Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation. Cycloplegia with accompanying mydriasis (dilation of pupil) is usually due to topical application of muscarinic antagonists such as atropine and cyclopentolate.
Cycloplegic agents are indicated to reduce pain and prevent posterior synechiae in patients with suppurative keratitis or endophthalmitis.
A muscarinic receptor antagonist used to dilate the pupil. An anticholinergic used to cause mydriasis and cycloplegia for diagnostic testing. An alpha and beta-adrenergic agonist indicated to treat hypotension under anesthesia, allergic conditions, bronchial asthma, and nasal congestion.
A cycloplegic eye drop is an eye drop that temporarily paralyzes the ciliary body, allowing a doctor to fully measure a patient’s vision problem. When the ciliary body is paralyzed, the eye cannot focus on near or intermediate objects at all. As a result, the true refractive error can be measured.
Miotic agents (parasympathomimetics) Miotics work by contraction of the ciliary muscle, tightening the trabecular meshwork and allowing increased outflow of aqueous through traditional pathways. Miosis results from action of these drugs on the pupillary sphincter.
Tropicamide, as an alternative, is a synthetic analog of tropic acid and is known as a safe agent for cycloplegic refraction. It characterized by a rapid onset and the cycloplegia effect appears 20–30 min after administration.
There are known side effects associated with cycloplegic agents. Reported cases of systemic side effects of these include acute midbrain hemorrhage, ataxia, restlessness, hallucinations, seizures, fever, dryness of the mouth and skin, tachycardia, delirium, and death.
These drops help the doctor examine the back of the eye. Dilating the pupil can also help to reduce inflammation and discomfort in the eye after surgery or injury, or treat inflammation which occurs in certain conditions. They can also be used to help treat amblyopia (‘lazy’ eye).
Topical mydriatics are used during an eye examination to allow visualization of the retina and other structures deep within the eye. Mydriatics may also be used to treat inflammatory eye conditions such as iritis and cyclitis and to reduce cycloplegia (a painful paralysis of the ciliary muscle of the eye).
A mydriatic is an agent that induces dilation of the pupil. Drugs such as tropicamide are used in medicine to permit examination of the retina and other deep structures of the eye, and also to reduce painful ciliary muscle spasm (see cycloplegia).
Miosis, or myosis, is excessive constriction of the pupil. The term is from Ancient Greek μύειν mūein, “to close the eyes”. The opposite condition, mydriasis, is the dilation of the pupil. Anisocoria is the condition of one pupil being more dilated than the other.
Topical atropine is used as a cycloplegic, to temporarily paralyze the accommodation reflex, and as a mydriatic, to dilate the pupils.
Effects generally may last for up to 24 hours, but may last several days in some people. People with dark eye colors may require increased cyclopentolate doses.
Cyclopentolate is contraindicated for use in patients with untreated narrow angle glaucoma (closed-angle glaucoma ). Use cautiously in those with Down’s Syndrome and in those predisposed to increases in intraocular pressure. Cyclopentolate contains benzalkonium chloride, which may be absorbed by contact lenses.
Mydriasis is the medical term for an unusual dilation or widening of the pupils. Normally, a person’s pupils dilate when the light is dim so that more light can enter the eye. Mydriasis describes a condition where the pupils dilate without a change in the levels of light.