What is the meaning of floaters?
Floaters are seen by the patients as floating black spots on their visual field.
Why patients see floaters
The eye consists of two segments, the anterior segment which lies infront of the lens and is filled with aqueous humor while the posterior segment is filled with vitreous humor. During childhood, the vitreous is clear and is jellylike material. Later in life, vitreous normally will undergo liquefaction and changed from jellylike material to fluid like material in a process called vitreous syneresis and this will cause the collage fibers within the vitreous to form strands. With each eye movements, those strands will also move, causing floaters.
Another normal mechanism of floaters is posterior vitreous detachments. Normally there are adhesions between the vitreous and the retina and for some reasons like old ages, myopia and trauma; these adhesions will be released causing vitreous detachments from the retina. Vitreous will collapse inside the posterior segment of the eye and with each eye movements, collapsed vitreous will move, causing floaters.
Posterior vitreous detachment is normally present in old ages and also in myopic patients. Usually it occurs without complications and only the patients will complain of floaters which usually will disappear from few weeks to month later. Sometimes, posterior vitreous detachment from the retina is incomplete, in which some parts will remain attached to the retina, causing traction on the retina. This traction will be noticed by the patient as flashes of lights and with time, this traction can lead to retinal detachment.
Note: Any patient who noticed floaters for the first time should have complete ocular examination to rule out any incomplete vitreous detachments with traction on the retina.
Other causes of floaters are deposits on the vitreous humor which can occur after uveitis in which white blood cells will deposit, after resolved vitreous haemorrhage in which red blood cells will deposit, after cataract surgery especially when there is posterior capsule rupture, after intraocular injections in which drug remnants will deposit in the vitreous.
What are the causes of deposits in the vitreous humor?
1- Causes of uveitis like sarcoidosis, multiple sclerosis, Behçet diseases, leukemia and many other causes of intra-ocular inflammation
2- Causes of intra-ocular infections like syphilis, toxoplasmosis, tuberculosis and CMV retinitis
3- After cataract surgery especially with posterior capsule rupture
4- After YAG laser capsulotomy, in which the laser will be used to create a hole in fibrosed posterior capsule.
How floaters disappear?
1- By brain adaptation, in which your brain will ignore the presence of these floaters and you will no long see them
2- By natural absorption process of the eye, especially of cases that occur after uveitis, vitreous hemorrhage.
3- Treatment of the underlying conditions like with anti-inflammation and antibiotics
4- Vitrectomy, which is the surgery to remove the vitreous. It is indicated when there are large amounts of deposits in the vitreous that did not cleared with time or medications and they affect the vision of the patient.