Ciliary muscle spasm

Treatment of Uveitis. Atropine is extremely useful in the treatment of anterior uveal inflammation. Atropine relieves the pain associated with the inflammatory process by relaxing the ciliary muscle spasm and helps prevent posterior synechiae by dilating the pupil. 

Ciliary muscle spasm due to contraction of the ciliary sphincter muscle, with accommodative. spasm, myopia, and reduced visual acuity. 

The adverse effects of pilocarpine are caused by the induction of miosis. The contraction of the ciliary muscle causes the lens to displace forward, which can lead to accommodation spasm, myopia, and brow ache. Pupillary constriction can also affect night vision. Pilocarpine should be avoided in patients with severe myopia, as it increases the risk of developing retinal detachment. Systemic effects may occur at higher concentrations and include, nausea, vomiting, diarrhea, and bradycardia. 

Effect on the eye. Leopold and Comroe4 recorded the actions of D.F.P. on the normal eye, expanding the earlier British work (pp. 2, 43). They confirmed the prolonged myosis lasting up to 3 weeks with a spasm of the ciliary muscle for 3-7 days. There is usually a decrease in the intra-ocular tension, although occasionally there may be a slight rise before a fall in pressure. The action outlasts that of common myotics, and a 0-1 per... 

Actions Applied topically to the cornea, pilocarpine produces a rapid miosis and contraction of the ciliary muscle. The eye undergoes a spasm of accommodation, and vision is fixed at some particular distance, making it impossible to focus (Figure 4.7). [Note the opposing effects of atropine, a muscarinic blocker, on the eye (see p. 45).] Pilocarpine is one of the most potent stimulators of secretions such as sweat, tears, and saliva, but it is not used for this purpose. 

Because of its activity at muscarinic receptor sites on the iris sphincter and ciliary muscles, pilocarpine causes pupillary constriction and varying degrees of accommodative spasm, depending on the patient s age. Longterm therapy with pilocarpine or other miotics alters iris muscle activity and may cause permanent miosis resulting from loss of iris radial muscle tone and from fibrosis of the sphincter muscle. 

Eye miosis and spasm of the ciliary muscle occur so that the eye is accommodated for near vision. Intraocular pressure falls due, perhaps, to dilation of vessels at the point where intraocular fluids pass into the blood. 

Pain in and around the eye is another symptom that is commonly reported following vapor exposure. For example, in the Tokyo subway terrorist incident, 45% to 55% of the victims reported eye pain (Kato Hamanaka, 1996 Ohbu et al., 1997 Okumura et al., 1996). The pain is due to ciliary spasm and can become significantly worse when the victim looks at a bright light (Sidell, 1997). Local instillation of an anticholinergic drug (atropine, homatropine) can relieve the pain, but because this, in turn, causes blurred vision due to a paralysis of the ciliary muscles (Moylan-Jones Thomas, 1973 Nozaki Aikawa, 1995), this treatment has been recommended only in cases of severe pain. 

Spasm of the ciliary muscle may impair accommodation and is associated with severe headache. Long-lasting miosis, associated with eye pain, was a notable clinical sign in the Tokyo Subway (underground railway) terrorist attack with sarin and the same was true of the sarin attack at Matsumoto (Nohara and Segawa, 1996). 

Miosis, spasm of ciliary muscle of the eye, bronchoconstriction, bradycardia, abdominal cramps, diarrhoea, involuntary urination... 

Systemic effects which may occur from cholinergic eye-drops include nausea, diarrhoea, abdominal pain, muscle spasm and weakness, sweating, lacrimation, salivation, hypotension, bradycardia, bronchial constriction, respiratory failure and nightmares. Ocular effects, contributing to the decrease in lOP, are pupillary constriction, ciliary muscle contraction, dilatation of the conjunctival and iris blood vessels and increased aqeous outflow. The visual complications include accommodative spasm, myopia and reduced visual acuity changes in vision sensitivity, dark adaptation and visual fields may occur (20 ). 

Exposure of the eyes to nerve agent vapour exposure usually causes miosis and ocular pain due to spasm of the sphincter muscles of the iris and ciliary body, and dimmed or blurred vision. The eye discomfort is characterised as a sharp or aching ocular pain and can be associated with a mild-to-severe headache. Sometimes, the pain is accompanied by nausea and vomiting. The duration of miosis is variable, ranging from several days to as long as 9 weeks. 

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