When Ráma backward turned his eye, And saw the king his father lie With troubled sense and failing limb, And the sad queen, who followed him, Like some young creature in the net, That will not, in its misery, let Its wild eyes on its mother rest, So, by the bonds of duty pressed, His mother’s look he could not meet.

In plain words: Rama looks back and sees his father lying weak and confused, and his mother running after him. Held by his duty to go, he cannot bear to look into his mother's eyes, like a trapped young animal that cannot face its mother.