EEVblog 1554 - Optometrist AutoRefractor Keratometer TEARDOWN!

A teardown of a very interesting bit of optometry kit, a Shin Nippon NVISION K-5001 RefKeratometer (Auto Refractor Keratometer).
It can measure the curvature of your cornea, and well as refractive error to diagnose near and far sightedness.

Links:

00:00 - What is an AutoRefractor Keratometer?
03:41 - Don't try this at home kids! Can Dave measure his eyeball?
06:17 - Teardown
08:14 - Pupil distance measurement
09:43 - Should have read the manual...
11:22 - How the Keratometer mire circle is generated
13:42 - Optical path and lenses
15:47 - The camera
16:53 - Fine auto-focus mechanism
18:22 - Main PCB

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[johnmartin]

Hi Dave. I would totally love it if you could arrange that tour of the Optometrist's Office with all of the fancy high-tech optical equipment! John M.

[slappythesquirrel]

love to have a tech geek optometrist explain it

[sampofilms]

I lost use of my left eye after an accident while traveling in Japan in 2022 and they used this exact machine to scan my eye at the hospital! Interesting to see it in use/torn apart while not hopped up on those lovely Japanese painkillers. 👍

[robine]

As curious as I am about what's in those boxes, I am glad this wasn't a destructive teardown of this working machine. 👍🏼

[adamsiwek]

"Trust me I'm a professional", 1 sec later "I don't know what I'm doing" - pure gold.

[sudazima]

the measurement you did told you the cylinder astigmatism for your eyes, +1.00 right +0.75 left. not unusual for someone thats getting older. cylinder means if you stare at a streetlight at night it doesnt look like a point but it becomes a line at an angle. this is different from near sighted-ness where it essentially becomes gaussian blurry.

[KeritechElectronics]

You turned it on before taking it apart! I'd love to see the optometrist tour, preferably with teardowns :D
Interesting mechanical construction and definitely nice optics. Wonder what @IMSAIGuy and @mikeselectricstuff could say about it. And those colorful twisted wires, and anti-tamper enamel on screws... nice!

[MarianKeller]

To get an initial idea of how old the device is, the WEEE trashcan symbol on the label with the black bar indicates that it was made in or after 2005.

[natecontarino]

"That's not a Auto Refractor Keratometer, THIS is a Auto Refractor Keratometer!"
-Capacitor Dundee

[greme]

I love seeing the optometry teardowns, I suffer with bi lateral Pellucid marginal degeneration and have had my eyes scanned with so many pieces of kit I've lost count. The modern version of the machine at least here in the UK tends to show a hot air ballon on a desert road I guess some designer thought that would be a good image to focus upon. if you can come across an orb scan at the auctions I would love to see the internals on one of those. its used for measuring corneal thickness and produces a topographic map of the cornea.

[ray]

Watching this was awesome, it also led me to find someone other than Laubman & Pank this time around. Have been using L&P for the last 5yrs since I went for my first eye test, but I felt the old fashioned chair with the manual method of putting lenses in front just didn't work all that well.

Made an appointment for my local Specsavers last week which was this morning, put me through this machine and another one (that did a focus and pressure test), and found that the glasses I have weren't sufficient.

If it wasn't for this video, I would have just kept going to L&P.

Bonus is that my local shopping centre has L&P, Specsavers, and OPSM, 25min drive away here in the South-West of WA.

[andreaaverardi]

I repaired many of this equipments in the years of many productors, like Nidek, Canon, Kowa, shin Nippon.
Very interesting and complicated machines

[PelDaddy]

Love love a more in depth tear-down, perhaps in tandem with an expert in this particular field. Thanks for sharing.

[randalljohnson]

Eye guy here, most have some minor auto-aligning and focusing which is probably what a good bit if the fiddly bits inside are.

The joystick up/down movement is more accurate than the chin rest. So the chin rest isn't moved much unless someone has a watermelon for a head or you are testing a child.

[UnbornApple]

I love all of the stickers labeling ground.

[danpatterson]

The best papers I ever read on keratometry and other methods of corneal topography were written by Barry A.J. Clark in the 1970s. He figured it all out.

[p_mouse]

I love the idea of let a optometrist explain. Although having studied this stuff many many years ago, I really doubt they would allow it. but hey, who knows.
Even without fancy equipment it's not hard to measure your own prescription with just some super basic tools.
(That is slightly different when you have special needs for your eyes)
We used to do these experiments a lot back than as practice.

They make it seem a lot more fancy than it really is.
That having said, very interesting piece of equipment, a lot of smart engineering went in there!

[moyrml]

I was always intrigued by these machines as a kid. I kept wondering what good does it do for the exam when I stare at an image of a stop sign up a hill or a hot air balloon in the sky. Thanks! I would love to see you tear that thing apart AND a talk with you optometrist about it!

[qzorn]

Wow, something worth knowing about. 🤸‍♂ Now for some Keratometer videos. 😎 Thanks for the info.

[arthurskudra]

Definitely get a tour from a local office. I would love if you could get an in depth look at a visual field tester. It's about the closest piece of equipment in an optometrist's office to a video game, complete with button controller remote and moving light!! I have to get tested annually on this machine!