Eyeball: Structure and Layers

The human eyeball is a complex organ responsible for vision. It consists of multiple layers that work together to process light and generate images.

Structure of the Eyeball

The eyeball is a spherical structure located in the orbital cavity of the skull, protected by the eyelids and surrounded by various supportive tissues.

Key Components:

• Cornea: Transparent outer layer that refracts light.
• Aqueous Humor: Fluid-filled space that maintains intraocular pressure.
• Iris & Pupil: Regulate the amount of light entering the eye.
• Lens: Focuses light onto the retina.
• Vitreous Body: Gel-like substance supporting the eyeball.
• Retina: Light-sensitive layer that converts light into neural signals.
• Optic Nerve: Transmits visual information to the brain.

Layers of the Eyeball

The eyeball is composed of three distinct layers:

1. Fibrous Layer

The outermost protective layer, consisting of the cornea and sclera.

2. Vascular Layer (Uvea)

• Choroid: Provides nourishment through blood vessels.
• Ciliary Body: Adjusts lens shape and produces aqueous humor.
• Iris: Controls pupil size and light intake.

3. Neural Layer (Retina)

The innermost layer containing photoreceptors:

• Rods: Sensitive to low-light conditions.
• Cones: Responsible for color vision.