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Comment by Animats | Hacker News Reader

Here's a useful program someone in the HN/YC universe could write - something that uses your computer or phone camera to measure your interpupillary distance. This is a bit tricky to do yourself with a ruler and a mirror.

Just have the user take a selfie while holding some object of known dimensions on their forehead. Like a dollar bill. Find the eyes and pupils (OpenCV can do that), find the reference object, calculate.

Then take a picture of the prescription, OCR to the numbers (which will need a really good OCR program given the handwriting of many ophthalmologists), confirm the data with the user, and take the order for new glasses. Composite a selfie with pictures of glasses so you can see them on your face.

Order from China, deliver via E-Packet, profit. Who needs Luxotica?

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Some of these apps exist, but none are as accurate as a ruler and two post-it notes with a pinhole.

If Apple opens up the depth sensor on the iPhone camera, such apps will be more accurate.

The trouble with do it yourself measurement of the distance between eyes is that it's done with eyes that need glasses, without wearing them. You need a second person or hardware.

In my case, my distance vision is bad, but a meter away is sharp without correction. In fact, I’ve never had a prescription that doesn’t f-up my near vision, so I had to do the measurement without glasses on.

I do it while wearing my contacts :)

> something that uses your computer or phone camera to measure your interpupillary distance

Presumably any program that does face recognition already has this capability somewhere inside it, and you just need to either extract it out (if FOSS) or trick the engine into doing just that one thing for you.

The Warby Parker App already does a much better version of this. Open the front facing camera and any frame you want is super imposed in real time on your face. It works very well, on a newer iphone at least. You do have to enter your prescription details by hand though.

The other useful program would be one that can process a photo of a person wearing glasses and suggest which adjustments they should make to get the frames seated properly. Bonus points if the program can also spit out the script details based on the observed distortion of one's face through the lenses.

I was very happy with my online order (Zenni), but it took a bit of mucking about to get them adjusted properly and sitting comfortably on my face.

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