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Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation. Because of the paralysis of the ciliary muscle, the curvature of the lens can no longer be adjusted to focus on nearby objects. This results in similar problems as those caused by presbyopia, in which the lens has lost elasticity and can also no longer focus on close-by objects. Cycloplegia with accompanying mydriasis (dilation of pupil) is usually due to topical application of muscarinic antagonists such as atropine and cyclopentolate. ==Anatomy== The iris is the heavily pigmented coloured part of the eye. It has a contractile diaphragm in front of the lens with a central opening called the pupil. It is located between the lens and the cornea, and is attached radially to the ciliary body and the cornea via ligaments called pectinate ligaments. The iris contains two sets of muscles: * a radial group for enlargement of the pupil (dilator pupillae) * a circular group set to decrease pupil size on contraction (sphincter pupillae). The muscles regulate the amount of light entering the eye. The sphincter pupillae is stimulated through muscarinic receptors by the parasympathetic nervous system. The dilator pupillae is stimulated through noradrenergic receptors by the sympathetic nervous system. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「cycloplegia」の詳細全文を読む スポンサード リンク
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