It depends or your definition of eyestrain. I generally consider to be a feeling of soreness, fatique and some blurry vision associated with prolonged, concentrated visual effort. So according to my definition, it is certainly possible to get eyestrain. Now is you consider it to be a strain like staining a calf muscle or something like that, then I suppose it would be very difficult to (by yourself) "strain" the eye in that manner in which actual physical harm was done.
MJK MD
http://www.ergonomicsmadeeasy.com/eyestrain/
The mind receives messages from sensory cells. The mind can focus on sensory signals from the eye. Eyes that have become strained do not always deliver a clear signal. Inattention to eyestrain symptoms deprives the brain of meaningful signals.