What are floaters?

14/07/2022

Seeing “eye floaters” (or myodesopsia in medical language) is very common reason for people to go to the ophthalmologist.

It is a condition where we see spots, shadows or moving squiggles (often shaped like cobwebs) suspended in our visual field that move although the eye does not, and appear to flee 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”. They are perceived more intensely when gazing at an illuminated or brightly backlit surface, and are exacerbated by tiredness, stress and anxiety.

In the majority of cases, eye floaters are considered to be a normal and innocuous. The patient quite commonly feels very anxious at the start, but gradually learns to ignore them. 

Causes and risk factors

Generally speaking, these deposits of condensation are a result of the vitreous gel's natural dehydration, with age and myopia (short-sightedness) being the main predisposing factors. In terms of structure, floaters correspond to clusters of collagen fibres that form in the vitreous humour (transparent gelatinous liquid filling the eyeball), which project their shadow on the retina when light passes through. 

The most common cause of sudden onset myodesopsia is vitreous detachment. If the patient also sees flashes of light (photopsia), this may be a highly suspicious sign of a retinal tear. They are also common after cataract surgery or after cleaning the posterior capsule with a laser (capsulotomy). They are less commonly due to a serious eye disease: intraocular inflammation, vitreous haemorrhage or tumours.

Prevention 

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

At present there is no effective medical treatment to get rid of myodesopsia for good.

When the moving opacities significantly interfere with the eyesight or even become a psychologically intolerable problem, a vitrectomy may be indicated. In this procedure, the vitreous gel and condensation are extracted and replaced with a transparent physiological saline solution. It is a highly specialised and very effective intraocular surgery which is carried out in outpatients with a local anaesthesia. 

You should always see the ophthalmologist when floaters suddenly appear for the first time. And we also recommend your return if these floaters increase in number and size or are accompanied by light flashes or visual stimuli.

Dr. Sònia Viver, ophthalmologist at the Barraquer Ophthalmology Centre