We receive approximately 90% of our visual information from the outside the eye – but did you know that we can sometimes see the structures of our own eye?

If the eye is healthy, under certain conditions, it is able to perceive its microenvironment: the blood vessels that feed it, the gel that fills the eyeball, even its own blood cells. These perceptions, as defined by Helmholtz, are called ‘entoptica phenomena’. You’ve probably seen parts of your own eye, but you did not realise…

What are the most common phenomena?

Floaters or muscae volitantes – are slowly drifting squiggles or clouds of varying size and shape, which are most noticeable when lying down looking at a bright, plain background, such as the sky. The cause are the natural irregularities that exist in the vitreous gel that fills most of the eyeball.

Blue field entoptic phenomenon – are tiny bright dots moving rapidly along squiggly paths in your vision. They are most noticeable when looking at blue light. These are white blood cells moving in the capillaries in front of the retina (the thin wallpaper of the eyeball).

The Purkinje Tree – If you have ever had an examination of your retina (at the back of the eye), you may recall that you could see branches and lines through the bright light. They are the retinal blood vessels that can be seen by shining the beam of a small bright light through the pupil in dark room. Under normal circumstances, they are not seen due to brain adaptation to their fixed position.