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  2. Sclera - Wikipedia

    en.wikipedia.org/wiki/Sclera

    The sclera's blood vessels are mainly on the surface. Along with the vessels of the conjunctiva (which is a thin layer covering the sclera), those in the episclera render the inflamed eye bright red. [6] In many vertebrates, the sclera is reinforced with plates of cartilage or bone, together forming a circular structure called the sclerotic ring.

  3. Human eye - Wikipedia

    en.wikipedia.org/wiki/Human_eye

    Amber eye. Amber eyes are a solid color with a strong yellowish/golden and russet/coppery tint, which may be due to the yellow pigment called lipochrome (also found in green eyes). [38] [39] Amber eyes should not be confused with hazel eyes. Although hazel eyes may contain specks of amber or gold, they usually tend to have many other colors ...

  4. Chromatophore - Wikipedia

    en.wikipedia.org/wiki/Chromatophore

    It is packaged in vesicles called melanosomes and distributed throughout the cell. Eumelanin is generated from tyrosine in a series of catalysed chemical reactions. It is a complex chemical containing units of dihydroxyindole and dihydroxyindole-2-carboxylic acid with some pyrrole rings. [12] The key enzyme in melanin synthesis is tyrosinase ...

  5. Visual system - Wikipedia

    en.wikipedia.org/wiki/Visual_system

    The neuropsychological side of visual information processing is known as visual perception, an abnormality of which is called visual impairment, and a complete absence of which is called blindness. The visual system also has several non-image forming visual functions, independent of visual perception, including the pupillary light reflex and ...

  6. Biological pigment - Wikipedia

    en.wikipedia.org/wiki/Biological_pigment

    These cells are usually located beneath the skin or scale the animals. There are two categories of colors generated by the cell – biochromes and schematochromes. Biochromes are colors chemically formed microscopic, natural pigments. Their chemical composition is created to take in some color of light and reflect the rest.

  7. Evolution of the eye - Wikipedia

    en.wikipedia.org/wiki/Evolution_of_the_eye

    The human eye, showing the iris and pupil. In 1802, philosopher William Paley called it a miracle of "design."In 1859, Charles Darwin himself wrote in his Origin of Species, that the evolution of the eye by natural selection seemed at first glance "absurd in the highest possible degree". [3]

  8. On Vision and Colours - Wikipedia

    en.wikipedia.org/wiki/On_Vision_and_Colours

    Colors and the laws by which they appear reside within the eye. The external cause of color is a stimulus which excites the retina and separates its polarity. Goethe had organized color into three classes: physiological, physical, and chemical. He proposed that the external causes of color are physical colors and chemical colors. [16] [17]

  9. Retina - Wikipedia

    en.wikipedia.org/wiki/Retina

    The retina (from Latin rete 'net'; pl. retinae or retinas) is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs.The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception.