Human Eye Structure and Function

Structure of the Eye:
- Cornea: Transparent outer layer that refracts light.
- Pupil: Opening that controls light entry; size adjusts based on light conditions.
- Iris: Colored part of the eye; regulates pupil size.
- Lens: Focuses light onto the retina; can change shape (accommodation).
- Retina: Layer of light-sensitive cells (rods and cones) that converts light into neural signals.
- Optic Nerve: Transmits visual information from the retina to the brain.
Functioning of the Eye:
- Light enters through the cornea and pupil, is focused by the lens, and hits the retina.
- Rods detect light intensity (black and white vision); cones detect colors.
- Image is inverted on the retina; the brain processes it to produce an upright image.
Common Eye Conditions:
- Myopia (Nearsightedness): Difficulty seeing distant objects due to elongated eyeball.
- Hyperopia (Farsightedness): Difficulty seeing close objects due to shortened eyeball.
- Astigmatism: Distorted vision caused by an irregularly shaped cornea or lens.
- Presbyopia: Age-related difficulty in focusing on nearby objects.

Nature of Light:
- Light is electromagnetic radiation visible to the human eye.
- Composed of different wavelengths corresponding to different colors (red, orange, yellow, green, blue, indigo, violet).
Color Perception:
- Additive Color Mixing: Combination of different colors of light (RGB model); used in screens and lighting.
- Subtractive Color Mixing: Combination of pigments (CMY model); used in painting and printing.
Color and Objects:
- Objects appear colored based on the wavelengths they reflect; for example, a red apple reflects red light and absorbs other wavelengths.
- White light contains all colors; when it hits a prism, it refracts and separates into a spectrum.
Psychological Effects of Color:
- Different colors can evoke various emotions and responses (e.g., blue can be calming, red can be energizing).
- Cultural significance can also influence color perception and meanings.
Applications of Color:
- Used in art, design, branding, and psychology to evoke feelings and communicate messages.

Cornea: The eye's transparent outer layer responsible for light refraction.
Pupil: An adjustable opening that regulates light entry based on illumination levels.
Iris: The colored segment that controls pupil size.
Lens: A flexible structure that focuses light onto the retina, enabling accommodation.
Retina: Contains rods and cones; it is responsible for converting light into neural signals.
Optic Nerve: The pathway that carries visual information from the retina to the brain.
Light Pathway: Light enters through the cornea and pupil, is focused by the lens, and activates the retina.
Rods and Cones: Rods are sensitive to light intensity, facilitating black and white vision; cones are responsible for color detection.
Image Processing: Images are inverted on the retina, with the brain interpreting them as upright.
Myopia (Nearsightedness): A vision condition where distant objects appear blurry due to an elongated eyeball.
Hyperopia (Farsightedness): A condition characterized by difficulty seeing close objects, typically caused by a shortened eyeball.
Astigmatism: Distorted vision results from an irregularly shaped cornea or lens.
Presbyopia: Age-related vision impairment, leading to trouble focusing on nearby objects.

Nature of Light: Light is electromagnetic radiation detectable by the human eye.
Color Wavelengths: Light comprises varied wavelengths that correspond to specific colors (e.g., red, orange, yellow, green, blue, indigo, violet).
Additive Color Mixing: Involves combining different light colors (RGB model) prevalent in screens and lighting.
Subtractive Color Mixing: The blending of pigments (CMY model), commonly used in art and printing processes.
Color Perception: Object color derives from wavelengths they reflect; for instance, a red apple reflects red light and absorbs other wavelengths.
White Light Spectrum: White light encompasses all colors; when refracted through a prism, it separates into a spectrum of hues.
Psychological Effects: Different colors can elicit various emotional responses; blue may promote calmness while red can energize.
Cultural Influences: Perception of colors and their meanings can vary significantly across different cultures.
Applications of Color: Employed in art, design, branding, and psychology to evoke feelings and convey messages effectively.