The human eye is a sensory organ and a component of the sensory nervous system. It responds to visible light and enables us to use visual information for a variety of functions, including as seeing objects, maintaining balance, and regulating our circadian rhythm.
An optical instrument that is alive might be thought of as the eye. Its outer layers, including the outermost, white component of the eye (the sclera) and one of its inner layers (the pigmented choroid), make the eye essentially light-tight, with the exception of the optic axis.

Human eye

by University of Dundee

Human eye

by University of Dundee

The human eye is a sensory organ and a component of the sensory nervous system. It responds to visible light and enables us to use visual information for a variety of functions, including as seeing objects, maintaining balance, and regulating our circadian rhythm.
An optical instrument that is alive might be thought of as the eye. Its outer layers, including the outermost, white component of the eye (the sclera) and one of its inner layers (the pigmented choroid), make the eye essentially light-tight, with the exception of the optic axis.

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