From what I can figure, Naphcon-A is just another name for Visine. The two active ingredients - naphthazoline HCl (a 'redness reliever' that relieves swelling in ocular blood vessels) and clorpheniramine maleate (an antihistamine that reduces mucous buildup and swelling - will reduce redness of the eyes, but I can't see why they would affect pupil size.
Basically to the best of my understanding, Naphcon-A or Visine-A will be good for "stoner redeye" but not much help for "pillhead 20c pupils".
On the other hand there are glaucoma medications called miotics (as mentioned above by SD) which come as eyedrops (including - Ocusert, Akarpine, E-Pilo, Isopto Carpine, Pilocar, Pilopine, Pilostat) which are used to increases drainage of intraocular fluid. Many people who use these medications complain of dim vision, especially at night, due to constriction of the pupil. Miotics increase drainage of intraocular fluid by making the pupil size smaller and thereby increasing the flow of intraocular fluid from the eye.
I don't know whether these would be easy to obtain, or safe to use as pupil constrictors for post-mdma use, however.
BigTrancer
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Load universe into cannon. Aim at brain. Shoot.
[This message has been edited by BigTrancer (edited 25 September 2001).]