Floaters

Floaters, or in medical language, myodesopsias, is seeing moving floating bodies in the form of dots, shadows, threads, flies, webs or other shapes moving around the visual field, which, by definition, do not correspond to real external items. It’s one of the most common reasons for paying a visit to the ophthalmologist.

Despite the fact that the cause and effect relationship has not been accurately ascertained, age and myopia (short-sightedness) have been identified as the main predisposing factors. In terms of structure, floaters correspond to condensation (clusters of collagen fibres) that form in the transparent gelatinous liquid filling the eyeball, known as the vitreous humour, which project their shadow on the retina when light passes through. In the majority of cases, these condensation clusters are a consequence of the natural dehydration of the vitreous.

They manifests themselves as a group of moving stains, dots or threads (sometimes in the shape of  spider’s web) suspended in the visual field.  In terms of their characteristics, they move around as the eyes move and they seem to disappear when we try to look at them directly. They don't usually follow the eye movements accurately and, when focusing on objects, they generally move slowly as if “adrift”.

Myodesopsias are very common and most people learn to ignore them. They are typically seen more intensely when we focus our eyes on a uniformly lit surface with lots of background light (like a computer screen, when reading or even looking at the sky on a cloudy day).

The most common cause of floaters is vitreous detachment, the onset of which is almost always sudden. If the patient also sees flashes of light (photopsia), they may be a sign that something highly suspicious has caused a retinal break.

Seeing floaters is also common in people who have had cataract surgery and those who have undergone laser posterior capsule cleaning (capsulotomy).

Less commonly, myodesopsias can be part of the symptoms of a serious eye disease, the origin of which may be inflammatory (posterior uveitis), haemorrhagic (vitreous haemorrhages with a range of origins) or tumoral (intraocular neoplasia).

There is no way to prevent myodesopsias, since the main risk factors, which are age and myopia, are irreversible.

In the majority of cases, floaters are considered to be a normal and innocuous circumstance that does not compromise the eyesight. It’s common that the patient feels anxious at the start because of this symptom which, on one hand, comes and goes based on background light, and is exacerbated when the person affected is tired, stressed and anxious.

Currently, there is no effective medical treatment to get rid of myodesopsias for good.

In the most extreme cases, ones in which moving opacities significantly interfere with the eyesight or even become a psychologically intolerable problem, surgical treatment called a vitrectomy may be indicated. In this procedure, the vitreous gel and condensation are extracted and replaced with a transparent physiological saline solution.

A vitrectomy is a very effective and highly specialised intraocular surgery. It is performed under local anaesthesia and does not require stitches, however, due to its potential risks, though minimum, it is only indicated in cases where the symptoms are crippling for the patient.