Here is a brief explanation how to draw eyes and directions of view. You can also see the process of drawing eye in my Video.
In the sketch below I chose different viewpoints. Eyes seen from a slightly lateral position, frontal, eyes looking up and down from a higher position.
It is challenging because the are not on a straight but on a curved line due to the fact that they lie on a curved / round surface.
The eye shape is similar to the almond shape, however, be aware that the upper and lower lines are not symmetrical. You can also see the differences between inner and outer corner of the eye. From a frontal perspective the outer corners is slightly higher. Also, the margin of the lid is usually visible as can be seen in the sketches.
At the edge of the eyelids are the lases. The curve and direction of the eyelashes varies with perspective.
The eye shape has to be adjusted to the perspective. At first this may seem difficult, but with practise you get a feeling for it. It is also very important to make sure that both eyes and lenses of the eye look in the same direction.
The best thing is to observe various eyes from different perspectives.
It also helps to look at pictures and analyse the eyes with a ruler. So you can find out measurements or symmetries and asymmetries by yourself.