The grating acuity of the deprived (orange symbols) and nondeprived (green solid symbols) eyes as well the binocular acuity (green open symbols) of two pairs of monocularly deprived kittens surrounding 10 days of total darkness followed immediately by an 11-day period of fellow eye occlusion (FEO). As with previous figures, the visual histories of the animals are depicted in schematic form by the bars above the two graphs. (a) Data for C390 (square symbols) and C393 (circle symbols). (b) Data for littermates C419 (square symbols) and C420 (circle symbols). The period of FEO effectively blocked any improvement of the acuity of the deprived eye following the period of darkness but did cause a reduction of the acuity of the nondeprived eye.