All About Eyelashes / Jane Conner-ziser
Eyelashes are a very small part of portrait work, but make a big difference in the expressiveness of the eyes. Sometimes they are a bit sparse and if you are lucky, you can copy and paste a couple of them here and there to fill in, but other times there is little to use and you have to put them in “from scratch”. If you’ve never tried to draw them before it can be daunting, so allow me to offer you some simple guidelines that will help you draw and paint them with confidence:
First we have the image of the eye:

Think of the eyeball as a wheel and the pupil of the eye as the axel. Eyelashes grow from the center like spokes on a wheel:

Notice that just above and below the pupil, in the peak of the arch of the eyelids, the direction of eyelashes is nearly vertical. From there, the eyelashes point towards either the nose or the outside corner of the eye. This remains constant no matter which direction the eye is looking – look at your own images and see the different directions eyelashes grow depending on where the subjects are looking. You do not have to change or “correct” this; it’s already right. Your job is to enhance, fill in or shape what is already there.
The eyelashes are shorter towards the nose and longer towards the outside corners of the eyes:

In photographs, eyelashes rarely show very far towards the nose from the edge of the iris on the top lid or the edge of the pupil on the bottom lid: