The authors compare monocular and binocular development measures in 16 children with albinism, 10 with infantile nystagmus (INS) and 72 with normal vision to address interocular acuity differences, crowding ratios and binocular summation rates. The children were aged between four and eight years. There was no age difference between groups. Children with albinism and INS had significantly larger interocular acuity differences than those with normal vision for the single chart and uncrowded chart but no significant differences for crowded charts. Crowding ratios were higher for children with albinism and INS for binocular crowding and the poorer eye. For the better eye, differences were significant for INS only. There was no difference for binocular summation ratios across groups. Strabismus and nystagmus amplitude significantly predicted crowding in the poorer eye for albinism.