Myodopsies are small spots that appear in the vitreous humor of the eye, whose appearance is similar to that of a fly. Although they cause some difficulties in vision, they are usually harmless. Nevertheless, they can sometimes indicate the presence of an ocular pathology.

They are one of the most recurrent reasons for ophthalmological medical consultation, although they are not usually dangerous. In this article we will see an explanation of what myodopsies are, what the main causes are and the most common treatments.

The human eye system

Our eyes are composed of a very complex ocular system made up of an outer layer, a middle layer and an inner layer of cells, tissues and nerve terminals in charge of carrying electrical signals to our brain.

In turn, each layer is composed of other segments that have specific functions. The inner layer, for example, is composed of three distinct chambers or sections; an anterior chamber between the cornea and the iris, a posterior chamber between the iris, ciliary body, and crystalline lens; and a vitreous chamber, between the cornea and the retina.

It is in the latter that we find a colourless, gelatinous mass which we call the vitreous humour or vitreous body , which has a protective and cushioning function with which it is possible to maintain the shape of the eye and its internal pressure.

What are myodopsies?

Myodopsies are an ocular alteration that causes spots, dots or threads of different size and consistency within the vitreous humour of the eye, that is, in the gelatinous mass that is between the lens and the retina.

In formal terms, myodopsies are defined as an entopic phenomenon (that is, one that originates and manifests itself inside the eye), caused by some defects in the vitreous gel that reflect, absorb or scatter light and thus interfere with its passage.

On the other hand and in more colloquial words, myodopsias are known as “floating eyes” or “flying flies” because they are shaped like a spider web, a lint or a small spot, usually black or gray, that moves and floats inside the eye.

That is why some research recognizes cell type myodopsies or filament type myodopsies. Although they can obstruct vision, and are one of the most common reasons for ophthalmological consultation, myodopsies are not particularly harmful.

They occur more frequently during ageing due to important changes in the cellular composition of the vitreous humour caused by the natural passage of time.

However, if the number of myodopsies increases suddenly and is accompanied by flashes of light, it could indicate the presence of a more serious pathology (such as a detached retina), so in any of these cases it is important to consult a specialist immediately.

Main causes

Myodopsies are the result of an increase in cellular debris in the vitreous humour, i.e. they are mainly caused by changes in the cells that produce the gelatinous substance of the vitreous humour inside the eyes.

During ageing, this substance becomes more liquid, so that the fibres and cells of the eye are easily grouped together, generating spots or shadows on the retina that at first glance look like small flies.

At other times, the presence of myodopsies may be an indicator that the eyes are inflamed or damaged, so they may be accompanied by internal bleeding that in the worst case results in vision loss.

They can also appear as a consequence of a detachment of the posterior vitreous, or due to ocular trauma, surgical interventions in the eye, or as one of the effects of myopia .

Most frequent treatments

Usually the flies disappear on their own after a few weeks, without having caused any significant discomfort. This means that they do not require special treatment and there is no definitive medical treatment.

Nevertheless, and given that they occur more frequently during ageing, which in turn increases the likelihood of retinal detachment, it is advisable to see an ophthalmologist whenever there is a sudden increase in the size of the patch, a peripheral shadow in the field of vision or a sudden decrease in vision.

From then on, the treatments recommended by the specialist will be those appropriate to the pathology detected, which may include a vitrectomy (surgery to remove the vitreous humour and replace it with a saline solution). In the meantime, it is recommended not to chase the spots with your eyes, since this can worsen the quality of vision.

Bibliographic references:

  • Myodesopsies (2018). What are myodesopsies? Recovered March 4, 2018. Available at http://miodesopsias.com
  • Castilla, M., Borja, C. & García-Arumí, J. (2016). Impact of myodopsies on visual quality. Doctoral Thesis, Universitat Autònoma de Barcelona.
  • Clinica Oftalmologica Castillo. (2013). Stains or floating flies. Recovered March 4, 2018. Available at http://www.oftalmologiacastillo.com/enfermedades/manchas-o-moscas-flotantes/
  • Puel, C. (S/A). Physiological optics. The optical system of the eye and binocular vision. Complutense University of Madrid [Electronic Version]. Retrieved March 4, 2018. Available at http://eprints.sim.ucm.es/14823/1/Puell_Óptica_Fisiológica.pdf