Eye Floaters and Flashes, Animation.

From the patient’s point of view, floaters
are objects that drift around in the field of vision. They may look like blobs, little worms or
cobwebs that move with the eye’s movement. They seem impossible to focus on and are most
visible when looking against a bright plain background such as a blue sky or a blank computer
screen. Floaters are in fact particles suspended inside
the vitreous body – the gel-like structure that fills the space between the lens and
the retina. What we see, however, are not the floaters
themselves, but the shadows they cast on the retina. The closer they are to the retina, the larger
and clearer they appear in the field of vision. Commonly, floaters develop as part of normal
aging. With age, the gel-like vitreous body undergoes
syneresis – a process in which water is separated from solid components, creating
pockets of fluid that are perceived by the patient as blobs or little worms. The major structural protein of the vitreous
– collagen fibrils – become denatured, clump together and can be seen as floating
strings or cobwebs. The fluid pockets may collapse, causing the
vitreous to shrink and pull away from the retina. This pulling exerts mechanical stimulations
on the retina, producing “flashes of light” or photopsias in peripheral vision. Eventually, the vitreous is separated from
the retina. This is known as posterior vitreous detachment
or PVD. PVD is very common but is generally benign
and does not require treatment. The floaters may be a nuisance to vision,
but in most people, the brain will eventually learn to ignore them. Complications may happen, however, in a small
number of cases. As the vitreous detaches, it may pull the
retina with it, resulting in a retinal tear. Fluid from the vitreous may then sip through
the tear and cause the retina to separate from the underlying tissue. This is known as retinal detachment and is
a sight-threatening condition. Worrying signs to watch out for include:
– A sudden increase in number of new floaters, especially tiny ones as these may represent
pigments or blood cells released from the damaged retina or blood vessels. – A shade or curtain of vision – a sign
of loss of vision from the detached part of the retina. People with high degree of myopia are at higher
risks of having PVD. The longer shape of the eyeball in myopia
increases the likelihood of PVD and also the risk of retinal complications. This is because the retina is stretched over
a larger surface and becomes thinner and more vulnerable to tears. Other risk factors for PVD include intraocular
inflammation, trauma, previous eye surgery, diabetes and family history.

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