Using Photoshop 3/D to Draw an Animal Eye

 In Photoshop Window tab choose 3D create file from Mesh.

 When Asked do not switch to 3D workspace.

An eye is basically a sphere. To look correct, the light must be directly from the front .   Move the light around to be seen from the front.  The light view is the smaller window.  The light is directly in front of the sphere.

Here is Vivid Light.

Here is the light in front of the sphere.

Go to layer an flatten your sphere when it looks correct.  If it does not flatten with direct front light try again.

Here I duplicate the one sphere and free transform it to be just a little smaller and position it right above the first sphere.

To make it just a little wider I went to edit, puppet warp and placed two pins opposite of each other on the side and elongated the sphere slightly.

I want to color balance and changed the color of the second speaker to red and yellow all the way to make a brown ring.

I then used the shape tool to create a perfect circle shape holding the shift key 

as I created the shape in the pixel mode so I would not need to rasterize the shape. I chose the color of dark brown.

With the shape selected, and using the gradient bucket with black and brown in my color swatches and the circular gradient mode in the top menu, I added a gradient to the shape on a new layer.

The eye is starting to look more real, but when I check an animals eye, the gradient will not look quite real.

To remove  the line, I selected the shape. and under modify I  chose expand.

I chose to expand by one pixel.

Under filter I chose Gaussian  Blur.

 I blurred a great amount, to look real, but it is still solid.

On the white background layer I change the channel and output to a darker color to show the dark layer on the outside of an dog's eye.

 At this time I am looking at the eye and the dark ring, making sure that I am ready for the highlight.

I duplicate the layer so I can add specks.

 On the new layer and changed the opacity. I then change the mode from normal to dissolve to create the little specks seen in an eye. 

One more time with the shape tool I create a small white circle shape. I duplicate the small white shape.

 That first shape is soft, so I choose a Gaussian Blur to soften it out.

Then with the second white shape I edit transform it and change the opacity to be a little softer.

The eye is looking quite real here, but still has more highlights in the wolf photo.

Duplicating the highlight, I move it to the outer edge of the black outline.

I change the transparency of the highlight, and then notice that this should line up with the highlight.  Then I edit transform and flip horizontal.

The Highlight is then in the correct place, I save it as a Photo shop document.  Then I flatten the eye and save it as a large jpg.  The eye is then ready for use in a front on dog drawing.