Have you ever seen a tiny worm or dots or circles or lines or cobwebs in your field of vision. If you move your eye to try to look at that it will move away in the direction you move your eye. Their shapes vary greatly, but will often appear as spots, cobwebs, or randomly shaped stringy objects. These can be semi-transparent or dark and appear to float in front of your vision.
What you are seeing is a common phenomenon known as floaters. The scientific name for these objects are Muscae Volitantes, a Latin word for flying flies. They are not worms or external objects at all. While they seem to be in front of your eye, but actually they exist inside your eyeball. Floaters may seems alive since they move and change shape but they are not alive. Since they are within the eye, floaters move as the eyes move. They seem to float across your vision in the distance, especially looking at something plain, like a blank wall or a blue sky.
To better understand about floaters, we need to know how our eye works.
Light rays enter the eye through the cornea, the clear front “window” of the eye. The cornea’s refractive power bends the light rays in such a way that they pass freely through the opening in the center of the iris through which light enters the eye.The iris works like a shutter in a camera. It has the ability to enlarge and shrink, depending on how much light is entering the eye.
After passing through the iris, the light rays pass through the eye’s natural crystalline lens. This clear, flexible structure works like the lens in a camera, shortening and lengthening its width in order to focus light rays properly.
Then the light rays pass through a dense, transparent gel-like substance, called the vitreous that fills the eyeball and helps the eye hold its spherical shape.
Finally the light rays come to a sharp focusing point on the retina. The retina functions much like the film in a camera. Retina captures all the light rays. Photosensitive cells called rods and cones in the retina convert incident light energy into a neural ‘image’ that it then transmits to the brain through million of nerve fibers called the optic nerve.
So, when a beam of light enters the eye, it passes through accessory structures – such as the cornea, iris, lens and vitreous – finally to reach the photosensitive retinal layer.
How floaters formed?
The vitreous humor, or often just “vitreous”, is a clear gel that fills the gap between your retina and lens, helping maintain the round shape of your eye in the process. This gel is about 99% water and 1% other elements; the latter of which consists mostly of a network of hyaluronic acid and collagen.
As you age the gel like substance in Vitreous starts to thicken or shrink. As the vitreous shrinks, it becomes somewhat stringy. When light rays passes through Vitreous, this stringy elements creates shadow on you retina. This shadow is actually what you are seeing when you see the eye floaters.
In most cases, floaters are part of the natural aging process. Floaters can also be caused by small flecks of proteins or other material that were trapped in the Vitreous during eye formation.
They can be distracting at first, but eventually tend to “settle” at the bottom of the eye, becoming less bothersome. They usually settle below the line of sight and do not go away completely. If you have had these for years, your eye and your brain learn to ignore them. Sometimes the number of floaters increases as you get older. Some people find that floaters can be a nuisance, but most people become used to them. They rarely cause problems with your vision.
The reason the floating specs never seem to stay still is because floaters, being suspended in the vitreous humor, move when your eye moves. So as you try to look at them, they will appear to drift with your eye movement.
Everybody’s eyes experience these sort of effects but the number and type vary. Generally they often go unnoticed. However abnormally numerous or large number of floaters that interfere the vision may be a sign of more serious condition requiring immediate medical treatment.