Nice! I think you did a good job with the structure and edges. I feel like the forms are quite clearly defined. - When drawing an eye, i think it's a good idea to lightly indicate the entire eyeball in the early stages of the drawing, to make sure that you make it a sphere. In your drawing I get the feeling that the eyeball is slightly oval in form. - You might have made the part of the sclera that's in shadow too light. A helpful trick to get values right, is to squint at the refernce. If you do that, you might notice how the sclera in shadow, merges into a single shapes with the other darks. They are part of the same group. - You could also make the shadows darker, for a clearer read of what's in light and what's shadow. Hope this helps :)