Ophthalmoparesis refers to weakness (-paresis) or paralysis (-plegia) of one or more
extraocular muscles
The extraocular muscles (extrinsic ocular muscles), are the seven extrinsic muscles of the human eye. Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye and the oth ...
which are responsible for
eye movements. It is a physical finding in certain
neurologic, ophthalmologic, and endocrine disease.
Internal ophthalmoplegia means involvement limited to the pupillary sphincter and ciliary muscle. External ophthalmoplegia refers to involvement of only the extraocular muscles. Complete ophthalmoplegia indicates involvement of both.
Causes
Ophthalmoparesis can result from disorders of various parts of the eye and nervous system:
* Infection around the eye. Ophthalmoplegia is an important finding in
orbital cellulitis.
* The
orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...
of the eye, including mechanical restrictions of eye movement, as in
Graves' disease
Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an enlarged thyro ...
.
* The
muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of mus ...
, as in
progressive external ophthalmoplegia or
Kearns–Sayre syndrome.
* The
neuromuscular junction
A neuromuscular junction (or myoneural junction) is a chemical synapse between a motor neuron and a muscle fiber.
It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction.
Muscles require innervation ...
, as in
myasthenia gravis
Myasthenia gravis (MG) is a long-term neuromuscular junction disease that leads to varying degrees of skeletal muscle weakness. The most commonly affected muscles are those of the eyes, face, and swallowing. It can result in double vision, ...
.
* The relevant
cranial nerve
Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and ...
s (specifically the
oculomotor,
trochlear, and
abducens), as in
cavernous sinus syndrome or
raised intracranial pressure.
* The brainstem
nuclei of these nerves, as in certain patterns of brainstem stroke such as
Foville's syndrome.
* White matter tracts connecting these nuclei, as in
internuclear ophthalmoplegia, an occasional finding in
multiple sclerosis
Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This ...
.
*
Dorsal midbrain
The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal ( alertness), and temperature regulation. The name comes from the Greek ''mesos'', ...
structures, as in
Parinaud's syndrome.
* Certain parts of the
cerebral cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting o ...
(including the
frontal eye fields), as in
stroke
A stroke is a disease, medical condition in which poor cerebral circulation, blood flow to the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemorr ...
.
* Toxic
envenomation by
mambas,
taipan
Taipans are snakes of the genus ''Oxyuranus'' in the elapid family. They are large, fast-moving, highly venomous, and endemic to Australia and New Guinea. Three species are recognised, one of which, the coastal taipan, has two subspecies. Taipa ...
s, and
kraits.
Thiamine
Thiamine, also known as thiamin and vitamin B1, is a vitamin, an essential micronutrient, that cannot be made in the body. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosphorylated forms of thi ...
deficiency can cause ophthalmoparesis in susceptible persons; this is part of the syndrome called
Wernicke encephalopathy. The causal pathway by which this occurs is unknown. Intoxication with certain substances, such as
phenytoin
Phenytoin (PHT), sold under the brand name Dilantin among others, is an anti-seizure medication. It is useful for the prevention of tonic-clonic seizures (also known as grand mal seizures) and focal seizures, but not absence seizures. The in ...
, can also cause ophthalmoparesis.
Diagnosis
Classification
Ophthalmoparesis can involve any or all of the extraocular muscles, which include the
superior recti,
inferior recti,
medial recti,
lateral recti,
inferior oblique
The inferior oblique muscle or obliquus oculi inferior is a thin, narrow muscle placed near the anterior margin of the floor of the orbit. The inferior oblique is one of the extraocular muscles, and is attached to the maxillary bone (origin) and ...
and
superior oblique muscles.
It can also be classified by the directions of affected movements, e.g. "vertical ophthalmoparesis".
Treatment
Treatment and prognosis depend on the underlying condition. For example, in thiamine deficiency, treatment would be the immediate administration of vitamin B1.
See also
*
Paresis
References
External links
{{Authority control
Disorders of ocular muscles, binocular movement, accommodation and refraction