A couple of curving strokes, a circle for the iris, a black dot for the pupil, and a handful of short, fine lines can give you an eye. Where does it go wrong? In the context of a portrait. The eye changes depending on the angle of the head, lighting, position of the eyelids, and shape of the socket. Reproducing a well-known symbol for the eye instead of drawing those shapes means both eyes could end up looking similar even if your reference shows obvious distinctions.
Consider the eye ball as a spherical shape within the eye socket. The eyelids curve around the shape, rather than sitting flat on the plane of the face. This is why the upper and lower lids don’t simply act as two symmetrical arcs. The upper lid is generally a stronger shape and can cast a small shadow on the eyeball; the lower lid may be softer. Consider where each lid shifts in direction and what proportion of the iris is exposed rather than just completing the whole circle.
Take into account the other structures around the eye. The brow, nose bridge, upper cheekbone, and outer edge of the socket all play a part in how the eye sits within the head. Drawing only the almond-shaped eye opening can cause the feature to look as though it has been glued to the portrait. Prior to adding eyelashes and specular highlights, compare the distance from the eye to the brow, the angle to the nose, and the shadow around the socket. These larger relationships will tie the eye into the overall construction of the head.
As an exercise, select a reference with strong light, and blow up the image to examine a single eye. Sketch the area of the socket with light pencil, followed by the eye ball. Then block in the upper and lower eyelids. Omit the eyelashes, details of the iris, and reflections. Work only in a few value shapes to represent the dark upper lid, the shadow around the socket, and the shadow (if any) beneath the lower lid. Once the form reads without added ornamentation, introduce only what you see in the reference.
Examine both eyes within a completed portrait. A head in turn generally results in one eye being thinner, and perspective may alter the perceived width of the areas surrounding the eye. Even with a face that appears to be facing forward, there’s usually some asymmetry in the shape of the lids, position of the brow, and what portion of the iris is revealed. Copying the right eye and mirroring it to form the left tends to erase those nuances. Observe each eye separately, while keeping both in relation to the same center and eye lines.
Pencil weight may also cause the eye to lose volume. Heavy contouring around the eye’s perimeter can give it a crisp outline, which doesn’t appear in the reference everywhere. There might be a defined line along the top of the lid or near the tear duct, but other edges can soften and fade away into shadow and skin. Softening the line lets the eye appear to sit into the face rather than resting on top. Reserve the darkest values for those areas that truly appear dark, such as sections of the pupil, lash line, and deepest creases.
When your eye study looks overly illustrative or comic-booky, forget about the lashes and iris. Concentrate instead on the upper lid covering the eye ball, shadow below the brow, and transition down to the cheek. If those forms read correctly, even a bare-bones eye can appear convincing. This is a more valuable check-point than noting how much detail is present on the page.
