The posterior 2/3 of the eye is filled with a jelly like substance called the vitreous.
With age the collagen matrix that holds the gel in place degenerates, turning the vitreous from a solid jelly into a mélange of pocket of water and collagen strands. If enough collagen is lost the vitreous can collapse acutely, causing what is referred to as a posterior vitreous detachment.
All these changes can cause FLOATERS. Floaters can cause visual disturbances, appearing as a circle, semi-circle, glob, spider web, cob web, strands or just as a vague film covering the vision.
Typically these changes dissipate with time as the floater relocates from one part of the vitreous to another. However there are patients where the floater is visually troubling. In these situations, laser vitreolysis is offered.