The vitreous body or vitreous humor or hyaline body is a transparent, gelatinous substance which fills the ocular cavity behind of the Cristallin.

Formed of 95% of Water, it gives to the eye its form and its consistency: it thus accounts for 90% of the volume of the eye. Its role is to guarantee the rigidity of the ocular sphere, and to maintain the Rétine places from there against the wall of the eye. The vitreous body constitutes one of the four diopters of the eye. Its index of refraction n=1,33

From its nature, it also absorbs most of the ultraviolet radiation; this protects to a certain extent the retina against the too violent exposures, but makes on the other hand not exploitable by the nervous system the sensitivity of the Rhodopsine, the photosensitive pigment of the eye, with this area of the spectrum.