What chemical is in the eyedrops they use to dilate your eyes at the eye doctor?

Question

I'm just curious because I had it done for the first time today and it made me throw up and I almost fainted.

Answer 1

1.) Tropicamide ophthalmic may cause blurred vision, or make your eyes very sensitive to light. Be careful if you drive, operate machinery, or do anything else that requires you to see clearly. These effects can last for up to 24 hours

2.) Cyclopentolate ophthalmic may also make your eyes more sensitive to light. Until the effects wear off, protect your eyes from the sun or bright light

Answer 2

There are a few.  Mydriacyl, Cyclogyl, Neosenephrine.  and many more.

Answer 3

The iris has two basic sets of muscles. The sphincter runs around the opening. When it is stimulated, the pupil gets small. When light hits the eye, the retina picks up the light, and sends a message to the brain. A portion of the message gets diverted to the third nucleus to the pupillomotor portion that goes to both pupil sphincters. That causes the pupil to get smaller to ' limit' the amount of light going in. Drugs that block parasympathetic nerve impulses by occupying the receptor on the muscle, don't allow the sphincter to work, so the dilator muscle is unopposed and the pupil gets larger.

The sympathetic nervous system stimulates the dilator muscle of the iris which are radial fibers, like the spokes of a wheel.  When things that excite you do, things happen like the heart speeds up, blood pressure increases, breathing increases, hair goes up on the back of your neck, etc. AND the pupil dilates from the dilator muscle responding to all that adrenalin or nor epinephrine. An 'overdoes' of neosynephrine used to dilate, can cause your symptoms. When these drops are given in the 10% form (which they practically NEVER should be used), it can cause severe cardiodynamic responses. The 2.5% is usually enough for routine dilation.