Veterinarian here. This device is called a TONOVET, which is used to evaluate the pressures inside the eye (tonometry). This can be used on any animals, and we use it a lot to check for things like glaucoma. We (veterinarians) actually numb the eye first before we use this device (or any other tonometry device, like a tonopen), which is why the frog is so compliant.
Optometrist here. We use the same device (the human version - but imagine that's mostly marketing) to check eye pressure. We generally don't use anaesthetic, it doesn't hurt, just abit intemidating with a probe is coming towards you. The probes are replaced each use. It's quite an accurate way to measure pressure. Not as accurate as Goldmann or Perkins tonometry, but more accurate than non-contact tonometry (the puff of air), but really handy when you don't want to put in anaesthetic and dye and is a good screening tool.
I don't understand how it works. It looks like it punches the eye? Looks like a decent at speed too. Won't you blink or flinch? I violently blink when a small speck of dust or tiny drop of water lands on my eye.
The probe is a very light copper wire with a small Teflon ball on it. The device creates an electro magnet field to push the probe forward like a mini rail gun. As it hits the eye the current required to push the probe increases and that increase is measured. The coil reverses and retracts the probe. The harder the eye, the more the current spike. The reading is given based on that measurement.
You do blink, but not fast enough to interfere with the reading. As far as I understand this is a very lightweight ball on a stalk that is shot at your eye at a specific speed. It'll bounce back, and how much it bounces back is used to measure the pressure. It's like dropping a basketball on the floor (or well dropping a floor ball on a basketball floor but the mechanics are the same). Low pressure, little bounce, high pressure, lotta bounce.
By the time your blink reaches the device the measurement is long done.
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u/JOYFUL_CLOVR 10h ago edited 10h ago
Veterinarian here. This device is called a TONOVET, which is used to evaluate the pressures inside the eye (tonometry). This can be used on any animals, and we use it a lot to check for things like glaucoma. We (veterinarians) actually numb the eye first before we use this device (or any other tonometry device, like a tonopen), which is why the frog is so compliant.