I literally dropped one drop of Latisse in each eye thinking it was my contact solution. How bad is this?

Hello, luckily there shouldn't be much concern. This medication originally and still is used as an eye drop medication for Glaucoma. However, the one concern that is seen in patients is browning of the eyes. Just one drop shouldn't be a big concern.

I'm sorry to hear what happened.  The good news is your contacts probably provided some protection and Latisse shouldn't cause any problems if it comes in contact with the globe other than some mild irritation.  The active chemical in Latisse was initially used in eye drops to treat glaucoma.  I would suggest leaving your contacts out for a day and irrigating them out really well with saline or contact solution and you should be fine.  If the redness or burning persists then you should see an Ophthalmologist but I suspect you'll be fine in a day or two.  

I understand your concern. Before latisse was used to grow lashes, it was used as an eye drop for eye conditions.It can make the conjunctiva red and irritated. Take the contacts out and irrigate the eye with eye solution/ saline, Renu is a good brand.One episode is probably not a problem, but label your latisse more obviously so you don’t do it again.Best. Dr BrechtSeattle, Wa