What is Vitreous Floaters?
As part of the normal ageing process, the vitreous (a gel-like substance at the back of the eye) degenerates. This causes the formation of veils and clumps in the vitreous, which float in the section behind the lensThe lens fulfils the same role as the lens in a camera. It handles about one-third of the focusing power of the eye and is critical for good vision.See Info on Eyes – Anatomy. of the eye. These particles may sometimes float into the field of vision and may be perceived as small, moving, dark shapes in the visual field. As this degeneration continues, the vitreous pulls away from the back of the eye. This is called a posterior vitreous detachment. A posterior vitreous detachment is not the same as a retinal detachment, which is discussed elsewhere on the website.
These floaters are better visible against a light, plain background and have been described as:
- Flying insects ('muscae volitantes').
- Small clouds.
Sometimes, as a result of the degeneration, the vitreous exerts traction on the inner aspect of the retinaThe retina is the receptor of light at the back of the eye. It fulfils the same function as the film in a film camera or the image sensor in a digital camera. The retina translates the images into electrical signals that are sent via the optic nerve to the visual cortex in the brain, where it is interpreted as the images we see. See Info on Eyes – Anatomy.. This leads to the appearance of flashing lights. If these light flashes are accompanied by a sudden increase in the amount of floaters, along with a decrease in the visual field of that eye, the possibility exists that the vitreous degeneration may be complicated by a retinal detachment. In these circumstances, an eye specialist should be contacted as soon as possible.
Risk Factors for Vitreous Floaters
- Nearsightedness/myopiamyopia is also known as nearsightedness. It results from an eye that is larger in size compared to a normal sized eye and/or a cornea that is relatively too steep, causing the image to focus in front of the retina instead of on the retina itself. See Info on Eyes, Optics and Refractive Errors - myopia..
- cataractA cataract forms when the natural lens in the eye is, or is starting to become, opaque. If not treated, it can lead to blindness, which in most cases can be treated. See Cataract Centre – Understanding Cataracts. surgery.
- YAG laser surgery.
- Inflammation in the eye.
- Diabetes mellitusDiabetes mellitus, or simply diabetes, is a group of metabolic diseases in which the ability to process glucose is impaired. If left untreated, diabetes can cause a host of long-term complications, including damage to the retina..
In general, no treatment is required, as there is no danger in leaving it as is. Should the floaters be very dense and cause significant obstruction to the vision, the whole vitreous may be removed by means of a vitrectomy. This is, however, only indicated in the most severe cases for two reasons:
- The risks involved in the surgery greatly outweighs the advantages.
- The ongoing process of degeneration usually treats the condition in a natural way. While the degeneration progresses, the vitreous liquifies, allowing the veils and clumps to settle in the bottom half of the eye below the visual axis, with the result that the line of vision becomes unaffected.
The practice of disintegrating large vitreous floaters into smaller ones by means of YAG laser 'vitreolysis' recently gained some attention in the medical literature. There are, however, certain risks involved, namely:
- Co-lateral damage to the crystalline lens or retina.
- The precipitation of a retinal detachment.