# What does "50 \[square\] 17" mean on my glasses? **URL:** \ **Category:** Factual Questions\ **Created:** [August 3, 2011, 7:18am UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297 "2011-08-03T07:18:29Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Rachellelogram](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rachellelogram/32/8689_2.png) [@Rachellelogram](https://boards.straightdope.com/u/Rachellelogram)\ **Post date:** [August 3, 2011, 7:18am UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/1 "2011-08-03T07:18:29Z")
I was looking at my glasses today and saw some writing embossed on the right eye frame, right next to the nosepiece. I was wondering what it means? It’s two numbers, 50 then 17, with the shape of a square between them. Does it have something to do with measurements of the frame? [as an aside] On the earpiece it reads “TM CE NO BOUNDARIES WESTMINSTER BLK 140.” I assume this means the earpiece length is 140cm? And since I got them from Walmart and No Boundaries is a Walmart brand, that much is self-explanatory. I assume Westminster is the model and BLK the color. They’re black plastic frames, and I don’t see any other writing on them. I’m trying to size my current specs for ordering a new pair of glasses online and wondered if these numbers would be helpful or meaningful. ---
**Author:** ![Rachellelogram](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rachellelogram/32/8689_2.png) [@Rachellelogram](https://boards.straightdope.com/u/Rachellelogram)\ **Post date:** [August 3, 2011, 7:20am UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/2 "2011-08-03T07:20:18Z")
Oops, wrong forum. I meant to post this in GQ, reporting it myself for a change. Sorry! ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [August 3, 2011, 11:05am UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/3 "2011-08-03T11:05:58Z")
They’re dimensions of each lens – 50 mm wide, 17 mm tall. I suppose the optitian would need this information to pick frames for a particular prescription. Perhaps, say, bifocals are a bad idea on vertically short lenses? It must be useful in some other way but I don’t know off the top of my head. ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [August 3, 2011, 11:07am UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/4 "2011-08-03T11:07:54Z")
Moving thread from Great Debates to General Questions. ---
**Author:** ![Themenin](https://avatars.discourse-cdn.com/v4/letter/t/ee59a6/32.png) [@Themenin](https://boards.straightdope.com/u/Themenin)\ **Post date:** [August 3, 2011, 1:53pm UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/5 "2011-08-03T13:53:28Z")
The 17 refers to the “nose gap”. So your overall frame width is 117 mm : 2 times 50mm + 17mm. FWIW 17 is fairly wide. ---
**Author:** ![SCSimmons](https://avatars.discourse-cdn.com/v4/letter/s/e495f1/32.png) [@SCSimmons](https://boards.straightdope.com/u/SCSimmons)\ **Post date:** [August 3, 2011, 2:35pm UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/6 "2011-08-03T14:35:56Z")
> [@Themenin](#): > > The 17 refers to the “nose gap”. So your overall frame width is 117 mm : 2 times 50mm + 17mm. And the primary use the optician puts the numbers to is to place the optical center (OC) of the lenses correctly when they cut the lenses to the frames. The OC of each lens should be directly in front of the the pupil when you’re looking straight ahead; those frame measurements plus the measurement of the distance between your pupils (PD) gives the information needed to do this. (Former optician’s lab technician.) ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [August 3, 2011, 9:18pm UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/7 "2011-08-03T21:18:25Z")
> [@rachelellogram](#): > > I assume this means the earpiece length is 140cm? Sure, if you’re an Easter Island statue. ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [August 3, 2011, 9:54pm UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/8 "2011-08-03T21:54:45Z")
It means: “if you can read this, why do you need glasses?” ---
**Author:** ![kittenblue](https://avatars.discourse-cdn.com/v4/letter/k/ba8739/32.png) [@kittenblue](https://boards.straightdope.com/u/kittenblue)\ **Post date:** [August 3, 2011, 10:28pm UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/9 "2011-08-03T22:28:17Z")
I can’t read anything printed on my glasses without my glasses. Sigh. ---
**Author:** ![Rachellelogram](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rachellelogram/32/8689_2.png) [@Rachellelogram](https://boards.straightdope.com/u/Rachellelogram)\ **Post date:** [August 4, 2011, 12:46am UTC](https://boards.straightdope.com/t/what-does-50-square-17-mean-on-my-glasses/591297/10 "2011-08-04T00:46:34Z")
> [@Bryan\_Ekers](#): > > Sure, if you’re an Easter Island statue. Whoops, I meant mm of course. Sorry, the illogic of it doesn’t strike someone not used to the metric system XD