▁move ▁smooth ly ▁across ▁the ▁printed ▁page ▁during ▁reading . ▁Instead , ▁they ▁make ▁short ▁and ▁rapid ▁movements ▁called ▁s acc ades . ▁During ▁each ▁sac cade ▁the ▁eyes ▁move ▁as ▁fast ▁as ▁they ▁can ▁and ▁the ▁speed ▁cannot ▁be ▁cons ci ously ▁controlled ▁in ▁between ▁the ▁fix ations . ▁Each ▁movement ▁is ▁worth ▁a ▁few ▁minutes ▁of ▁arc , ▁at ▁regular ▁intervals ▁about ▁three ▁to ▁four ▁per ▁second . ▁One ▁of ▁the ▁main ▁uses ▁for ▁s acc ades ▁is ▁to ▁scan ▁a ▁greater ▁area ▁with ▁the ▁high - resol ution ▁f ove a ▁of ▁the ▁eye . ▁Research ▁conducted ▁by ▁the ▁University ▁of ▁South ▁Australia ▁in ▁partners hip ▁with ▁the ▁University ▁of ▁Stuttgart ▁has ▁revealed ▁the ▁relationship ▁between ▁eye ▁moment ▁and ▁person ality ▁tra its ▁that ▁A I ▁can ▁read . ▁ ▁V est ib ulo - oc ular ▁system ▁ ▁The ▁visual ▁system ▁in ▁the ▁brain ▁is ▁too ▁slow ▁to ▁process ▁that ▁information ▁if ▁the ▁images ▁are ▁sli pping ▁across ▁the ▁ret ina ▁at ▁more ▁than ▁a ▁few ▁degrees ▁per ▁second . ▁Thus , ▁to ▁be ▁able ▁to ▁see ▁while ▁we ▁are ▁moving , ▁the ▁brain ▁must ▁compens ate ▁for ▁the ▁motion ▁of ▁the ▁head ▁by ▁turning ▁the ▁eyes . ▁Another ▁special isation ▁of ▁visual ▁system ▁in ▁many ▁verte br ate ▁animals ▁is ▁the ▁development ▁of ▁a ▁small ▁area ▁of ▁the ▁ret ina ▁with ▁a ▁very ▁high ▁visual ▁ac u ity . ▁This ▁area ▁is ▁called ▁the ▁f ove a , ▁and ▁covers ▁about ▁ 2 ▁degrees ▁of ▁visual ▁angle ▁in