Dark spots in vision are changes in a visual field which can be reported by patients. They are a consequence of the presence of floaters.
Floaters are deposits that may vary in size, shape and consistency. They also have different refractive index and may or may not be mobile. In some cases floaters are congenital and in others they are acquired. The acquired floaters are in majority of cases associated with degenerative changes in the vitreous humor or retina. The perception of floaters is medically known as myodesopsia. They interfere in normal vision due to the shadows they create and cast on the retina. Even a change in refraction when the light goes through a floater makes changes in one's vision. People usually describe floaters as spots, threads or fragments of cobwebs which flow slowly in the visual field.
Common Causes of Dark Spots in Vision
Certain physiological states as well as some illnesses may contribute to the occurrence of dark spots in vision.
The first thing associated with dark spots in vision is the process of aging. Due to this process the vitreous humor, which fills the inside of the eye and is normally transparent, starts to deteriorate. The process of deterioration is accompanied by the formation of protein-strands. The strands tend to group in clusters and if the clusters get in a way between the lens and retina a person sees dark spots. Apart from the process of aging, dark spots can develop as a consequence of an eye infection. In the infection the vitreous humor is infiltrated with lymphocytes, a debris made of infective agents and cells in charge with battle against these culprits may remain suspended in the vitreous and cause dark spots in vision.
One more common cause of dark spots in vision is posterior vitreous detachment. This condition develops as a consequence of deterioration of the vitreous, loss of its consistency and it's shrinking. All the previously mentioned leads to separation of certain parts of the retina, retinal tear or retinal detachment. The effects are in a form of dark spots in vision.
Additional Causes of Dark Spots in Vision
In some cases dark spots in vision may be a side effect of certain surgeries such as YAG laser surgery (a surgical procedure performed in patients suffering from cataract). People suffering from nearsightedness are more susceptible to the formation of debris in the eye, hence they are prone to dark spots in vision. This particularly refers to patients older than 50.