Floaters and Photopsias
The human eye is like a hollow ball 4/5 of which is filled by a gel called vitreous. At a microscopic level the gel consists of a three-dimensional fibrillar skeleton surrounded by water.
As we age the vitreous starts to degenerate and loses its symmetrical three-dimensional form. This phenomenon is called syneresis of the vitreous and is perceived in the form of black irregularly shaped lines, which are more visible in brightly lit areas and high contrast and which follow the movement of the eyes. This situation may at times be annoying but does not cause permanent damage to the eye.
Floaters may also appear due to the detachment of the vitreous from the retina. These may be accompanied by flashes, as the vitreous that is detached pulls the retina. This could potentially be a rather dangerous condition, as the detachment of the vitreous could cause a tear on the retina, which requires immediate treatment.
Since it is difficult for patients to discern between the two conditions, they should visit an ophthalmologist when floaters appear.
Neither syneresis nor the detachment of the vitreous (if the retina is intact) require treatment. In rare occasions, if the symptoms are very annoying, they can be surgically removed.