These plastic eyes come with a long shaft, making them easy to apply through almost any fabric, and a metal backing to hold it secure. No sewing involved! Total diameter is 15mm, with a 12mm shaft.
The iris of these eyes is clear, but they'll pick up and magnifiy any colour behind them. You could paint the backs, or put a tiny felt circle behind them to give your creation any eye colour you desire.
Price is per pair.