vitreous humorListen to pronunciation(VIH-tree-us HYOO-mer)The clear jelly-like substance that fills the inside of the eyeball. As a person ages, the vitreous humor becomes more liquid.Enlarge this image in new windowAnatomy of the eye showing the outside and inside of the eye, including the eyelid, pupil, sclera, iris, cornea, lens, ciliary body, retina, choroid, optic nerve, and vitreous humor. Search NCI's Dictionary of Cancer TermsStarts withContainsBrowse:ABCDEFGHIJKLMNOPQRSTUVWXYZ#