Hello Ivan Mishchenko !
The easiest ways to do it are the following:
1) Upload the new icon pic via Studio->Navigation->Persons->View profile area. Click this item there and upload the new one.
2) Change it via Studio->Protean->Styles->Large buttons, the Font color part. But in this case, all your menu on the site will have the new styles too.
3) Change it via Studio->Protean->Styles->Custom Styles area. Just set the new settings for the .sys_icon .eye CSS class. But in this case, all your "eye" icons will have the same look.