Hi.
Great work! I am impressed! I have been using Inkscape for a few months and can hardly make a straight line!
(Thanks to brynn for the line tutorial!)
As a beginner with Inkscape I am also trying to learn how to draw an eye (or two!).
( My artistic skills are worse than yours - but I am trying and I learn a lot in the process).
By using the tool just in front of you - the computer - you can find a lot of info.
Try using your favorite search engine and type "close up picture of eye" - I am using Google - Image search.
You will see that the highlight "reflects" (pun intended) what the eye are looking at.
In a studio picture you can see one or more round highlight reflections of the studio lights.
If a picture of the eye was taken without any artificial light - in a room - the highlight will show a window (square).
An outdoor picture will normally have the sky reflected in the highlight.
The iris of a human eye are normally not colored evenly - there are "imperfections" or "spots" - if you are after a "realistic" eye this might be worth adding.
By searching for "how to draw an eye" you can find a lot of tutorials on how to get the right shape etc.
A very impressive Inkscape image of Aishwarya Rai can be found here:
http://imppao.deviantart.com/art/inksca ... ?offset=10unfortunately the link to the SVG file on the page does not work but the file can be found here:
http://imppao.free.fr/piwigo/picture.php?/70/category/2( Click on the floppy disk icon to download the file ).
I have used this file for "reference" trying to make something similar. As a bonus; by using the file you can see how to make "realistic" hair as well!
Another source worth looking at is the "AI - Adobe Illustrator" tutorials - here are some links worth studying:
http://www.aivault.com/2008/06/08/an-ex ... al-part-1/http://www.aivault.com/2008/06/10/an-ex ... l-part-ii/http://vector.tutsplus.com/tutorials/il ... ailed-eye/http://vector.tutsplus.com/tutorials/il ... r-eyeball/http://designbeep.com/2012/08/08/26-bes ... tutorials/http://www.youtube.com/watch?v=8BPfk-zwk1gMost - if not all - of what can be done in Adobe Illustrator can be done in Inkscape as well - for free!
By the way - here are part of my attempt at a portrait of one of my daughters -
the image is still "under heavy construction" experimenting with the make-up, skin-tones etc!

Click image for larger version.
(Edit: Used the "latest" image - the one originally there was from incorrect "fork" - saving different versions as I go along!
The project has been idle for a while - might go back trying to finish it one day as I now have learned how to make my own
color palette matching the skin colors etc!)
Good luck - Post your results here - it's a great way for the rest of us to learn!
RGDS
Ragnar