01:830:301 Lecture Notes - Lecture 5: Refractive Error, Optic Disc, Visual Acuity
2 May 2016
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Document Summary
Lens in the eye refracts light to focus the image on the retina. Accommodation- process in which the lens changes its shape, thus altering its refractive power and focusing on different focal planes in the outside world. The image is properly focused on the retina. Myopia- lens focuses in front of the eye instead of on the retina (nearsighted) Myopia with correction- glasses fixes how the light reflects. It pulls the light further apart so it reflects to the right spot. Hyperopia- light focuses behind the retina (the opposite of myopia). Astigmatism- visual defect caused by the unequal curving of one or more of the refractive surfaces of the eye, usually the cornea. Presbyopia ( old sight )- condition of being unable to accommodate the lens sufficiently to focus on the nearby objects. Caused by sclerosis (hardening of lens) and loss of elasticity of the tissue that moves the lens.
