After how long a new baby born will be able to see his parents?

Immediately: Immediately, unless he has to be in an icus.

They can detect: Lights and motion initially. They are very nearsighted - that means everything they see is blurry. They start tracking by three months old, by 4 months they can detect objects about 12-18 inches in front of them and at 6 months they can differentiate objects . By 2 years , vision is almost perfect 20/60.If problem with eyes , go see pediatrician who then refer you to eye doctor