The large space toward the back of your eye between the lens and the retina is called vitreous space. It is filled with material, which has the consistency of a soft, clear jelly.
What is vitreous detachment?
The vitreous is tightly attached to the outer wall of the eye or the retina. With time the vitreous tends to shrink and pull away from the retina. This pulling away may be accompanied by the sensation of flashing lights or black spots. These black spots tend to move around and come and go. They are often called floaters. The technical term for these black spots is called vitreous detachment.
When the floaters first occur, especially when they are associated with flashed of light, there is a very small chance of a more serious problem occurring – that is, a retinal detachment. If you were to develop a retinal detachment, there would be a sudden, profound decrease in your vision, like a curtain coming down over the vision. However, the chances of a retinal detachment occurring are about 1 in 10,000.