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Eye - Diseases disorders and age-related changes

Eye - Diseases disorders and age-related changes: Encyclopedia II - Eye - Diseases disorders and age-related changes

There are many diseases and disorders that may affect the eyes. As the eye ages certain changes occur that can be attributed to solely the aging process. Most of these anatomic and physiologic processes follow a gradual decline. With aging, the quality of vision worsens due to reasons independent of aging eye diseases. While there are many changes of significance in the nondiseased eye, the most functionally important changes seem to be a reduction in pupil size and the loss of accommodation or focusing capability (presbyopia). The ar ...

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Eye, Eye - Accommodation, Eye - Acuity, Eye - Adnexa and related parts, Eye - Anatomy, Eye - Cytology, Eye - Diseases disorders and age-related changes, Eye - Dynamic range, Eye - Evolution of eyes, Eye - Eye movement, Eye - Eyebrows, Eye - Eyelashes, Eye - Eyelids, Eye - Microsaccades, Eye - Optokinetic reflex, Eye - Rapid eye movement, Eye - Saccades, Eye - Smooth pursuit movement, Eye - The orbit, Eye - Varieties of eyes, Eye - Vergence movement, Eye - Vestibulo-ocular reflex, WikiSaurus:eye — the WikiSaurus list of synonyms and slang words for eyes in many languages, Adaptation, Binocular vision, Corrective lens, Crystallin, Evil eye, Eye color, Eye contact, Eye tracking, Eyeglass prescription, Macropsia, Micropsia, Nictitating membrane, Ocular tremor, Ophthalmology, Optician, Optometry, Persistence of vision, Phosphenes, Snellen chart, Staring contest, Tears, Visual perception

Eye: Encyclopedia II - Eye - Diseases disorders and age-related changes

Eye - Diseases disorders and age-related changes

Main articles: List of eye diseases and disorders, and Ocular manifestations of systemic disease, and [[{{{3}}}]], and [[{{{4}}}]], and [[{{{5}}}]]

There are many diseases and disorders that may affect the eyes.

As the eye ages certain changes occur that can be attributed to solely the aging process. Most of these anatomic and physiologic processes follow a gradual decline. With aging, the quality of vision worsens due to reasons independent of aging eye diseases. While there are many changes of significance in the nondiseased eye, the most functionally important changes seem to be a reduction in pupil size and the loss of accommodation or focusing capability (presbyopia). The area of the pupil governs the amount of light that can reach the retina. The extent to which the pupil dilates also decreases with age. Because of the smaller pupil size, older eyes receive much less light at the retina. In comparison to younger people, it is as though older persons wear medium-density sunglasses in bright light and extremely dark glasses in dim light. Therefore, for any detailed visually guided tasks on which performance varies with illumination, older person requires extra lighting. ^[3]

With aging a prominent white ring develops in the periphery of the cornea- called arcus senilis. Aging causes laxity and downward shift of eyelid tissues and atrophy of the orbital fat. These changes contribute to the etiology of several eyelid disorders such as ectropion, entropion, dermatochalasis,and ptosis. The vitreous gel undergoes liquefaction (posterior vitreous detachment or PVD) and its opacities - visible as floaters gradually increase in number.

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Accommodation (eye), Adaptation, Anterior chamber, Aqueous humour, Binocular vision, Blind spot, Blinking, Choroid, Ciliary body, Ciliary muscle, Compound eyes, Conjunctiva, Cornea, Corrective lens, Crystallin, Crystalline Lens, David Berlinski, Evil eye, Extraocular muscles, Eye color, Eye contact, Eye movements, Eye tracking, Eyeglass prescription, Fovea, Iris, Lens, List of eye diseases and disorders, Macropsia, Macula, Micropsia, Microsaccade, Nautilus, Nictitating membrane, Ocular manifestations of systemic disease, Ocular tremor, Ophthalmology, Optic disc, Optic nerve, Optician, Optometry, Ora serrata, Origin of Species, Persistence of vision, Phosphenes, Pinhole Camera, Pupil, Purkinje effect, Rapid eye movement, Retina, Saccade, Schlemm's canal, Sclera, Snellen chart, Staring contest, Strepsiptera, Suspensory ligament, Tapetum lucidum, Tears, Trabecular meshwork, Trilobites, Vestibulo-ocular reflex, Visual acuity, Visual perception, Vitreous humour, WikiSaurus, action potential, amphibians, angular resolution, aqueous humour, arthropods, astigmatism, astronomers, bacterial infection, binocular vision, bipolar cell, birds, birds of prey, blind spot, blood vessels, brain, camera, cell membrane, cephalopods, chameleons, chemical, choroid, chromatic aberration, ciliary body, ciliary muscles, colour vision, cone cells, cones, connective tissue, contrast ratio, converge, convergence, convex, cornea, corneal endothelium, crystallins, degree, diopter, diurnal, divergence, ears, electromagnetic radiation, evolution, eyebrows, eyelashes, eyelids, f-number, feedback, fibrin, fish, focus, fovea, ganglion cell, hertz, humans, hyperopia, immune system, inferior oblique, inferior rectus, intelligent design, invertebrates, ion channels, iris, lateral rectus, lens, light, mammals, medial rectus, mollusks, monophyletic, moulting, myopia, nerve impulses, ocelli, opsin, optic nerve, orbits, organ, organisms, osmotic, oxygen, parallel evolution, photopsin, photoreceptor, photosensitive, presbyopia, primary colours, proteins, pupil, rabbits, reading, red, green and blue, refraction errors, refractive index, reptiles, respiration, retina, retinal, rhodopsin, rod, rods, sclera, secondary colours, sense, sleep, snails, snakes, squids, stemmata, stops, superior oblique, superior rectus, suspensory ligaments, synapse, tapetum lucidum, three-dimensional, transmitter molecules, transparent, ultraviolet, vertebrates, vision, visual acuity, visual cortex, vitreous humour, wavelengths, yellow

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