Every behavior has a reason the first step in changing or extinguishing a behavior is find out why he is doing the behavior.Children with autism often have sensory sensitivities and it maybe too much light, or he may have a physical problem such as dry eye, or he may need glasses. I know that sometime when I was not wearing my glasses my eyes began to hurt and I blink more often. Watch your son and maybe even keep track of when he does or does not close his eyes then look for the stimulus. Is your son verbal or non-verbal? If he has any communication see if he can let you know why he is doing this. Role play works well in developing communication skills. Show your son what you see him doing and then let him know why you are concerned. Watch your son and maybe even keep track of when he does or does not close his eyes then look for the stimulus. First I would check to see if there maybe a medical or physical reason. If nothing can be found medically or physically then start looking for when, why and hows that cause him to do this. To end the behavior find a replacement behavior such as a stress ball or something else for him to do that is safe and age appropriate.
rsaffran.tripod.com