I became fascinated by the subject of heterochromia ever since I realized, on closer inspection, that one of my friends had heterochromia, or differently coloured eyes. In fact, they have both types of heterochromia - heterochromia iridum (where both eyes are different colours), and central heterochromia (where a different colour is present round the iris; the main body colour of the iris is the true colour of the eye).
I myself have central heterochromia (blue eyes with a central yellow ring). This project's still in its infancy, and I will get back to it when I have more time, but I ultimately aim to make an "eye bank" of drawings (different eye colours, races, etc.). These paintings are made using mixed media (pencil, conventional and UV acrylic paints) on hot pressed Waterford paper.
I am not limiting myself to human subjects alone, as animals and birds also show very interesting heterochromia. If you would like to contribute (and also have a drawing of your or your pet's eyes), email me a good quality photo!