Frequently Asked Questions/Glasses
(please read this!)
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- 1 Buying glasses
- 2 How do I measure my PD? (pupillary distance)
- 3 Why are my glasses giving me a headache?
- 4 Test lens kits
- 5 Plus lenses
- 6 Diopters
- 7 Should I stop wearing glasses?
- 8 Contact lenses
- 9 How do I calculate math related to optics?
- 10 Can you get better than 20/20 vision?
- 11 Is it OK to use several different diopter glasses?
- 12 How do I reduce prescription complexity?
- 13 See also
Where should I buy glasses online?
See Category:Lens seller.
How do I measure pupillary distance?
Are polycarbonate lenses bad for your eyes?
The fact that they are polycarbonate makes no difference to your eyes.
Blog post: Polycarbonate Lenses – Bad For Your Eyes?
Why can't I purchase glasses without a prescription?
Because the industry doesn't want you to have control or understanding about anything that's happening to your eyes.
Blog post: Do. Not. Measure. Your. Eyesight.
How do I measure my PD? (pupillary distance)
Why are my glasses giving me a headache?
When myopia increases, people's headaches tend to get worse. This is largely due to the shrinking field of view higher diopter correction gives. There's a huge amount of variation in general in this area. It's safe to say though, the higher your diopters, the worse the headaches.
Test lens kits
Do I need a test lens kit?
No, generally you don't need a test lens kit. It may be helpful if your myopia is particularly complicated. Most people don't buy a test lens kit and do fine.
How do you use a test lens kit?
You insert the lenses from the kit into the really dorky-looking glasses. This way you can test different lenses and how they work.
You can find optometrist approved guides on how to use a test lens kit here.
Where can I buy an optometrist test lens kit?
How do plus lenses work?
Plus lenses make you more short-sighted, not less. They are for the most part useless when it comes to improving myopia.
Should I use plus lenses to improve eyesight?
What should I reduce to?
Is it ok to use several different diopter glasses?
Should I stop wearing glasses?
I have low myopia. Can I stop wearing my glasses?
If you have below 2 diopters of myopia, you can definitely look at not wearing glasses any more.
Blog post: Low Myopia: When Can I Stop Wearing Glasses?
Should I use glasses or contact lenses for close-up?
You can wear contact lenses with plus lenses to achieve the same effect as a pair of differentials. It's generally preferable to wear glasses in general, but people have managed to improve their eyesight with contact lenses.
See optics related math for more information.
Can you get better than 20/20 vision?
Is it OK to use several different diopter glasses?
How do I reduce prescription complexity?
From the blog: The Big Primer On Buying Lenses (And Cost!)