lens eye

The lens of the eye is a transparent, biconvex structure located behind the iris. Its primary function is to focus light onto the retina, allowing for clear vision. The lens achieves this by changing its shape, a process called accommodation, which enables the eye to focus on objects at varying distances. This ability diminishes with age, leading to presbyopia. Clouding of the lens, known as a cataract, can impair vision and is often correctable with surgery.1

Lens eyes are a type of single-chambered eye, distinguished by their use of a lens to focus light. This contrasts with compound eyes, which use multiple lenses. The lens's ability to form a focused image is crucial for vision, and its optical properties have evolved in diverse ways across the animal kingdom to optimize light capture and image formation in different environments. The human eye's optical system involves refraction at four surfaces: the anterior and posterior surfaces of the cornea and the crystalline lens, all working together to focus light onto the retina.23