Q. I was looking at the stars the other night and noticed that the star was moving…is this an optical illusion? What does this say about my eyes?
A: The illusion of the star moving around is due to very small, minute eye movements that keep a small, light image visible to you. On a large black sky, it makes the star appear as if it is moving when in fact it is your micro-saccades (small quick eye movements) that you are noticing. You may also have noticed that the star may have been flickering and that you could see it more brightly by not looking at it directly. This is because the peripheral part of your retina or the rod vision is more in tune for seeing objects at night. This part of the retina is also responsible for movement and reaction. Unfortunately, it is not as clear as your fovea or cone vision…so as your eye moves around the star is in and out of your central vision creating a flickering effect.
Optical illusions are a result of the very important part of your vision that is not central or 20/20. This is your peripheral vision, your movement cells, the “blurry” part of your vision that is necessary for speed and reaction. The human body could not function if it only had sharp, central 20/20 vision. Many people have inadequate visual function because this often under looked part of their vision may not be working. This can result in motion sickness, dizziness, and vertigo.
Below, I have attached a link to a very interesting optical illusion of your normal blind spot and how this blind spot can be very noticeable however, when an object passes it through it the optical centers in the brain fill it in so you don’t miss anything. This is very important for day to day functioning. Our eyes and our visual centers in the brain are quite amazing. Enjoy the link.
Dr. Patricia Fink
Millcroft Shopping Centre
2080 Appleby Line, Unit E6
Burlington, Ontario, L7L6M6
Tel: (905) 319-1066