Stimming or Stemming, kind of like tomay-to or tomah-to stems from repetitive self-initiated stimulation, and in the visual sense it can often be seen among children on the spectrum through the following behaviors:
While flapping hands is easy to think of as stereotypy, I hadn’t really thought of looking out of the corner of the eyes, or the sideways glances as a stim. I’d always considered it part of the eye contact problem. For that matter, facial tics or the repetitive deep wink that some kids exhibit might be a stim for ASD children as well. The chart above is from autismhelpers.com and they have some nice charts for the other primary senses as well.
There is some good advice on how to decreased or discourage stimming:
I particularly like the latter site, which notes the following:
I have found that visual “stim” behaviors serve one of several purposes. First, they are often very calming and organizing when children are overstimulated, second they may be a means of stimulation when a child is underaroused, or they may be a means of visual input when a child has poor oculo motor contol and does not get meaningful information from their environment. I would first look at his overall level of arousal. It is the end of the school year in most places and the increase you see may be a response to this time of increased arousal level. If this behavior is relatively new or suddenly increasing this may be the case. I would look at how stimulating things have been, has he had enough “down” time, have ther been alot of changes in routines? If so you may need to increase his sensory diet activities with lots of heavy work or movement as works best for him. I would also recommend an eval by a good behavioral optometrist who can look at his functional oculo-motor skills, eye teaming, convergence skills, tracking, etc.