Ocular muscles

The predominant feature of Thomsen s disease is severe myotonia, worse in the cold and early morning than later in the day or in the warmth, unassociated with significant muscle weakness, degeneration, or other severe pathology. Myotonia is particularly common in ocular muscles, and muscles of the arms and legs. Onset is typically during childhood. 

Thyroid-associated ophthalmopathy (TAO) is present in 90% of patients with the classical triad of Graves disease (goiter, ophthalmopathy, dermopathy) but these features may follow independent courses and successful control of the hyperthyroidism improves TAO in less than 5% cases. Immunosuppression has been used since theories of the etiology of TAO include the presence of circulating antibodies to both thyroid and ocular muscle fibers, and of thyroglobulin-antithy-roglobulin complexes with high affinity for extraocular muscles. 

D-penicillamine a well-recognized complication of the use of D-penicillamine is a myasthenic syndrome. Most reported cases of myasthenic syndrome are women and the ocular muscles appear to be particularly commonly affected at early stages of the abnormality. The onset of the myasthenic syndrome can range between a few months and many years, and is not always reversible. There is a clear immunological basis to this problem, because it is associated with raised anti-acetylcholine receptor antibodies circulating in the serum. Antibody levels fall when the drug is withdrawn, and this, in turn, is associated with clinical improvement. How the... 

As the ocular muscle enters the orbit, its appearance changes dramatically. Most of the muscle cytoplasm is lost, contractile proteins largely disappear, and mitochondrial abundance increases dramatically, to assume up to about two-thirds of cell volume. Another striking feature of heater organ cells is the development of an elaborate membrane wrapping around the mitochondria (figure 7.32). This extensively developed membrane system is derived from the sarcoplasmic reticular membranes. The high densities of ion pumps in the... 

About 30% of adult Tangier patients present with peripheral neuropathy, the onset of which usually takes place after 10 years of age. These neuropathic symptoms may be subtle or overt, transient or permanent, and include weakness, increased sweating, diplopia (double vision), ptosis (abnormally drooping eyelids), ocular muscle palsies, and diminished or absent deep-tendon reflexes. There are two prototypes of neuropathy found in Tangier dis-... 

As shown, tetanizing stimulation of the sciatic nerve produced contraction of the gastroneumius muscle and reflex increase in BP and respiration. Occlusion of the carotid artery causes increased BP and HR. Pressure on the ocular muscles decreases BP and respiration. Due to their transitory nature, many other reflexes can be used. 

SAFETY PROFILE Human poison by unspecified route. Human systemic effects by ingestion nerve or sheath structural changes, extra-ocular muscle changes, sweating, and other effects. Flammable in the form of dust when exposed to heat or flame. Violent reaction with F2. When heated to decomposition it emits toxic fumes of Tl. Used as a rodenticide and fungicide, and in lenses and prisms, in high-density liquids, See also THALLIUM COMPOUNDS and POWDERED METALS. 

In addition to these medical and surgical therapies, optical management of ptosis using dark lenses or a ptosis crutch may also be indicated. For smaller constant ocular muscle misalignments, Fresnel press-on prisms may be used. An opaque (occluder) lens may be needed for larger fluctuating deviations. 

Leebeck MJ. Effect of drugs on ocular muscles. Int Ophthalmol Clin 1971 11 35-62. 

Ocular malformations, including aplasia of the macula, choroidal colobomata, microphthalmos, and extraocular muscle paresis have been attributed to thalidomide taken in early pregnancy (135). Ocular defects have been reported in four of 21 thalidomide children examined in Canada there was strabismus in two cases, congenital blepharoptosis in one, and ocular muscle palsies associated with other central nervous system damage in one (136). 

Ocular External ocular muscles, some involvement of face, neck, arms. 

Ophthalmoplegia Paralysis of one or more of the ocular muscles due to disorders of the eye muscles, neuromuscular junction, supporting soft tissue, tendons, or innervation to the muscles. [NIH]... 

Abramowicz M, ed. Botulinum toxin for ocular muscle disorders. Med Lett. 1990 32(830) 100 101. 

Salthouse TN, Matlaga BF and Wykoff MH. Comparative tissue response to six suture materials in rabbit cornea, sclera and ocular muscle. Am. J. Ophthalmol. 84 224-233,1977. 

Ocular muscles that move the eye are attached lo the sclera. 

A number of CWAs exert their effects by modulating neuronal control over ocular function (Table 38.2). Autonomic neurons provide input to the intrinsic ocular muscles (the sphincter pupillae, the dilator pupillae, and the ciliary muscle) and e lacrimal glands. Neuronal afferents in the eye include sensory neurons from the conjunctiva and cornea, reflexive contributions to the iris, ciliary muscle, and eyelids, and the densely innervated retina. Finally, the extraocular muscles and eyelids are controlled by cholinergic motor neuron inputs. 

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