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The macula (/ˈmakjʊlə/) [1] or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around 5.5 mm (0.22 in) and is subdivided into the umbo, foveola, foveal avascular zone, fovea, parafovea, and perifovea areas.
The human eye is a sensory organ in the visual system that reacts to visible light allowing eyesight. Other functions include maintaining the circadian rhythm, and keeping balance. Arizona Eye Model. "A" is accommodation in diopters. The eye can be considered as a living optical device.
Several layers such as the neural tube, neural crest, surface ectoderm, and mesoderm contribute to the development of the eye. [2] [3] [4] Eye development is initiated by the master control gene PAX6, a homeobox gene with known homologues in humans (aniridia), mice (small eye), and Drosophila (eyeless). The PAX6 gene locus is a transcription ...
contralateral frontal eye field of the middle frontal gyrus of the frontal lobe (via frontopontine fibers [6] The frontal eye field meanwhile receives afferents from the visual cortex. [7] superior colliculus [6] vestibular nuclei [6] other parts of the reticular formation. [6]
Brodmann area 8. The frontal eye fields (FEF) are a region located in the frontal cortex, more specifically in Brodmann area 8 or BA8, [1] of the primate brain.In humans, it can be more accurately said to lie in a region around the intersection of the middle frontal gyrus with the precentral gyrus, consisting of a frontal and parietal portion. [2]
With this simple geometrical similarity, based on the laws of optics, the eye functions as a transducer, as does a CCD camera. In the visual system, retinal , technically called retinene 1 or "retinaldehyde", is a light-sensitive molecule found in the rods and cones of the retina .
There are about 0.7 to 1.5 million retinal ganglion cells in the human retina. [2] With about 4.6 million cone cells and 92 million rod cells, or 96.6 million photoreceptors per retina, [3] on average each retinal ganglion cell receives inputs from about 100 rods and cones.
There are two important foramina, or windows, two important fissures, or grooves, and one canal surrounding the globe in the orbit. There is a supraorbital foramen, an infraorbital foramen, a superior orbital fissure, an inferior orbital fissure and the optic canal, each of which contains structures that are crucial to normal eye functioning.