Lens nucleus

Lens nucleus is the central, densest part of the eye lens, which is responsible for focusing light onto the retina. The lens nucleus is surrounded by the softer cortex and is made up of long-lived lens fiber cells.

Structure

The lens nucleus is composed of tightly packed, elongated, and transparent lens fiber cells. These cells are unique in that they do not contain any organelles or nuclei, which allows for the maximum transmission of light. The lens nucleus is the oldest part of the lens, with the cells being formed prenatally and persisting throughout life.

Function

The primary function of the lens nucleus is to focus light onto the retina. It does this by refracting, or bending, the light that enters the eye. The shape of the lens nucleus, along with the surrounding cortex, determines the degree of this refraction. The lens nucleus is also responsible for the eye's ability to adjust its focus from distant to near objects, a process known as accommodation.

Clinical significance

Changes in the lens nucleus can lead to vision problems. For example, nuclear sclerosis is a condition in which the lens nucleus becomes hard and cloudy, leading to a gradual loss of vision. This is a common form of cataract, which is a leading cause of blindness worldwide. Other conditions that can affect the lens nucleus include nuclear cataract and presbyopia, both of which are associated with aging.

See also

• Lens (anatomy)
• Cataract
• Presbyopia