Create a new file having 400x400 px and 72 dpi. Paint it in this shown color ? 353535.

Create Futuristic EyeBall in Photoshop CS

Take the next instrument and create a circle having the same color the background has.

Create Futuristic EyeBall in Photoshop CS

Blending
Options-Stroke

Create Futuristic EyeBall in Photoshop CS

Gradient?s parameters:

Create Futuristic EyeBall in Photoshop CS

Select the previous instrument to create one more circle inside that one we already have.

Create Futuristic EyeBall in Photoshop CS