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Guilherme Mazui

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What is the Difference Between Internal and External Ophthalmoplegia?

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The main difference between internal and external ophthalmoplegia lies in the muscles they affect. Ophthalmoplegia is a condition characterized by paralysis or weakness in the eye muscles. Here are the key differences between the two types:

  • Internal Ophthalmoplegia: This type of ophthalmoplegia affects the intrinsic (internal) eye muscles that control pupil size and accommodation (focusing). These muscles include the ciliary muscle, which controls the shape of the lens to allow the eye to focus, and the dilator pupillae and sphincter pupillae, which control the size of the pupil to allow in more or less light, respectively.
  • External Ophthalmoplegia: This type of ophthalmoplegia affects the extraocular (extrinsic) eye muscles that move the eyes. These muscles include the superior and inferior recti, lateral and medial recti, and upper and lower obliques, which work together to allow the eye to move up, down, side to side, and to roll in a circle.

Both internal and external ophthalmoplegia are eye conditions with a neurological basis and are considered ocular disease conditions. The severity, duration, and recovery of these conditions may vary depending on the underlying cause and the specific muscles affected.

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  • What is the Difference Between Internal and External Ophthalmoplegia?
  • Comparative Table: Internal vs External Ophthalmoplegia

    • Comparative Table: Internal vs External Ophthalmoplegia

    Here is a table comparing internal and external ophthalmoplegia:

    Feature Internal Ophthalmoplegia External Ophthalmoplegia
    Definition Paralysis of the intrinsic eye muscles, specifically the pupillary sphincter and ciliary muscle Paralysis of the extrinsic eye muscles that move the eyes
    Causes Damage to the medial longitudinal fasciculus, multiple sclerosis Disorders of various parts of the eye and nervous system, infection around the eye, orbital cellulitis, Graves' disease, progressive external ophthalmoplegia, Kearns–Sayre syndrome, myasthenia gravis
    Symptoms Pupillomotor abnormalities, decreased accommodation Ptosis (drooping of the upper eyelid), paresis (weakness) or paralysis of the third, fourth, and sixth cranial nerves
    Recovery May recover faster than external ophthalmoplegia Recovery rate varies depending on the severity and duration of the condition
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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of SĂŁo Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.