For more than a century, scientists have understood that three factors control pupil size: light, focus distance, and ...

It was previously believed that our pupil size was only affected by three things: light, focusing on nearby objects and ...

A pupil distance meter is a device used to measure the distance between a person’s pupils before they are fitted with glasses, in order to ensure the lenses are centred in the visual axis.

Researchers at Karolinska Institutet in Sweden have discovered a fundamental mechanism that affects the size of the pupil, ...

The Reichert PDM Digital PD Meter utilizes the latest technology for measuring interpupillary distance and right/left pupil-to-nose distance. The PDM's ergonomic design, smooth action, and user ...

Users of stronger optical inserts in particular complain of headaches after using Vision Pro. Sometimes changing the settings helps.

Make a note of where the top of pupil one's thumb is on the ruler in centimetres. And record the distance in the pupil's reaction times chart. Repeat the test five times for each pupil.