I decided that I wanted to try to make a “Pixar” looking eye from the tutorial that is on Blenderchar http://blenderchar.weirdhat.com/eyetute/.
I did an ok job and so I decided that I would play around with a simple eye rotation. While watching the animation I noticed something strange. I’ve posted an image of it here. Does anyone have any idea what might be causing the “distortion”
Thanks!
Harnak
Looks like a part of the iris is “missing”…
Are you sure that you placed the iris in the correct position before joining… Looks like you got a “gap” there…
Unless I could take a look at your .blend (if it’s possible…) to see exactly what you’re doing, I don’t think I can tell for sure…
I see that Lyubomir at his tutorial is using SubSurfs to model each element of the eye…
Have you tried to convert to Mesh??? sometimes the textures on SubSurfs get crazy when the angle is changed during animation… This could also be an explanation for this distortion…
One example is this:
https://blenderartists.org/forum/viewtopic.php?t=13121
How is your texture maped on the iris???
<EDIT> One way to check if my theory is right is to render a still image with the eye in the “problematic” angle… Before you render rotate the texture space… This is done like this:
In the edit buttons press the button labeled “TexSpace”… You’ll see a “rectangle” around your model… Press Ctrl+A and confirm that you want to apply size and rotation… This should rotate the tex. space… Try to render now and see if the problem is fixed… If it is fixed, you need to convert your “eye” to Mesh (Alt+C), so that the texture is mapped much better on the model…
</EDIT>
I think if you could post the .blend it would be better, because we would have the chance to see what you’re doing there…
I’ve put the blend on the website. I also tried to convert it to a mesh but it didn’t seem to change the results.
Thanks
Harnak
The link seems not to be working… I can’t download the file… 
It seems to me that it is a texturing problem anyway…
How did you map the texture on the iris???
Try to fix the link to the .blend so I can take a look and see for my self…
The website link is working now… Seems I forgot how to spell originally hehe…
Do you mean what did I map it as, ie) cube, flat, sphere?
Harnak
Never mind that I’ve fixed that for you…
Here’s your eye…
I think it looks better now…
Now if you say PLEASE, I’ll tell you what I did to fix it… 
Naaahhh joking…
Go to the texture buttons and press for the iris texture “Clip” instead of “Repeat”…
Then go to the material buttons and change the settings like this…
And your eye will be fine…
I think I need to change my profession… I would be very good as an opthalmologist…
Ciao…
Thanks!!! Opthalmologist eh… lucrative profession I hear.
Could you take a second and explain to my why this fixed it? (I just gotta know why sometimes)
Thanks again.
Harnak
Actually what fixed it, was the “Clip” button that you pressed…
You see by repeating the texture you were asking from Blender to repeat the image on the surface of the iris… Only the image (eye.jpg) that you used didn’t have only the iris pattern but also a white border around it…
The “artifact” that you had was exactly the white border around the greenish pattern…
Also by telling Blender to map it flat, it stretched a little bit the image on the surface of the Mesh so that it would bring it exactly at the center,while the white border would be “out of sight”… and all the rest of the settings (x,y,z) were actually an attempt to try to bring it in the correct position (that’s it is called fine tuning the x,y,z coordinates… :P)… Your SizeX,Y,Z settings were o.k. Have in mind that when you reduce them the image texture gets “magnified”… when you increase them it’s the opposite…
I hope this solves your questions…
Happy Blending my friend…
Spyros.
BTW. in case you use these eyes on a character you’re planning to model next, have in mind that it is “shortsighted”…
I modelled a nice pair of glasses for you, so that the character will be able to see finel…
Next thing I’m gonna do is to write a tutorial on: “How to cure cataract with SubSurfs…”
(just joking… ok??? :P)
I hope I’ve helped you enough my friend…
Keep Blending and keep asking questions… 
See ya around… 
Spyros.
Thanks… I understand what was happening now. Thanks for taking the time to explain it and to create some glasses. I can’t imagine what the char would have looked like squiting to see things in the distance…
I appreciate your time,
Harnak