Spasm of accommodation

Spasm of accommodation means spasm of eye muscles. With nearsightedness (myopia) oblique eye muscle spasms and oblique eye muscle cannot relax and unclench when a person looks at a far distance. With farsightedness or in other words hyperopia. Straight rectus eye muscles are spasmodic and cannot relax when a person looks at a near distance.
How spasms of accommodation happen
For example, a person working at a laptop for 3 hours, without looking in any different directions and without small breaks. He greatly overstrains his oblique eye muscles with the same distance to the screen and he does it every day. When he comes out from work, he looks at the same distance to his phone. Long-term eye fixation at the same distance can push eye muscles to a spasm because they didn`t get a chance to rest, relax and refocus.
How to get rid of a spasm of accommodation
Just give your eyes rest, at least every 20 minutes of screen time, actively look around to refocus to a different distance. Change distance to monitor, so eye muscles work will be different and eyes will get rest.