Saccades are just swell
I’m going to bet you’ve never heard of saccades. Or saccadic movements. They are the jerky movements our eyes make when moving from one object to another. It’s pretty much impossible for most people to move their stare smoothly across the room - our brains naturally jump our eyes from one point of interest to another. Try it now. See? That’s saccades that is. The best way I know of moving your eyes smoothly is to fix on a point and turn your head.
Because your eyes move with incredible speed ( there’s a wikipedia explanation of the arcs and angle and things involved here) when ‘jumping’ from one point to another, you can experience some cool side effects. Some can be experienced when you’re out driving on a motorway. Best done if you are a passenger if you want to avoid crashing. Look at a car in the lane next to you. Now glance forward. Due to ‘persistence of vision’ you will experience, for a split second, a frozen image - in particular you’ll see the car’s wheels appear to have stopped turning. It takes a bit of practice, which is why it’s definitely best not to be driving at the time.
You can notice a similar effect with certain types of lights - do a saccadic jump and you’ll get a ’strobed’ effect trail if the light in question is an LED brakelight, or a 50Hz streetlight. With some of the new xenon headlamps, you can also get a streaked-out spectrum as these lamps emit over a range of light frequencies.
Anyway, that’s saccadic eye movements.
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