Floaters, or spots, are particles that appear to drift in front of the field of vision. They are very common and are usually benign. A gel-like substance called the vitreous humor fills the inner part of the eyes. Floaters occur when parts of the vitreous break loose from attachment points on the retina. The actual floaters are not visible. The particles cast shadows on the retina causing the perception that a spot is in front of the eye.

Floaters usually look like small black or translucent specks. However, they come in all shapes and sizes, some being strand-like or resembling cobwebs. They are most noticeable when one is looking at a plain lighted background like a clear sky or a light colored computer screen. Flashes of light may accompany floaters. This indicates the vitreous is pulling on the retina. The flashes usually appear in the peripheral vision and may look arc or streak-like. They are most visible in a dark room or when the eyes make a rapid movement from side to side.

There are many causes of floaters. Some are present at birth. During fetal development some debris or protein can be trapped in the eye and is left suspended in the vitreous humor. Floaters also develop during the normal ageing process. When a person is born the vitreous has a gel-like consistency and it is attached to the retina in several places. As time goes on, the central part of the vitreous liquefies. When this happens the weaker center cannot support the heavier periphery and the vitreous collapses on itself. This collapse creates pulling on the retina resulting in the perception of flashes of light. The pulling also liberates retinal pigment producing floaters. Eventually the pulling usually results in the vitreous detaching from the retina. This is called a posterior vitreous detachment, or PVD. Once the vitreous detaches there is no longer pulling on the retina and the flashes stop. Certain eye diseases and injuries can also cause floaters.

Vitreous detachments are common and do not usually lead to permanent vision problems. However, on rare occasions when the vitreous detaches it can cause small tears or holes in the retina. When a tear occurs the liquified vitreous can then invade the opening and push the retina off the back of the eye. This is called a retinal detachment. When part of the retina detaches it can no longer get the oxygen and nutrients it needs to survive and vision loss can occur. A retinal detachment can be repaired surgically and vision can can be restored if it is treated soon after symptoms start.

If one experiences a sudden increase in floaters, flashes of light, or a curtain or veil coming over the vision he should see an eye doctor immediately to rule out a hole, tear or detachment of the retina. The doctor will dilate the pupils and use special instruments to examine vitreous, retina, and other internal structures of the eye.

Risk factors for retinal detachment include nearsightedness, age, diabetes, and cataract surgery. Regular eye examinations including dilation are recommended for these patients whether or not symptoms are present.

Dr. Jamie Barnes is an associate doctor at Bennett Optometry, with two offices in Ann Arbor. Contact her at bennettoptometry@gmail.com. Please visit our website http://www.bennettoptometry.com