Is it realistic? It is a Side Eye View drawing. 
I tried with 2B with a loose sketch of a circle with small bump (cornea) on side, a curved line from top and bottom of cornea to form iris and a thin oval inside iris to form a pupil. Then upper and lower eyelids sketched loosely and freely by 2B. A curved outline drawn inside eyeball then the pupil shaded fully. This how i did the eyeball. Comment your view on this art.