Eye indentations are an easy way to give your amigurumi faces a cute look without having to crochet or sculpt the shape beforehand. It makes the cheeks stand out more too.
Strong thread in similar colour of your work. I used mercirised Bonbon/Sweet Treat by Scheepjes.
Use a long piece of thread on your needle.
First insert your needle near the neck at number 1 all the way up to number two in a stitch in the corner of the safety eye like shown in photo. Be sure to leave a long tail sticking out of 1.
Insert needle in 3 one stitch above 2 all the way to 4, the stitch next to 1 out of the head.
There will be a little stitch visible right in the corner of the eye.
Pull both threads very tightly and tie together a few times to make sure it won't unravel. The face will now have an indent!
The stitch we made in the corner of the eye will be invisible now.
Here's a view of the indented versus the non altered side of the face. Repeat same steps for the other side and finish off your amigurumi!
Tuck in ends that are still sticking out of the head and you're good to go.