What is the mechanism of developing Exophthalmos/ Proptosis?

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We know that Exophthalmos is a feature of hyperthyroidism, What mechanism causes these eye features e.g., diplopia, proptosis, lidlag. Thanks
In endocrine-related exophthalmos, protrusion of the eyeballs is the result of an underlying hormonal disorder and double vision results from swelling and scarring in the eye muscles, causing abnormal alignment and motion of the eyes.

Ptosis and lid lag
Ptosis: Drooping of the eyelid. Can be unilateral or bilateral, complete and incomplete, acquired and congenital. Common causes include:

Horner's syndrome Sympathetic paralysis causing partial, unilateral ptosis occurring with ipsilateral pupillary constriction and lack of sweating.
3rd nerve lesion Usually complete, unilateral ptosis with ophthalmoplegia (eye pointing outward) and pupil dilated and non-reactive.
Myopathy E.g. myasthenia gravis. Can be unilateral but usually bilateral ptosis.
Plexiform neuroma This is associated with neurofibromatosis type I
Levator dehiscence (aponeurotic ptosis) Unilateral due to damage to the superior rectus-levator muscle that may be iatrogenic during suturing. Senile form is bilateral.
Congenital Often presents at birth but may appear in first 12 months. Can be associated with poor visual acuity or strabismus. 3 Can be idiopathic or:

Neuropathic - Horner's syndrome or 3rd nerve lesion (as above) or Marcus Gunn jaw-winking syndrome (eye winks when moving jaw)
Damage at birth
Perio-orbital tumours
Neuroma or neurofibroma
Scarring.


Lid lag
Delay in moving eye lid as eye moves downwards. Causes include hyperthyroidism (due to raised sympathetic tone), anxiety4 and childhood Graves' disease. 5

References Used

MRCOphth Success in MRCOphth part 2 - Ptosis information
Oxford Handbook of General Practice, Eds Simon C et al. OUP 2003.
Suh.D.W on eMedicine
MedDean at Loyola University Chicago website
Chan W, Wong GW, Fan DS, et al; Ophthalmopathy in childhood Graves' disease.;Br J Ophthalmol 2002 Jul;86(7):740-2.[abstract]  (+ info)

Why does excess thyroid hormone cause exophthalmos?

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Graves Disease is one of the most common causes of Hyperthyroidism (excess thyroid hormone)

"In the case of Graves' Disease, the displacement of the eye is due to abnormal connective tissue deposition in the orbit and extraocular muscles which can be visualized by CT or MRI.[1]"  (+ info)

what are the named eye signs in thyrotoxic exophthalmos?they are said to be 40 of them,what are they?

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Prominence of the eyes is the most important sign. A wild or staring expression is often observed. Lag of the lids behind the globes on downward rotation and lag of the globes behind the lids in upward rotation, infrequent blinking, failure to wrinkle the forehead on looking upward, and decreased ability to converge are also cardinal manifestations. Swelling of the lids is a characteristic and frequent eye sign. The bulbar conjunctiva may be edematous (chemosis). The insertions of the medial and lateral rectus muscles are often enlarged, inflamed, and quite obvious . The lacrimal gland may protrude below the orbital bone margin.
a list would look something like;;;;
Ophthalmic phenomena reflecting thyrotoxicosis per se and apparently resulting from sympathetic overactivity:
Lid reaction
Wide palpebral aperture (Dalrymple's sign)
Lid lag (von Graefe's sign)
Staring or frightened expression
Infrequent blinking (Stellwag's sign)
Absence of forehead wrinkling on upward gaze (Joffroy's sign)
Ophthalmic phenomena unique for Graves' disease and caused by specific pathologic changes in the orbit and its contents:
Inability to keep the eyeballs converged (Mobius' sign)
Limitation of movement of the eyeballs, especially upward
Diplopia
Blurred vision due to inadequate convergence and accommodation
Swelling of orbital contents and puffiness of the lids
Chemosis, corneal injection, or ulceration
Irritation of the eye or pain in the globe
Exophthalmos (also produces mechanically a wide palpebral fissure)
Visible and palpable enlargement of the lacrimal glands
Visible swelling of lateral rectus muscles as they insert into the globe, and injection of the overlying vessels
Decreased visual acuity due to papilledema, retinal edema,
retinal hemorrhages, or optic nerve damage

wanna know more?  (+ info)

does any1 know what is exophthalmos gravidarum?

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its 4 a&p
Exopthamlmos is the "eyes popping out" appearance that occurs with hyperthyroidism, most commonly with Grave's disease.

The gravidarum tells you that it is related to pregancy.  (+ info)

In which of the following illnesses does the thyroid gland produce excessive amounts of thyroxine causing an?

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Increased metabolic rate and exophthalmos in the patient?

A. Acromegaly
B. Cushing's Syndrome
C. Addison's Disease
D. Graves' Disease
  (+ info)

can long term eyeglasses wearing cause bulging eyes?

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my nurse friend told me that wearing the same pair of glasses for a long time can cause exophthalmos. I said she's crazy. Is she?
I don't know if she's crazy, but she is wrong. :)  (+ info)

help me with this diagnosis for college!?

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ok.
here is the symptoms/description of patient
26 year old female, acne, irritability, mood swings, self abusing talk (such as I'm a loser), depression, societal withdrawal, anxiety, nervousness, hands shake when sitting still, exophthalmos, insomina, rashes on hands, extreme appetite, numb feelings in legs, patient also picks face occasionally, stares out into space (extremely disconnected with real world), has troubled relationships with friends, smokes, drinks excessively.

the question is.. is it potentially graves disease, or is it drug addiction?
Hmm..sounds like drug addiction to me  (+ info)

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