After sitting at the computer all day, I do some stretches to relax my eyes and back.

relax 是动词，意思是"放松、使松弛"，由前缀 re-（表示"重新"）和拉丁词根 lax（意为"松的"）组成，字面意思是"使重新变松"。在这里指通过伸展运动让紧绷的眼部和背部肌肉得到舒缓。