Tonometry
This is a test that measures the pressure inside each eye. There are a variety of instruments used by healthcare professionals to do this. Some send small puffs of air against each eye. The air bounces back to the tonometer and gives the machine a reading of the pressure inside the eye. Others involve contact with the eye.
![Tonometry](/media/filer_public_thumbnails/filer_public/0b/75/0b75b9d9-ea05-4bb9-b9a8-20a3c5edd4e1/tonometer_image.png__1520x1012_q50_progressive_subsampling-2_upscale.png)