupilla.
  3. Than click "Calculate" button. The distance between 2 circles will be proportioned to credit card length.
  4. Voila! Your pupillary distance is calculated. +/-1mm is in tolerance.

click here to use our online pupillary distance measurement tool.

To have more information you can check our youtube video.