For the Mini girls collection I use embroidery eyes. These are a great alternative to plastic eyes and much safer, especially if it is made for a small child.
Steps to embroider eyes:
1: position 2 pins where the eyes will be embroidered. For the Mini Dolls I put them in row 11, leaving 8 sts between them.
2: Using a long strand of embroidery thread and needle insert the needle at the back of the head of the toy. Leave a long tail for tying it later. Bring the needle up at the bottom of the row where the 1st eye will go.
3: Insert the needle on the top side of the row and bring it out at the bottom again.
4: Repeat it 5 times.
5: When inserting the needle for the last time, do not bring it out at the bottom, but at the bottom of the other eye.
6: Repeat steps 3-4.
7: Bring the needle out at the same place on the back of the head where we started. Tie the tails together and hide the tail ends inside the head.