: How does Autorefractor work?


For those who didn’t know, it’s the device with [the image](https://images.app.goo.gl/C8wN9yCChZLbWVX26) you see during eye checkup

Quick google and youtube search tells me it relaxes your eye, but how does it measure anything about your eye?

In: 2


The autorefractor projects an image into your eye — that much is pretty obvious, since that’s how you see things!

But it also watches the image (or, more precisely, the light that makes up the image) as it bounces back out of your eye, and it uses this backscatter to generate a baseline determination of what sort of vision correction you need.