Making My Own Glasses • Hacker News Board

Re: Making My Own Glasses

#31

Post by coldtea » Fri, Oct 04, 2019, 1:10 PM UTC

>I have a few seconds to decide whether I see some letters better and this decision will decide which lenses I’ll have in my glasses for the next few years? Absurd!

On the contrary, it seems totally logical. If the difference is so small that you can't assuredly decide between two options, either will do.

>How can a trustworthy decision be made in this not-real-life scenario of staring at letters on a wall? I want to be able to decide while going about my daily routine: Staring at computer screens, looking out of the window, looking into space. My daily routine doesn’t include staring at the same five letters projected onto a white wall and reading them out loud.

Yeah, so? Who told you you'll find anything more doing that, that you would looking at the projected letters?

>I went through with it and the pair of glasses arrived around two weeks later. Putting them on for the first time, my vision was just as perfect as with the trial lenses. Awesome! This was hands-down the best pair of glasses I ever had. Better yet, it was the first pair of glasses with which I could see better than with contact lenses (as those don’t have a cylinder).

For all the skepticism at others (eye professionals at that), did he checked his enthusiasm for placebo effect? Or the IKEA effect for that matter?

The guy seems eccentric in a creative way, but unbearable...

Re: Making My Own Glasses

#32

Post by nickjj » Fri, Oct 04, 2019, 1:11 PM UTC

As a life long glasses wearer I don't really agree there's a problem with the "better or worse" method. It's a pretty interesting implementation of bisection search and it's a very controlled environment. It's also a great example of how constraints (time) helps you arrive at a good answer without over thinking it.

If you were out wandering the streets or looking at random things with no constraints you would be overwhelmed with choice and it would be very hard to draw a conclusion. You may decide what's right is based on looking at something, only to find out after all of that something else 4 days later looks way off because you didn't see that during your real world test. You end up being individually burdened with making the decision instead of letting science do its thing.

The only issue I have is frames because it's very possible to get frames that are comfortable for the few minutes you try them on in the store but they end up being horrendously uncomfortable after a day or few days of usage (even after many adjustments).

I don't know how to solve that problem though because in order to wear the frames for a long test period you would need to be able to see, which means your real lenses need to be placed inside.

Re: Making My Own Glasses

#33

Post by cameronh90 » Fri, Oct 04, 2019, 1:12 PM UTC

alfonsodev wrote: post #2

> Optician: “Now with this lens, do you see better or worse?” > O: “Honestly, I have no clue. Maybe. Maybe not? The letters look similar but different.” [edit] Reprahsing to make it clearer: will it be possible in the future to measure objectively?

Sort of. There's a device called an autorefractor which can get a pretty good estimate out of your refractive error. However traditional eyesight tests tend to provide better results.

I believe wavefront guided LASIK uses some kind of automatic method of determining refractive error called an aberrometer. Some ophthalmologists have a device called an i-profiler that they use as part of their assessment which appears to be an aberrometer.

Everything I've read on the matter seems to me to indicate that there is possibly some kind of hybrid automated autorefractor/aberrometer type technology that could be created to give fairly objective and accurate measurements of refractive error with no human operator, but given that legally an ophthalmologist would need to sign off the prescription anyway the upside is probably limited.

Re: Making My Own Glasses

#34

Post by gvb » Fri, Oct 04, 2019, 1:15 PM UTC

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 measurement to the glasses information. When I put on the resulting glasses, I don't have any eye strain symptoms and my vision is good (instantly).

When I went to cheap storefront glasses places (I don't do that any more) and I put on the resulting glasses, I get a "stress" signal from my eyes and then they adjust to work with the suboptimal glasses but the eye strain is always there.

Re: Making My Own Glasses

#35

Post by pacaro » Fri, Oct 04, 2019, 1:21 PM UTC

css wrote: post #26

umvi wrote: post #23

> and she’s not happy to share the measurements with me as she fears I’ll run off and get my glasses made online I hate this! Are they really allowed to do this? "What's my prescription?" "Not telling"

They are most certainly not allowed to withhold it: https://www.ftc.gov/tips-advice/business-center/guidance/com...

TFA is most likely set in Germany, where different rules apply

Re: Making My Own Glasses

#36

Post by hrktb » Fri, Oct 04, 2019, 1:26 PM UTC

chooseaname wrote: post #10

> As a doctor I know some things about the human eye so I understand how to use those lenses. However, I have no clue about the magic ritual of the optician (“Do you see better with this lens?” - selects random lens and holds it in front of my eye). >Luckily, I didn’t have to. There's a specific reason why they do this and ask you to make a decision in an instant. It's called accommodation. Your eyes will quickly try…

> There's a specific reason why they do this and ask you to make a decision in an instant. It's called accommodation.

You are right. It can be an issue in the other direction though.

People are checked after often sizeable waits looking at the same thing (their phone, the wall, outside) for a long time.

When you then start the switching lens tests, there will be a set of lens optimal for your current situation, and a different set of lens that would fit better for a long day of doing whatever you are usually doing with the glasses on.

Knowing how good a pair matches after accommodation is equally valuable, IMO.

Re: Making My Own Glasses

#37

Post by ThePadawan » Fri, Oct 04, 2019, 1:29 PM UTC

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 actually read up on the local legalese around this (for Switzerland), and it turns out that doctors can refuse to share information with the patient if they consider it unhelpful/dangerous to do so, but have to share it with other medical staff should they request it.

Especially in the context of psychotherapy or when using placebos, this makes a lot of sense.

Re: Making My Own Glasses

#38

Post by fbr » Fri, Oct 04, 2019, 1:32 PM UTC

chooseaname wrote: post #10

> As a doctor I know some things about the human eye so I understand how to use those lenses. However, I have no clue about the magic ritual of the optician (“Do you see better with this lens?” - selects random lens and holds it in front of my eye). >Luckily, I didn’t have to. There's a specific reason why they do this and ask you to make a decision in an instant. It's called accommodation. Your eyes will quickly try…

> There's a specific reason why they do this and ask you to make a decision in an instant. It's called accommodation. Your eyes will quickly try and accommodate and find focus if they're allowed to stare too long. This could explain the reason he got such different results from the exams. He was trying too hard. Just follow directions.

I don't have a long experience with glasses but I have never received these instructions and my experience is similar to the author.

Re: Making My Own Glasses

#39

Post by gowld » Fri, Oct 04, 2019, 1:34 PM UTC

hrktb wrote: post #36

chooseaname wrote: post #10

> As a doctor I know some things about the human eye so I understand how to use those lenses. However, I have no clue about the magic ritual of the optician (“Do you see better with this lens?” - selects random lens and holds it in front of my eye). >Luckily, I didn’t have to. There's a specific reason why they do this and ask you to make a decision in an instant. It's called accommodation. Your eyes will quickly try…

> There's a specific reason why they do this and ask you to make a decision in an instant. It's called accommodation. You are right. It can be an issue in the other direction though. People are checked after often sizeable waits looking at the same thing (their phone, the wall, outside) for a long time. When you then start the switching lens tests, there will be a set of lens optimal for your current situation, and a…

It's important to only do eye tests when you are tired, so you get lenses that help you when you need them.

Re: Making My Own Glasses

#40

Post by kmm » Fri, Oct 04, 2019, 1:35 PM UTC

He probably saw the first result incorrectly, opticians almost exclusively use negative cylinders, it seems incredibly unlikely that he would both stumble upon a rare exception using positive cylinders, and that she'd coincidentally get his astigmatism way wrong as well.

I share his, uhm, perfectionism regarding optical corrections, and it's led to quite some anxiety. I feel like eye exams here aren't done with a lot of care, and that they just aim for "good enough". I'm not sure what to do with the knowledge that you can buy such an optician kit and test yourself. It's either a great or an absolutely terrible idea.