While small in size, our eyes are constantly performing extremely intricate tasks in order to promote vision. The inside of the eye is filled with a clear substance called the vitreous humor, and the very back of the eye is referred to as the retina. The vitreous humor is completely attached to the retina through small, microscopic fibers made of collagen. The retina itself is a thin layer of light-sensitive tissue that lines the inner surface of the back of the eyeball and transmits visual signals to our brain through the optic nerve. Without a proper functioning retina, our brain would not be able to interpret any visual impulses, and thus, we would not be able to see. For visualization purposes, if you envision the eye as a small, inflated basketball, the air inside of the basketball would represent the vitreous humor, and the interior rubber lining of the basketball itself would represent the retina.
When we are born, the vitreous humor is more gel-like in appearance. As we age, however, it continuously liquefies into a more fluid-like solution, resembling the appearance of water. Over time, the vitreous humor naturally begins to separate from the retina, breaking apart the small microscopic connections that once attached the two together. This is referred to as a PVD, or posterior vitreous detachment. Once used as an adhesive to attach the vitreous humor to the retina, the collagen fibers are now floating around inside of the eye itself, creating the floaters that you see in your vision!
It is important to note that a PVD is common – it spontaneously happens to everyone as we age. You can think of it as a natural progression in the life cycle of the eye. Most often directly related to age, a PVD can also occur (though less commonly) as a result of trauma to the eye. While floaters are more frequently related to a PVD, they can also arise from other, more serious problems in the eye which is why it is important for any floaters – especially new ones! – to be examined by your retina specialist. As the vitreous jelly is separating from the retina, it can sometimes peel off with enough force and traction to pull on the very delicate retina, creating a retinal tear or detachment. These conditions require immediate medical attention and can cause severe vision loss if not treated in time.