Intercanthal-to-eye width ratio

The eye openings provide a nearby scale for the space between them. A gap can look modest beside long eyes and more expansive beside short ones, even when the inner corners stay at the same distance.

It differs from pupil spacing relative to the cheeks. Short eyes around a wide-looking gap can occupy little total facial width. Long eyes around a smaller relative gap can spread the pupils across much of the face. Looking at both comparisons separates local spacing from the size of the whole eye region.

Moving the inner corners farther apart raises the ratio by increasing the gap. More space appears between the openings, which can make their separation conspicuous. If the eyes also span much of the face, the wide-set impression is visible against the cheeks as well.

Shortening the openings raises the ratio without widening the gap. The space looks larger beside smaller eyes, while the inner corners can remain in place. A high ratio in this setting is better explained by eye length than by assuming the eyes have moved apart.

At a low ratio, closer inner corners reduce the gap, while longer openings make an unchanged gap relatively smaller. Inspect both eyes separately because their average width can conceal a longer opening on one side.

The nasal base supplies another span directly below the inner-eye gap. A broad gap above a narrow base creates more space around the upper nose. A small gap above a broader base makes the nasal wings extend beyond the inner-eye lines, even if the nose is modest within the face.

Nose-to-face width helps distinguish those cases. If the nose is broad against the cheeks too, nasal size contributes more to the contrast. If its facial share is modest, a narrow eye gap may explain why it looks broad locally.

These ratios move together when they share a distance. Widening the gap raises gap-to-eye width and lowers nose-to-gap width while the eye openings and nasal base stay unchanged. They describe the same extra space rather than separate anatomical changes.

The traditional reference places an eye-width gap between the openings. The 0.95–1.05 interval describes approximate equality, making the arrangement easy to picture. Attractive-model studies have also found longer eyes relative to the gap, so equal spacing is not a requirement of an attractive eye region.

Naran and colleagues altered spacing in 16 female faces and collected ratings from 490 observers. A modest increase in intercanthal distance improved ratings among the tested versions.

The gap and eye openings develop at different rates, so their ratio can change as the eye region grows. Population differences in these dimensions also affect which relationships are common in a reference sample.

Adult eyelid studies have documented shorter horizontal openings with age. That can make the gap-to-eye ratio rise even if the inner corners remain the same distance apart. Comparable earlier photographs help distinguish widening of the gap from shortening of the openings.