# If there are drops that dialate eyes why aren't there drops to undialate them? **URL:** \ **Category:** Factual Questions\ **Created:** [April 19, 2007, 9:05pm UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848 "2007-04-19T21:05:43Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![R.P.McMurphy](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@R.P.McMurphy](https://boards.straightdope.com/u/R.P.McMurphy)\ **Post date:** [April 19, 2007, 9:05pm UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/1 "2007-04-19T21:05:43Z")
To do a thorough examination of the eyes they dialate them with drops. After about 20 minutes the eyes are fully dialated. Then they send you out to endure several hours of poor vision and misery. Why isn’t there an eyedrop that will reverse the process and get you back to normal, say within an hour? ---
**Author:** ![pinkfreud](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pinkfreud/32/17603_2.png) [@pinkfreud](https://boards.straightdope.com/u/pinkfreud)\ **Post date:** [April 19, 2007, 9:14pm UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/2 "2007-04-19T21:14:13Z")
There are drops which reverse dilation. One brand is [Rev-Eyes](http://www.drugs.com/cons/rev-eyes-ophthalmic.html). ---
**Author:** ![R.P.McMurphy](https://avatars.discourse-cdn.com/v4/letter/r/7993a0/32.png) [@R.P.McMurphy](https://boards.straightdope.com/u/R.P.McMurphy)\ **Post date:** [April 19, 2007, 9:27pm UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/3 "2007-04-19T21:27:40Z")
[QUOTE=pinkfreud] There are drops which reverse dilation. One brand is [Rev-Eyes](http://www.drugs.com/cons/rev-eyes-ophthalmic.html). [/QUOTE] Then why don’t the eye doctors administer them. ---
**Author:** ![pinkfreud](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pinkfreud/32/17603_2.png) [@pinkfreud](https://boards.straightdope.com/u/pinkfreud)\ **Post date:** [April 19, 2007, 10:04pm UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/4 "2007-04-19T22:04:55Z")
[QUOTE=Spartydog] Then why don’t the eye doctors administer them. [/QUOTE] Some do. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [April 19, 2007, 10:09pm UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/5 "2007-04-19T22:09:21Z")
I asked this very question and was told that, yes, they could undilate my eyes but that I wouldn’t like the side effects. I don’t remember what they all were but one of them was beet red eyes for a few days. I declined. ---
**Author:** ![robardin](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@robardin](https://boards.straightdope.com/u/robardin)\ **Post date:** [April 19, 2007, 10:13pm UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/6 "2007-04-19T22:13:58Z")
[QUOTE=Ring] I asked this very question and was told that, yes, they could undilate my eyes but that I wouldn’t like the side effects. I don’t remember what they all were but one of them was beet red eyes for a few days. I declined. [/QUOTE] Just speculating, but imagine the likely results of an overdose… Eeek! ---
**Author:** ![ouryL](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ouryl/32/6067_2.png) [@ouryL](https://boards.straightdope.com/u/ouryL)\ **Post date:** [April 19, 2007, 11:11pm UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/7 "2007-04-19T23:11:42Z")
Night blindness, I would guess ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [April 20, 2007, 12:27am UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/8 "2007-04-20T00:27:31Z")
I work in an ophthalmology department, and we don’t administer any undilating drops. When the topic came up, one physician said that the kind he was familiar with only decreased the dilation time by an average of 20 minutes, and that’s pretty tiny compared with how long some people stay dilated. Me, I tend to have noticeably large pupils for 6 or more hours after dilation. Checking the side effects, I would also assume that they’re not terribly acceptable risks considering that you can just undilate naturally. ---
**Author:** ![NinjaChick](https://avatars.discourse-cdn.com/v4/letter/n/71c47a/32.png) [@NinjaChick](https://boards.straightdope.com/u/NinjaChick)\ **Post date:** [April 20, 2007, 1:06am UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/9 "2007-04-20T01:06:25Z")
Huh. I’d been lead to believe that there wasn’t an ‘antidote’ because the drops worked more or less topically, so unless you washed out your eyes, you just had to wait. Granted, the ophthalmologist who told me that was less than truthful about any number of things, so…learn something new every day. ---
**Author:** ![xiix](https://avatars.discourse-cdn.com/v4/letter/x/d6d6ee/32.png) [@xiix](https://boards.straightdope.com/u/xiix)\ **Post date:** [April 20, 2007, 2:13am UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/10 "2007-04-20T02:13:33Z")
good ol’fashioned heroin would do the trick. [cite](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=760755&dopt=Abstract) ---
**Author:** ![Chief\_Pedant](https://avatars.discourse-cdn.com/v4/letter/c/a6a055/32.png) [@Chief\_Pedant](https://boards.straightdope.com/u/Chief_Pedant)\ **Post date:** [April 20, 2007, 3:20am UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/11 "2007-04-20T03:20:38Z")
[QUOTE=Spartydog] To do a thorough examination of the eyes they dialate them with drops. After about 20 minutes the eyes are fully dialated. Then they send you out to endure several hours of poor vision and misery. Why isn’t there an eyedrop that will reverse the process and get you back to normal, say within an hour? [/QUOTE] There are drops to make the pupil smaller (miosis) and drops to make it larger(mydriasis). They do not work in tandem as if one were an effector and the other a reverser, as it were. I have no idea what the net effect of atropine (dilation) and pilocarpine (constriction) would be, as examples. We are usually going for one effect or the other. While different types of drops have different mechanisms and different durations, we usually just let the effect wear off. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [April 20, 2007, 3:53am UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/12 "2007-04-20T03:53:57Z")
Side question for the med experts in the thread: How does one pronounce [Cyclomydril](http://home.intekom.com/pharm/alcon/cyclomyd.html)? My baby had a life-threatening vagal reaction to it twice (tachy and then brachycardia with apnea), and I’ve forgotten how to say it so doctors don’t give it to her again. sigh-CLA-mah-drill? sigh-clowe-MY-drill? Something like that? I have it written down just in case and it’s in huge warning letters all over her chart and the folder it comes in at her current eye doctors, but the last time I said it aloud I got funny looks and I’d rather get it right. And is it ever used for anything other than dilating pupils? ---
**Author:** ![Rigamarole](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)\ **Post date:** [April 20, 2007, 6:20am UTC](https://boards.straightdope.com/t/if-there-are-drops-that-dialate-eyes-why-arent-there-drops-to-undialate-them/400848/13 "2007-04-20T06:20:02Z")
Just put sand in them. Make sure they are the Sands of Time, though - other types of sand may irritate your eyes.