The retina is a light-sensitive layer of tissue that lines the inner surface of the eye. The retina is attached to the vitreous, which is a gel-like substance that composes most of the volume of the eye. As a result of the aging process, the consistency of the vitreous changes and becomes thinner. This can change the shape of the vitreous causing it to pull away from the retina creating a tear. Without treatment, a retinal tear will cause a retinal detachment.