To Donate Eyes

A father was travelling with his son on the train. While looking outside through windows of the train, the child was becoming very very happy, uttering something something, sometimes he was asking from his father about the color of trees, scenery and continuously speaking. the people sitting beside him/other travelers were getting annoyed, where as the father of the child was looking happy/pleased with the child. After some time a person sitting beside the father murmured to him "why don't you admit your son in mental asylum, as he seems to be sick. The father smiled and answered my son was blind. Somebody has donated his eyes to him. Soon after the operation ,he is travelling first time on the train. Therefore.............
a)We simply should never judge another. 
b)Secondly, if possible ,we should donate our eyes after our death ,to enable blind 
people to become happy like the child of the above story.