well if you use photoshop you must use a screen brush to delete the shadow. Another way might be the Colorise brush of zbrush. If you put some more white not on the 3d surface beacuse this will not avoid the fact that your eyes are shadowed. You must process it as 2d image, in a few word you must exit transorm mode.I can try myshelf if you want further advice.
Also shadow (something) brush and glow brush can achive the same result. Just import it as 2d image and use one of these brush and you will achieve the result you want. Another way is to increase the ambient for the material of the eyewhich is the best and safest way .Play with the material option especially Ambient , Difuse and Specular and you will avoid the shadow