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This text discusses how to depict an eye either from the side (profile) or from the front. The opening of the eye (assuming it looks straight ahead) is determined by the height of the pupil which the eyelid slightly covers at the top. In this position, the eyelashes are directed towards a point (r) appearing higher and more to the right than the center of the circle that outlines the eye's globe. In nature, eyelashes point towards the center of the globe, but when drawing, one only considers the surfaces. Notably, the point where the eyelashes converge seems to change based on the eye's position relative to the observer.

Figure 6 shows an eye viewed at a regular three-quarter angle. Here, the pupil appears less aside compared to a smaller three-quarter view but not yet in the middle. The pupil and iris are not entirely round yet: the caruncle appears more prominently, and on the smaller side, a large part of the upper eyelid's edge thickness is visible.

Next is the eye from a lost profile view. The pupil is so foreshortened it is barely visible, and thus, the iris is not seen. Figure 13 clearly demonstrates this position where the eye and therefore the head are so turned that, if one saw the whole eyeball, the attachment of the optical nerve would be visible. From this position, it follows that 1) the width of the eyeball seen in profile (a, b, fig. 4) equals half the width of the nose or a quarter of a part; here, AB signifies a nose width belonging to these eyes, or half of a part; 2) the eyeball's width, seen from a small three-quarter angle (c, d, fig. 5), equals half the nose's width; 3) from a regular three-quarter view (e, f, fig. 6), equals three-quarters of the nose's width; 4) when viewed from the front (i, h, fig. 7), it equals the entire nose width; 5) in lost profile (diameter k l, fig. 678), it equals a quarter of the nose's width or a part. Recall that the nose's width, whether in profile, face, or three-quarters, always equals half its height or half a part.

Figures 9, 10, 11, and 12 show eyes looking upward. In this position, the muscle located in the upper part of the eyeball contracts, making it turn: thus, the pupil initially in the eye's opening center moves upward; the more the muscle contracts, consequently, the more the globe turns upward, and the top of the pupil is further hidden by the upper eyelid. Less of the pupil is seen in fig. 12 than in fig. 9, whose gaze is aimed obliquely. Here, the upper eyelid appears more arched, and the lower eyelid nearly straight: only a small part of the upper eyelid's lower edge thickness is seen, less than when viewed from the front. Figures 14, 15, 16 show eyes looking downward. The muscle positioned in the lower part of the eyeball contracts, turning the globe downward, directing the pupil towards the ground. The lower eyelid elongates as the upper eyelid travels back over a shorter distance than when looking upward. When closing the eye partly, the lower lid covers one-third of the visible eyeball, with the upper lid covering two-thirds.

In eyes looking down (figs. 14, 15, 16), the lower eyelid's thickness is visible, but not the upper eyelid's thickness. When drawing an eye looking up, the lashes converge at the upper eyelid's curve center. This center varies to the side, depending on whether viewing the eye in profile, three-quarters, or frontally. In figures 9, 10, 11, 12, 13, this point is marked by an A. In lowered eyes, this point is marked by an a. Figure 17 depicts a closed eye, with lashes directed to point a. Figure 19 shows an eye viewed from the front, looking sideways. In this case, the orbit and eye covers are seen from the front, but the muscle on the left side of the globe contracts, turning the globe on itself, placing the pupil to the left.

Translation Notes:

• Lost profile: a somewhat archaic term here used to describe a view of the eye where its profile is hard to discern.
• Caruncle: refers to the small, pink, globular nodule at the inner corner of the eye.