Focusing via Visual Accommodation

Learning objectives

To understand that accommodation is the result of the ability of the lens to adjust in order to keep objects focused on the retina, and that this ability has limits.

By changing its curvature, the eye’s lens causes light rays to converge so that they focus on the retina – a process known as accommodation. You can observe this by dragging the candle along the optic axis. This focusing is only possible beyond a limit called the "punctum proximum" or "near point". Otherwise, the image is formed behind the retina and so is blurre.

The diagram is not drawn to scale!