I became fascinated by the subject of heterochromia ever since I realized, on closer inspection, that a very good friend of mine 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). I am developing this project, which is still in its infancy, to make an "eye bank" of drawings. The UV pigments I use bring out the quality of fire and light in the eyes very well!
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!