Cobwebs, specks, worms, squiggles, flies, “I thought I saw a rat run across the kitchen floor but when I looked it wasn’t there” – eye floaters can take on all sorts of shapes and (evidently zoomorphic) forms. They can vary from an elusive drifting spot noticeable only against a clear, blue sky to an irritating blob in the center of your vision, determined to block out the next word of every sentence you try to read.

Most Eye Floaters Are Harmless
In most cases, eye floaters are harmless, a natural by-product of an aging eye. Inside the eyeball there is a transparent gel known as the vitreous humor, which sits between the lens and the retina and takes up about 80% of the eyeball’s space. At birth, the collagen fibrils and other components making up the vitreous are orderly and structured but after the first decade of life, this gel begins to liquify and lose its organization. By about 70 years of age this liquefaction is complete, and the vitreous humor has undergone what is known as a posterior vitreous detachment (PVD). During the liquefaction process, the vitreous forms both fluid-filled cavities as well as little gel blobs or stringy clumps of collagen that are no longer optically transparent. These spots and lines are what you see as eye floaters and what made your mom swat at that invisible fly. An eye PVD occurs as the vitreous liquefies and shrinks, pulling away from its adhesions at various sites on the retina. As this happens, some people may notice a flashing light in the periphery of their vision, similar to a lightning strike (minus the actual lightning). This phenomenon occurs because the tugging of the liquifying vitreous gel against its adhesion point to the retina stimulates the sensation of light.

 
But Eye Floaters Can Also Indicate More Serious Eye Problems
If one or several eye floaters suddenly appear in your vision, it is important to seek an eye doctor’s attention as you may have noticed the preceding paragraph began with “in most cases”. In other cases, the presence of an eye floater can herald a much more serious ocular problem. While floaters and flashes can indicate a normal age-related PVD in your eye, they can also present during a retinal tear or detachment. In fact, the pulling of the vitreous gel from the retina during a PVD can cause a retinal tear in about 14% of cases. The retina is a thin layer lining the inside of the eyeball and imperative to vision is the condition that this retina remains attached to the inside of the eyeball. If the retina were to develop a tear or part of it peel away entirely from the rest of the eye, the composition of the resulting floaters may be more from free-floating blood or particles of torn retinal tissue drifting around the vitreous rather than the benign flies and squiggles from a PVD. Another symptom of a retinal detachment is the perception of a shadow or curtain falling across the vision but this does not always occur, depending on the location of the detachment. As there’s no other way to differentiate a harmless eye PVD to a painless about-to-lose-your-vision retinal detachment without a thorough examination of the retina by an eye doctor, it’s a good idea to always get checked out should an unexpected floater (or floaters) pop up.

Eye floaters from blood and hemorrhaging in the vitreous can also arise from other eye problems, including diabetic eye disease or trauma to the eye. Another cause of sinister floaters is from some sort of inflammation of the vitreous, known as vitritis, with these floaters usually being comprised of white blood cells and other components of the immune response. Vitritis can occur due to several reasons, including viral, bacterial, or fungal eye infections, and typically also presents with pain. A very rare cause of floaters can come from tumors inside the eyeball.

 
Eye Floaters Treatment
But enough about eye cancer. We would rather talk about flies and worms and rats! So, what can be done about these pests? Unfortunately, unlike the living animate counterparts, eye floaters are not always as simple or convenient to get rid of. In majority of cases, as floaters from PVD are considered quite normal and benign, they’re typically left alone. Over time they tend to settle due to gravity and become less noticeable; the brain also tends to desensitize to their presence. Sometimes an eye floater can be really quite annoying, such as the one that obscures words as you try to read a riveting novel. In the past, a vitrectomy – an invasive surgical procedure involving scooping out the entire vitreous and all the little pests within it – was the only option and was not often recommended due to the risks associated with such an invasive procedure. Nowadays, another option exists with the use of a laser. Laser vitreolysis aims to break up large floaters into smaller, less obtrusive spots or in some cases, vaporize them completely. Unfortunately, not all floaters are suitable for this treatment, depending on their size and location.

So, there you have it, from cobwebs to lightning, the inside scoop on floaters inside the eye.

 
References
Vitreous: the next frontier. http://retinatoday.com/2016/06/vitreous-the-next-frontier/
Facts about floaters. https://nei.nih.gov/health/floaters/floaters
Flashes and floaters. https://www.racgp.org.au/afp/2014/april/flashes-and-floaters/
Floaters. https://www.msdmanuals.com/professional/eye-disorders/symptoms-of-ophthalmologic-disorders/floaters
Eye floaters, flashes and spots. https://www.allaboutvision.com/conditions/spotsfloats.htm