When does the iris dilate?

Question

When does the iris dilate?

Answer 1

your pupils will dilate when

1. you're scared (adrenalin/epinephrine release causes this, so you can see better for fighting or running away)

2. When you're attracted to someone, or when you even like someone, to see them better, also you could be a little nervous/scared. (but it also happens when you look at babies because you wanna see them well to protect them

3. in the dark to see better

Answer 2

The pupil dilates to block out or allow in sunlight. It's protecting the sensitive nerves when it gets smaller and it's soaking up all available light when it gets bigger, so the person owning said iris can see better.

Answer 3

Your iris doesn't dilate, it's your pupil that dilates, and it does so when it's dark and needs to let more light in to see.

Answer 4

Verse 1

And I'd give up forever to touch you

Cause I know that you feel me somehow

You're the closest to heaven that I'll ever be

And I don't want to go home right now

Verse 2

And all I can taste is this moment

And all I can breathe is your life

Cause sooner or later it's over

I just don't want to miss you tonight

Chorus

And I don't want the world to see me

Cause I don't think that they'd understand

When everything's made to be broken

I just want you to know who I am

Verse 3

And you can't fight the tears that ain't coming

Or the moment of truth in your lies

When everything seems like the movies

Yeah you bleed just to know your alive

Chorus

And I don't want the world to see me

Cause I don't think that they'd understand

When everything's made to be broken

I just want you to know who I am

Chorus

I don't want the world to see me

Cause I don't think that they'd understand

When everything's made to be broken

I just want you to know who I am

I just want you to know who I am

I just want you to know who I am

I just want you to know who I am

I just want you to know who I am  

Answer 5

When in dim light or darkness. Iris will dilate as a response to light receptors in the eye ball. The dilation occurs so as to allow more light to enter the eye in dim lighting conditions to allow a better image.

Iris also dilate when one is lying or getting excited. Increase of blood flow and adrenaline cause the iris muscles to contract and hence dilate.  

Answer 6

I dont think the iris does dialte. I know the pupil does which is the black round part of your eye in the center of the iris and that can be for a few reasons. i know they can dilate when your in the extremes of stress, exhaustion, and with exhaustion they will usually twitch or shake or when your under the influence of a narcotic. meth, speed, heroin, x, acid, etc...hope this helps.

Answer 7

The iris doesn't dilate--it's the ring of muscle around the pupil that controls the size of the pupil--so the PUPIL dilates, being opened by the iris (to be technically correct).

The pupil dilates in dark conditions to let more light in.  It takes about 20 minutes for your pupils to fully dilate in complete darkness, and that's when you're at your maximum sensitivity to light.

It can also dilate in response to certain medications, like stuff you'd get in your eye at the eye doctor, or belladonna, which was used to make women's pupils appear larger and thus more attractive.