Floaters

We’ve all had that childhood sisters/brothers who used to terrify us by saying dreadful stories or something that doesn’t even exist. I must have been in my 1st or 2nd grade when I was introduced to the concept of ‘glassics’. Let me tell you what glassics are.

On a sunny day, when you stand out for a long time, you get to see that arrow/worm-like thing floating in the air, in your field of vision. You might even have experienced it while glancing at similar uniformly bright objects, say, a blank computer screen or even snow.

My then neighbour and senior at school used to spin stories around that, telling me that these are worms flying around in air causing infection to people. The highlight is that I believed all these for a few years until I knew that particles or organisms in the air cannot be seen with naked eyes. Even after this basic enlightenment, I didn’t know what these ‘glassics’ were and eventually forgot about them.

A few years back, I came to know that these so-called ‘glassics’ are nothing but one type of entoptic phenomenon, through a TED video. An entoptic phenomenon is a visual effect that occurs under suitable conditions of light and whose source is within the eye itself.

The tiny dots of light darting about when looking at a bright blue sky is known as the blue field entoptic phenomenon. These bright dots appear to move rapidly along squiggly lines in the visual field.

Source: Google Images

It is caused by white blood cells moving in the capillaries along the retina’s surface. Because the space and the white blood cells are both more transparent to blue light than the red blood cells normally present in capillaries, we see a moving dot of light wherever this happens, following the paths of our capillaries and moving in time with our pulse. Under ideal viewing conditions, we might even see a dark tail following the dot. The tail is the red blood cells that have bunched up behind the leukocyte (WBC).

While all of us experience these sorts of visual effects, the number and type vary greatly. Most often, it appears only when it is focussed upon and disappears when we ignore it. However, in case you see abnormally large or so frequent particles that block or interfere with your vision, it may be a warning sign to a medical condition and it may require a diagnosis.