Eye floaters are small, seemingly animated spots that waltz through your field of vision. They are easiest to see when you gaze at something illuminated, like the bright blue sky.

We have all seen these at some point in our lives. I remember wondering what in the hell are these things? They truly did seem like little transparent creatures or amoebas or something.

Now we know what they really are and it’s kind of cool. For the most part, they are harmless, but in some cases, they could indicate disease within the body or tumors in the eye.

In this well-produced video below, TED Ed explains what’s going on with floaters and the Blue Field Entopic Phenomenon, “white blood cells moving in the capillaries in front of the retina of the eye.” They can be seen as darting dots of light when looking up at the blue sky.

The blue field entoptic phenomenon allows the perception of leukocytes moving in the retinal capillaries of one’s own retina. This phenomenon is not affected by media opacities provided that enough blue light reaches the retina.

The phenomenon was investigated in 63 amblyopic patients to determine if the perception of the leukocytes in the amblyopic eye differs from that in the good eye.

A difference in perception would provide a means of assessing amblyopia in eyes with opaque media. Ninety-four percent of the amblyopic eyes perceived less sharp particles, 83% perceived fewer particles and 60% perceived slower particles than in the good eyes.

In 86% of the amblyopic eyes, the tails were shorter than in the good eyes or absent entirely. The degree of amblyopia correlated with the difference in the number of leukocytes observed in each eye. No differences in the perception of leukocytes were reported by 20 normal subjects.

Most floaters are small flecks of a protein called collagen. They’re part of a gel-like substance in the back of your eye called the vitreous.

As you age, the protein fibers that make up the vitreous shrink down to little shreds that clump together. The shadows they cast on your retina are floaters. If you see a flash, it’s because the vitreous has pulled away from the retina. If that happens, see your eye doctor ASAP.

These changes can happen at any age, but usually, occur between 50 and 75. You’re more likely to have them if you’re nearsighted or have had cataract surgery.


It’s rare, but floaters can also result from:


  • Eye disease
  • Eye injury
  • Diabetic retinopathy
  • Crystal-like deposits that form in the vitreous
  • Eye tumors

Check the video below: