What causes red eyes during crying?

I have been of late crying a lot. Before my leave I was crying 4-5 hours at work. And there didn’t ever seem to be a shortage of tears. My lacrimal glands were perfectly capable of pumping that amount right out. My eyes were getting pretty red and only partly responsive to Visine. I’ve already Googled for answers and checked the Wiki page on tears but no soap. The common answers that were useless Ansers.com and such were along the lines of, "Well, the tears wash away all the lubrication in your eye and thus your eye get irritated. Huh?

Wiki points out that different tears have different make-up but says nothing regarding any change in lubricative effect.

So what’s the Straight Dope? Why should my eyes get red when there being bathed in the very substance that supposed to keep them clear?

subconjunctival hemorrhage
Tiny capillaries carry blood through the white part of your eye are bursting. Visine is a vasoconstrictor.

So why are the capillaries bursting?

I have always assumed that eyes get red when crying because we tend to rub them. Is this wrong?

Well, in my case I’m not rubbing them. As to burst capillaries that sounds a little unlikely. Enlarged or dilated, sure. Anyway, the state of the symptom, redness, I’ve got. What I was really wondering about is still the cause.

Wiki had some info regarding different compositions of tears. It noted that

basal tears in this case being the normal tears generated by the lacrimal glands. Do any of those look like irritants? Maybe the cause is one of those.

I don’t know the answer to your GQ, but I may have found your soul mate.

This is just a WAG, but: Increased tears, means increaed blood flow (the water and other stuff in those tears has to come from somewhere), and it’s those enlarged blood vessels causing the red eye (that’s what blushing is, after all).

We can’t have the last word be a wild *** guess, so here’s a cite (discovered since posting) that backs up that guess and provides a bit more explanation: http://www.united-academics.org/magazine/lovehurts/why-do-my-eyes-get-puffy-and-red-after-crying/. Disclaimer: Never seen that particular site before today so I have no idea how reliable it is.

I also discovered a better explanation of the ‘tears wash the away lubrication’ answer you encountered in your own search. Emotional tears are more salty than the normal tears that lubricate your eyes. A saline solution (i.e. salt water) will draw water from, and release salt to, less salty areas around it (nature tends to seek a balance). This causes the normal film of water over your eyes to becomes more salty than the eyes it’s covering, and that same water-salt exchange happens again with your eyes.

It’s not the tears causing the redness, it’s the blood in the capillaries. Tears aren’t red. Blood is.