a) The Lens:
The lens of the eye is transparent and flexible, allowing it to focus light onto the retina.
Its shape can be adjusted by the ciliary muscles, enabling the eye to focus on objects at different distances, a process called accommodation.
Its transparency allows light to pass through without scattering, ensuring a clear image is formed on the retina.
b) Sclera:
The sclera is the tough, fibrous outer layer of the eye that provides protection and structural support.
It maintains the shape of the eye, preventing it from collapsing under pressure.
It also serves as an attachment point for the extraocular muscles, which control eye movement.
c) Iris:
The iris is the colored part of the eye and is responsible for regulating the amount of light that enters the eye.
It contains muscles that control the size of the pupil, which adjusts in response to the brightness of the environment.
In bright conditions, the iris contracts to reduce the size of the pupil, limiting the amount of light entering the eye. In dim conditions, the iris dilates to enlarge the pupil, allowing more light to enter.
d) Choroid:
The choroid is a highly vascular layer located between the sclera and the retina.
It supplies oxygen and nutrients to the retina, helping to maintain its function.
The dark pigment in the choroid absorbs excess light, preventing it from scattering within the eye and reducing glare.
It also helps to regulate the temperature of the eye, ensuring that it remains within a suitable range for optimal function.
