The fusion frequency of flicker (F.F.F.) of 40 pupils were examined every day repeatedly, from Monday to Saturday. (1) The individual Variations of F.F.F. were statistically highly significant, p < 0.01 (2) Day to day Variations of F.F.F. were statistically highly significant, p < 0.01 (3) The interaction between age and weekly change was highly significant, p < 0.01 (4) The interaction between sex difference and weekly change was also significant, p < 0.01 (5) The interaction among age, sex and weekly change was significant at 1% level of significance.