You stop by @endmyopia, read the blog.  You wear your regular glasses, from the friendly optic shop.  You read about rampant overprescription.  What, you think, are they talking about?  I’m not overprescribed.  My glasses are just right!  I can see fine, so what’s all this fretting about?

If you’re that guy, wondering, I’ll show you exactly what the fretting is about.  Take a quick read at Tim’ form post, here:


Wow.  Just … wow.

Above isn’t because Jake waved his magic camel over the proceedings, and reduced Tim’s prescription by 1.5 diopters (and 1.25, and diopter ratio, and astigmatism … wow).  I’m not saying I don’t have a magic camel or that I don’t wave it occasionally, over various proceedings.  All I’m saying is, this one wasn’t me.

Just look at that prescription change!  He goes from a -8.00 to a -6.50, and can still see 20/15 in decent light.  From a -6.50 to a -5.25.  20/15.  He drops his astigmatism by a quarter diopter.  20/15.  

20/30 is considered adequate vision for driving.  20/15 is I-see-ants-from-space vision.  Here, eye chart size representation for reference:

That’s positively tiny.

Ok, so 20/15 isn’t ants-from-space vision.  But it’s quite a bit beyond adequate, and quite a bit better than 20/20.  

Can you reduce your prescription by a diopter and a half, monkey with diopter ratio, and for good and gratuitous measure also cut your astigmatism correction, and expect to still have 20/15 vision?  Really, can you?  Should you?  

They prescribe you glasses as high as you can possibly take.  And if you ask them, hey, what does “hyperopic defocus” mean, anyway?  They’ll stare at you blankly, and tell you that you can pick up your new glasses tomorrow.  

Housekeeping:  Return of the Jedi later on today.  Or just return of Jake to home base, the Hong Kong trip is concluded.  So as of tomorrow things will be back in relative order (e-mail backlog and incrementally buggier forum signatures).