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Making My Own Glasses

eidel.io

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Re: Making My Own Glasses

#111

Post by JoeAltmaier »

astura wrote: post #110
djhworld wrote: post #27

Earlier quoted context omitted.

Not sure about legality but here in the UK you will find opticians will give you your prescription, but often exclude the pupil distance measurement (I think) which a lot of the online stores require. I think you can ask for it, but they will only give it begrudgingly.

That's cause PD is measured by the optician separately when you're ordering your glasses, not by the optometrist or opthalmologist who writes the prescription. In other words, it's not part of the prescription, it's instead part of the glasses fitting process. A non-eye related example would be if your doctor prescribed you a brace and the person at the medical supply store measured you to find out which size you nee…

...and can be measured at home using a ruler and a mirror, pretty simply. Close one eye, align the ruler at 0 under that pupil. Open the other eye, close the first, read off the distance to the 2nd pupil.

Re: Making My Own Glasses

#113

Post by nsxwolf »

JoeAltmaier wrote: post #111
astura wrote: post #110

Earlier quoted context omitted.

That's cause PD is measured by the optician separately when you're ordering your glasses, not by the optometrist or opthalmologist who writes the prescription. In other words, it's not part of the prescription, it's instead part of the glasses fitting process. A non-eye related example would be if your doctor prescribed you a brace and the person at the medical supply store measured you to find out which size you nee…

...and can be measured at home using a ruler and a mirror, pretty simply. Close one eye, align the ruler at 0 under that pupil. Open the other eye, close the first, read off the distance to the 2nd pupil.

Did this for my wife recently. We measured multiple times very carefully, and got it very wrong.

Re: Making My Own Glasses

#115

Post by AdrianB1 »

gvb wrote: post #34
AdrianB1 wrote: post #13

For more than 10 years I am going to the same optician for glasses. As a sport pilot, I need to have 2 pairs at all times (one is kept as reserve in the cockpit); changing one to another, with identical "everything", produces a serious discomfort that I cannot explain. I learned to live with the idea that eye sight is complicated. Measurements at different points in time can differ slightly: in the morning just after…

I suspect the discomfort when switching glasses is that the inter-ocular distance is different between the two glasses (one is likely right or "more right"). You have the right correction, but it is off-axis WRT your pupils with one pair. When I go to my $$$ optician, the technician marks my pupils on the blanks in the frame that I've selected using a sharpie (before the glasses are made) and adds the inter-ocular me…

My optician friend is doing the inter-ocular distance right, he showed me the process while he was cutting the lenses on a high-end computerized machine. But the only difference between my glasses are the frames, there are some differences in the frames that makes a difference in the final product. I guess it is the angle between the lenses, even a small difference can be creating the discomfort. It takes me a few hours to adjust.

Re: Making My Own Glasses

#116

Post by petschge »

SamBam wrote: post #103
iamthepieman wrote: post #8

Earlier quoted context omitted.

Since vision happens mostly in the brain, simply selecting a lens which focusing light at a certain point in your eye is not the only thing to optimize for. You also have to optimize for the processor behind the sensor which, at least until more advanced vision models are made, is going to be purely subjective.

Is it possible for the lens to focus light perfectly, and the brain to process that as blurrier than if the light were focused imperfectly? I would imagine that, no matter how the brain were processing the image, the image being focused exactly on the retina is an objective truth, and that an exactly-focused image must be clearer to the brain than a blurry image.

That is true for the spherical part of the lens. When you start to look into the correction of astigmatism (done by the cylindrical component of the lens) it become a whole lot more complicated.

Re: Making My Own Glasses

#117

Post by rozab »

wonderwonder wrote: post #22
emptybits wrote: post #5

Fascinating hacker story in an unexpected domain. Thank you! A side note about "getting your numbers"... The author remarks, "she’s not happy to share the measurements with me as she fears I’ll run off and get my glasses made online". This will obviously vary by jurisdiction but what the author describes may be illegal in some places. e.g. where I live, there is a law since 2010 requiring opticians and optometrists "…

This did strike me as strange. Imagine going to a doctor getting a blood test and being told your numbers are good or bad but the doctor refusing to give you the actual result. They are your results, you paid for them and are part of an overall need to understand your health.

I don't know about the US (I thought HIPAA was very comprehensive...?) but in the UK you are legally entitled to view personal data about yourself. It wouldn't matter if you paid for the test or not, if it's on file you should be able to access it.

Re: Making My Own Glasses

#118

Post by astura »

diroussel wrote: post #79
tonyarkles wrote: post #50

Earlier quoted context omitted.

I encountered this in Canada, with an explanation given to me that there was a lawsuit at some point where an optometrist was sued after a client ordered glasses elsewhere based on the provided IPD and got glasses that caused headaches or something like that. From Wikipedia[1]: > In both the UK and most of Canada (excluding British Columbia[5]), the PD measurement is classed as a dispensing tool rather than a part of…

As part of GDPR you can request a copy of any personal data. In the UK this is governed by the ICO, and it’s called Right of Access. https://ico.org.uk/for-organisations/guide-to-data-protectio...

You get your PD measured at the time you order your glasses. If you never order glasses they'll never measure your PD.

Re: Making My Own Glasses

#119

Post by SAI_Peregrinus »

olieidel wrote: post #90
jaclaz wrote: post #87

Earlier quoted context omitted.

If I may, particularly as a doctor yourself, you should call the eye doctor "ophthalmologist", as you surely know if you use "part of the body + doctor" there might be issues should you report a visit by a "proctologist" ...

Haha! Good point. I guess I thought "eye doctor" made for easier reading, assuming not everyone knows that ophthalmologist == eye doctor.

The way I typically like to use terms of art in writing is to write the term out first, and then a parenthetical with a definition. For example here you went to see an ophthalmologist (eye doctor). It's also good for acronyms and initialisms.

Re: Making My Own Glasses

#120

Post by logfromblammo »

Androider wrote: post #106

I wonder if the use of a lensmeter makes you fall into a local optimum while missing out on a potential global optimum? Let's say I go to a bad optician and get a pair of lenses that have something way off like the cylinder is the wrong way around, or toric lenses for astigmatism when you actually don't have it. Everything looks like crap but then you get used to it (the brain is amazing at adapting). Then a few year…

You can calculate a spherical-only prescription from an astigmatism prescription. Order cheapest-possible glasses using those lenses, and wear them for a while before visiting a new optometrist. Leave them behind before you go in, and say you lost your glasses in the ocean, or they got crushed under a truck tire, or something. If you end up with a prescription that has a cylindrical component, and it has the same axis and magnitude as your previous prescription, then you have an objectively-measured, independently-repeated astigmatism.
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