This is a face anatomy study of 4h sculpt of an old Mapuche man.
For the wrinkles I didn't use any custom brushes just used the preset brushes in ZBrush. Mainly I used Standard-Brush with Alpha 58 in Color Spray mode, Dam_Standard and used some noise as a base.
The material used for the eye is ''Wet-Eye-Material'' created by James K.
You can find it at this link: https://www.artstation.com/marketplace/p/xW1j/wet-eyes-material-obj