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Retinal hemorrhage (UK English: retinal haemorrhage) is a disorder of the eye in which bleeding occurs in the retina, the light sensitive tissue, located on the back wall of the eye. [ 1] There are photoreceptor cells in the retina called rods and cones, which transduce light energy into nerve signals that can be processed by the brain to form ...
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. It is approximately spherical in shape, with its outer ...
Flash blindness is caused by bleaching (oversaturation) of the retinal pigment. [ 2] As the pigment returns to normal, so too does sight. In daylight the eye's pupil constricts, thus reducing the amount of light entering after a flash. At night, the dark-adapted pupil is wide open, so flash blindness has a greater effect and lasts longer.
Blinking. Blinking. Blinking is a bodily function; it is a semi-autonomic rapid closing of the eyelid. [1] A single blink is determined by the forceful closing of the eyelid or inactivation of the levator palpebrae superioris and the activation of the palpebral portion of the orbicularis oculi, not the full open and close. [citation needed]
Raccoon eyes. Raccoon eyes, also known as panda eyes or periorbital ecchymosis, is a sign of basal skull fracture or subgaleal hematoma, a craniotomy that ruptured the meninges, or (rarely) certain cancers. [1] [2] Bilateral hemorrhage occurs when damage at the time of a facial fracture tears the meninges and causes the venous sinuses to bleed ...
An afterimage is an image that continues to appear in the eyes after a period of exposure to the original image. An afterimage may be a normal phenomenon (physiological afterimage) or may be pathological ( palinopsia ). Illusory palinopsia may be a pathological exaggeration of physiological afterimages. Afterimages occur because photochemical ...
Retinal regeneration refers to the restoration of vision in vertebrates that have suffered retinal lesions or retinal degeneration. The two most well-studied mechanisms of retinal regeneration are cell-mediated regeneration and cellular transplantation. Regenerative processes may have applications in humans for treating degenerative retinal ...
The ocular immune system protects the eye from infection and regulates healing processes following injuries. The interior of the eye lacks lymph vessels but is highly vascularized, and many immune cells reside in the uvea, including mostly macrophages, dendritic cells, and mast cells. [1] These cells fight off intraocular infections, and ...