Cycloplegia

Cycloplegia
Classification and external resources
Cycloplegia caused by Cyclopentolate 1% instilled into both eyes
ICD-10	H52.5
ICD-9	367.51
DiseasesDB	17379

Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation.^[1]

Anatomy

The iris is the heavily pigmented colored 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.

Photophobia

Destruction of the sphincter pupillae from any cause can result in permanent photophobia. Light entering an eye with a destroyed sphincter will result in pain, because the pupil can not constrict.

Cycloplegic drugs

Cycloplegic drugs are generally muscarinic receptor blockers. These include atropine, cyclopentolate, homatropine, scopolamine and tropicamide. They are indicated for use in cycloplegic refraction (to paralyze the ciliary muscle in order to determine the true refractive error of the lens) and the treatment of uveitis. Many cycloplegics are also mydriatic (pupil dilating) agents and are used as such during ophthalmoscopic examinations to better visualize the retina.

When cycloplegic drugs are used to dilate the pupil, the pupil in the normal eye regains its function when the drugs are metabolized or carried away. Some cycloplegic drugs can cause dilation of the pupil for several days. Usually the ones used by ophthalmologists or optometrists wear off in hours, but when the patient leaves the office strong sunglasses are provided for comfort.

See also

• Adie syndrome
• Anisocoria
• Marcus Gunn pupil
• Miosis
• Parinaud's syndrome
• Syphilis

References

1. ^ "cycloplegia" at Dorland's Medical Dictionary

This medical sign article is a stub. You can help Wikipedia by expanding it.v · Categories: Disorders of ocular muscles, binocular movement, accommodation and refraction Medical sign stubs Wikimedia Foundation. 2010. Игры ⚽ Поможем решить контрольную работу Vega (launcher) Hot rod Look at other dictionaries: cycloplegia — [sī΄klōplē′jē ə, sī΄klō plējə] n. [ModL < CYCLO + PLEGIA] paralysis of those muscles of the eye responsible for visual accommodation cycloplegic [sī΄klō plējik] adj …   English World dictionary cycloplegia — cycloplegic, adj., n. /suy kleuh plee jee euh, jeuh, sik leuh /, n. Pathol. paralysis of the intraocular muscles. [1900 05; CYCLO + PLEGIA] * * * …   Universalium cycloplegia — noun paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation See Also: cycloplegic …   Wiktionary cycloplegia — Loss of power in the ciliary muscle of the eye; may be by denervation or by pharmacologic action. [cyclo + G. plege, stroke] * * * cy·clo·ple·gia .sī klō plē j(ē )ə, .sik lō n paralysis of the ciliary muscle of the eye * * * n. paralysis of the… …   Medical dictionary cycloplegia — n. paralysis of the ciliary eye muscle …   English contemporary dictionary cycloplegia — cy·clo·ple·gia …   English syllables cycloplegia — n. paralysis of the ciliary muscle of the eye (see ciliary body). This causes inability to alter the focus of the eye and is usually accompanied by paralysis of the muscles of the iris, resulting in fixed dilation of the pupil (mydriasis). It is… …   The new mediacal dictionary cycloplegia — /ˌsaɪkloʊˈplidʒə/ (say .suykloh pleejuh), /ˌsɪkloʊ / (say .sikloh ) noun paralysis of the intra ocular muscles …   cycloplegia —   n. paralysis of ciliary muscle.    ♦ cycloplegic, a …   Dictionary of difficult words cycloplegia — ˌ ̷ ̷ ̷ ̷ at cyclo +ˈplēj(ē)ə noun ( s) Etymology: New Latin, from cycl + plegia : paralysis of the ciliary muscle of the eye …   Useful english dictionary 18+ © Academic, 2000-2024 Contact us: Technical Support, Advertising Dictionaries export, created on PHP, Joomla, Drupal, WordPress, MODx. Mark and share Search through all dictionaries Translate… Search Internet Share the article and excerpts Direct link … Do a right-click on the link above and select “Copy Link”