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grue

Any eye docs around?

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How is it that the phoropter, aka "interchangable flippy spin mclens goggle thing", has not yet been replaced by something that doesn't depend on the patient's ability to reliably differentiate between "which is better"?

I'd have figured by now that there'd be some sort of scanning unit that goes "ah yes, with your eye scan, you need with "?

Or does the absolute shape/build quality (for lack of a better term) of the eye only matter to an extent, and how the brain choses to interpret the signals it receives matters as much as the physical side?



This thread spurred by having an eye exam, obviously :P Prescription hasn't changed in the decade I've been wearing contacts, about time for LASIK I reckon… and speaking of, isn't that EXACTLY what the wavefront system for LASIK does?
cavete terrae.

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There is such a machine. My optometrist uses it in the preliminary exam, (done by her assistants), before doing the fine testing with the "interchangable flippy spin mclens goggle thing".
"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

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ryoder

There is such a machine. My optometrist uses it in the preliminary exam, (done by her assistants), before doing the fine testing with the "interchangable flippy spin mclens goggle thing".



If only they had a machine like they used to have at the shoe store where you could look in the visor and see an X-ray of your kid's feet to make sure the shoes fit.

:D
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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AggieDave


If only they had a machine like they used to have at the shoe store where you could look in the visor and see an X-ray of your kid's feet to make sure the shoes fit.

:D



Here you go: http://www.youtube.com/watch?v=wbMN6jueU1A:D
"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

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the flippy lens asking which is better is used to refine near sighted reading.
Presbyopia is a condition that oldies like me get, the flippy lens helps determine if I need reading glasses aswell as normal specs.(or miultifocal lenses)
in Presbyopia the lens of the eye losses some of it flexibility for fine tunning your sight up close. not sure what machine could assess that.

All the above is my limited understanding of it and may well be total bollocks.

Pregrinerose, is an Opto Doc, maybe she can better explain it
You are not now, nor will you ever be, good enough to not die in this sport (Sparky)
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No but I had lasik a while back. They just scanned my eyeball with a couple of... scanners (NOT an eyedoctor!) and built a map of where it needed shaving using software. Mapping things with software I understand.

They're probably not more prevalent due to patents. IP is expensive. Non-wavefront lasik there was $500. Wavefront custom laisk there was $2000. The difference was probably mostly software licensing for the software to map my eyeball.

Presbyopia is a different beast and it sucks. Despite better than perfect vision in one eye and perfect vision in the other, I'm going to need reading glasses pretty soon now. I was hoping they'd be able to fix that by now *frowns at the optometrist profession as a whole*. Soon as I can get a HD glowing terminator eyeball, I am SO THERE.
I'm trying to teach myself how to set things on fire with my mind. Hey... is it hot in here?

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Iago

This one is cool. Takes a digital picture of your retina. Good for people who are diabetic or at risk for other retinal problems.
Not a total replacement (still need the dilated exam) since it can miss the edges.

http://www.optos.com/en/Professionals/Additional-resources/Product-description/optomap-retinal-examination/



I had that done as a "baseline," when I turned 50. That way, any changes as I get older, will be quantifiable.

But, as far as someone scanning your eye, and giving you glasses or contacts and saying "here you go, this is your perfect vision," there are too many variables that rely on personal comfort and tolerance. I have contacts fitted for "monovision," meaning I have one for distance (my right) and one for close work (my left). I love not having to deal with reading glasses! :)

I recently looked into lasik, and if I get it done, it will be with monovision.
lisa
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Almost all eye docs have an autorefractor that we use before the phoropter. It measures the shape of the front surface of the eye as well as bouncing light off of the retina to get it in focus for the machine. If it's in focus for the machine, it's in focus for you.

Why still use the flippy thing? Lots of reasons....

1. Although the autorefractor gives one point of focal vision, your visual field is a lot broader than just one point, and the prescription and aberrations of the eye change away from the very center. The flippy thing is used for more of a greater field of view, and much more functional. The wavefront LASIK takes the more peripheral aberrations into account and compensates for them (not everyone has enough peripheral aberration to warrant the extra cost of wavefront LASIK, but for those that do, it makes a big difference).

2. Vision is more than simple physics. There is also visual interpretation, and that can affect preferred prescription as well.

3. Binocular vision... for those of us with two eyes, the eyes have to work together as a team, that also affects the prescription in the glasses and the flippy thing can check for binocular balance, to ensure that the eyes are working together as a team. I also check eye alignment with the phoropter. If the eyes have a tendency to not work quite together, or not like to stay lined up, I can quantitatively measure the drift tendency and compensate for it with prism. That alleviates eyestrain in people with this problem.

4. Near vision. Lots of things affect near vision. With so many kids on ADHD meds, and all of the meds make it tougher for them to change their focal distance from far to near, they end up needing bifocals to compensate for this (and sadly, not all eye docs know to check for that side effect and pediatricians are not educating parents/patients about it). Plus presbyopia (getting old) and needing bifocals. Plus a lot of other focusing related issues, none of which are simple physics to measure, all get checked in the phoropter with the near point rod.

Hope that helps.... if it makes you feel better, about 80% of the time, I know the 'right' answer to which is better and am simply testing the patient's reliability in taking the test. I like to make sure that the patient is consistently picking the same lens combination before they sink money into a prescription (whether glasses, contacts, or refractive surgery). There are also kids that pretend they need glasses even though they don't, and kids that pretend they don't need glasses even though they do. I can be really sneaky with a phoropter when I need to be to ferret out those kinds of problems :)


Do or do not, there is no try -Yoda

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