Dear doctor;

I keep seeing some funny spot in front of my eyes, but when I look into a mirror or even ask someone to check my eyes, there is nothing. Where is this spot coming from as it is not constant but on and off?

Shamim, 26, Kiyovu

Dear Shamim,

What you seem to be seeing is eye floaters, that is, small spots, threads or cobweb like strands, which appear in field of vision. They are particularly noticeable when one looks at something bright like a white paper or blue sky. Most eye floaters are caused by small particles of a protein called collagen. With aging, millions of fibres of vitreous humor (fluid present in posterior chamber of eye) shrink and shred. The shredded particles can accumulate locally. This results in change in the light beam that hits the posterior part of eye (retina), which is responsible for visualising the image. This process can occur at any time between 50-70 years of age.

In a young person, floaters can be secondary to some viral or fungal infection of the eyes. Mild trauma as in corneal abrasion, or any other injury to the eye, infection or inflammation of interior of  the eye can cause floaters. It can also be due to retinal disease, retinal or vitreous detachment. Damage  to retina or vitreous humor due to uncontrolled diabetes causes floaters as one of the symptoms. Rarely it may be due to congenital abnormality in periphery of retina.

It can be sequel to eye surgery, particularly cataract. Long standing near sightedness can also lead to floaters in front of eyes. It may be an accompaniment of migraine, a form of severe one sided headache.

Most of the floaters occurring in a young adult are benign and need no treatment. They  may be so small that although a person perceives them, the ophthalmologist may fail to detect them. The affected person gets over them after a few days and can see normally by just moving eyes in a particular direction, which offers better vision. Treatment is needed if there is sudden increase in number and size of floaters, it is accompanied by bright flashes of light, of if it is persistently present.