Flying flies, called myodesopsia in medical parlance, often appear when looking at the sky, ceiling, or other homogeneous, bright surface. They are not, however, real external objects. Most of the time, this phenomenon is not serious and the brain eliminates these annoying images on its own. However, it may be necessary to consult a doctor to identify the cause.
1. Aging of the vitreous body, the main cause of flying flies
The vitreous body is a gelatinous, transparent mass that fills the eye. It is located behind the crystalline lens, which is the lens used to focus to clearly see an object or a person. With aging, the vitreous body changes little by little. It liquefies and shrinks, causing it to peel off, which causes these flying flies to appear. As the National Union of Ophthalmologists of France specifies regarding these floaters, “age favors their presence, and we often see their increase when vitreous detachment occurs after the age of 50, which is a normal phenomenon.“. This aging phenomenon generally begins around the age of 25. Flying flies in the eyes linked to the aging of the vitreous body are not serious, and do not usually require medical treatment.
2. Flying flies in the eyes: other possible causes
Several factors can contribute to the appearance of floating flies in the eyes. Myodesopsia can, for example, be caused by:
- fatigue, which can exacerbate the phenomenon, especially when we spend a lot of time in front of screens;
- iron deficiency, because a reduction in red blood cells affects the oxygen supply to tissues, including the eyes;
- vitamin B12 deficiencies, because this vitamin is essential for the formation of mature blood cells and the proper functioning of the body as a whole;
- myopia, because this vision disorder causes changes in the structure of the eye which favor the formation of myodesopsia.
3. Flying flies in the eyes: when to consult?
In rare cases, flies in the eye may be caused by a more serious problem. If the appearance of flying bodies only affects one eye, if it is accompanied by flashes of light or blurred vision, this may be a sign of posterior vitreous detachment. The Paris Seine-Saint-Denis University Hospitals specify that these symptoms, added to the appearance of distorted lines or altered visual field, can also be signs of retinal detachment. In these cases, it is necessary to consult a healthcare professional urgently to benefit from appropriate care.
Sources
- Vitreous floaters, National Union of Ophthalmologists of France
- Retinal detachment, Paris Seine-Saint-Denis University Hospitals
- Myodesopsia or vitreous floaters, Barcelona Ophthalmological Center, April 12, 2019
- Flashes of light and floatersDr. Christopher J. Brady, The MSD Manual – Consumer Version, June 2021