The shape of the pupil appears circular when viewed directly, but elliptical when viewed at an angle.
Pupil Shape Explained
The pupil, the opening in the center of the iris, controls the amount of light that enters the eye. Its shape isn't always perceived consistently. Here's a breakdown:
- On-Axis View: From a direct, head-on perspective, the pupil appears circular in shape.
- Off-Axis View: When viewed at an angle, the pupil's shape appears elliptical. The more extreme the angle, the more elongated the ellipse seems. This is because the pupil, being a physical opening within a 3D structure (the eye), is subject to perspective.
| Viewing Angle | Perceived Pupil Shape |
|---|---|
| Direct (On-Axis) | Circular |
| Angled (Off-Axis) | Elliptical |
This change in apparent shape is purely an optical effect, similar to how a perfectly circular plate looks elliptical when tilted away from you. The actual physical shape of the pupil remains circular.
