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
Presbyopia is a physiological insufficiency of optical Accommodation (vertebrate eye), accommodation associated with the aging of the human eye, eye; it results in progressively worsening ability to focus clearly on close objects. Also known as ...
, 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
Cyclopentolate is a muscarinic antagonist. It is commonly used as an eye drop during pediatric eye examinations to dilate the eye (mydriatic) and prevent the eye from focusing/Accommodation (eye), accommodating (cycloplegia, cycloplegic). Cyclop ...
.
Belladonna alkaloids are used for testing the error of
refraction
In physics, refraction is the redirection of a wave as it passes from one transmission medium, medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commo ...
and examination of eye.
Management
Cycloplegic drugs are generally
muscarinic receptor antagonists such as
atropine,
cyclopentolate
Cyclopentolate is a muscarinic antagonist. It is commonly used as an eye drop during pediatric eye examinations to dilate the eye (mydriatic) and prevent the eye from focusing/Accommodation (eye), accommodating (cycloplegia, cycloplegic). Cyclop ...
,
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 eye) and the treatment of
uveitis. All cycloplegics are also
mydriatic (pupil dilating) agents and are used as such during
eye examination to better visualize the
retina
The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...
.
When cycloplegic drugs are used as a mydriatic 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. The ones specifically 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
Anisocoria is a condition characterized by an unequal size of the eyes' pupils. Affecting up to 20% of the population, anisocoria is often entirely harmless, but can be a sign of more serious medical problems.
Causes
Anisocoria is a common cond ...
*
Marcus Gunn pupil
*
*
Parinaud's syndrome
*
Syphilis
Syphilis () is a sexually transmitted infection caused by the bacterium ''Treponema pallidum'' subspecies ''pallidum''. The signs and symptoms depend on the stage it presents: primary, secondary, latent syphilis, latent or tertiary. The prim ...
References
External links
*
*
{{Mydriatics and cycloplegics
Diagnostic ophthalmology
Disorders of ocular muscles, binocular movement, accommodation and refraction