Here you go:
From Wikipedia:
The vitreous humor contains no blood vessels, and 98-99% of its volume is water (as opposed to only 75% in the cornea). In addition to water, the vitreous consists of salts, sugars, vitrosin (a type of collagen), a network of collagen type II fibrils with glycosaminoglycan, hyaluronan, opticin, and a wide array of proteins. Despite having little solid matter, the fluid is substantial enough to fill the eye and give it its spherical shape. The lens, on the other hand, is tightly packed with cells.[2] The vitreous humour has a viscosity two to four times that of water, giving it a gelatinous consistency.
It's practically jelly
Hunh. You must have one of those fancy internet gadgets I've heard so much talk about.
I wondered myself, but somehow it was one of the few things that's ever crossed my mind in the last decade or so where I got curious but didn't think to look it up.
But if I'm watching a movie and the actor playing the janitor looks vaguely familiar and I wonder where else I've seen him, I'm right on it!