How does that gauge eye pressure?

So originally, there's a few ways.

So we always used to think that the blue light at the slit lamp or at the machine that looks at the front of the eye was the standard of care for IOP, but we're realizing now that that really is not always accurate.

A lot of things can affect that blue light, or we call Goldmann tonometry.

And you're absolutely right.

There als- um, there was also the puff, which is a pneumotonometer.

And more recently, probably within the last maybe 10 years, we've been using what's called rebound tonometry.

Right.