what area of vision is affected with methanol.
what area is affected by tobacco toxicity
- why with tobacco?
central vision, macular
tobacco laced with cyanide...
What mode of inheritance is Lebers optic neuropathy?
describe Lebers optic neuropathy
acute phase - optic nerve is hyperemic and swollen with telangiectatic capillaries. it does not leak on FA. later its just atrophy. affects macular vision!
degeneration of retinalganglion cells (RGCs) and their axons that leads to an acute or subacute loss of central vision; this affects predominantly young adult males
enlarged or telangectatic and tortuous peripapillary vessels (microangiopathy)
A pupillary defect may be visible in the acute stage as well. Examination reveals decreased visual acuity, loss of color vision and a cecocentral scotoma on visual field examination.
needs EKG - may have cardiac arrythmia!
optic nerve lesion/cut
produces blindness in one eye with contralateral superotemporal defect
what is the pathognomonic sign of myasthenia gravis?
fatigable ophthalmoplegia. in any gaze.
it can be confined to the eye
after two years, if only eye, <20% will go systemic
what is in the differential for slowly progressing ptosis
chronic progressive external ophthalmoplegia
CPEO - what is it
A mild form of what syndrome?
what is the inheritance?
Kearns-Sayre Syndrome - with pigmentary retinpathy and heart block
this is a primary myopathy
"Ragged Red Fibers"
long history of gradually worsening ptosis
cannot move eye muscles, head turns to see
head tilted up due to ptosis
pupils are spared!
Oculocraniosomatic neuromuscular disease with ragged red fibers is amitochondrial myopathy
how is CPEO different from progressive supranuclear palsy?
PSP typically spares the horizontal gaze and affects only vertical gaze
What gaze deviation is caused by a lesion in the right sixth nucleus
ipsilateral (right) gaze palsy - common neurons via MLF...
what are the signs of parinauds dorsal midbrain syndrome
skew deviation, lid retraction - collier's sign, and pupillary light-near dissociation.
- possible supranuclear palsy
- upgaze paralysis
- contraction-retraction nystagmus
Kearns Sayre Syndrome
what is the retinopathy?
how about the heart finding
KSS results in a pigmentation of the retina, primarily in the posterior fundus. The appearance is described as a "salt-and-pepper" appearance. There is diffuse depigmentation of the retinal pigment epithelium with the greatest effect occurring at the macula. This is in contrast to retinitis pigmentosa where the pigmentation is peripheral. The appearance of the retina in KSS is similar to that seen in myotonic dystrophy type 1 (abbreviated DM1). Modest night-blindness can be seen in patients with KSS. Visual acuity loss is usually mild and only occurs in 40–50% of patients.
Cardiac conduction abnormalities
These most often occurs years after the development of ptosis and ophthalmoplegia. Atrioventricular(abbreviated "AV") block is the most common cardiac conduction deficit. This often progresses to a Third-degree atrioventricular block
Can you describe the Park's three step test
isolate the palsy muscle
RSR RIO LIO LSR
RIR RSO LSO LIR
Double mattox rods?
takes a point source of light and oconverts into a straight line, place lenses in front of each eye, the patient can rotate one of the rods until the lines are parallel
useful for torsional measurement
red filter/muscle light
vertical and horizontal diplopia
neutral density filters
APD, subjective light difference
salt and pepper fundus
retinitis pigmentosa can be part of the constellation of disorders seen in systemic diseases and syndromes, such as Bardet-Biedl, Bassen-Kornzweig, Kearns-Sayre, Refsum’s, Stargardt’s and Usher’s.
Salt-and-pepper fundus with diffuse pigmentary lesions can be the signature of a previous systemic infection that had ocular involvement. Examples include inactive chorioretinal scars secondary to Lyme disease, tuberculosis, syphilis, congenital rubella, toxoplasmosis and bartonellosis.
A variety of pharmacologic agents taken at a high dose and for an extended duration such as chloroquine, hydroxychloroquine and thioridazine can all lead to pigmentary retinopathies as well.
CN3 palsy and contralteral decreased sensation and tremor (red nucleus) ..cerebellar ataxia including tremor. Neuroanatomical structures affected include CNIII nucleus, Red nucleus, corticospinal tracts, brachium conjunctivum, and cerebellum. It is very similar in etiology, morphology and clinical presentation to Weber's syndrome; the main difference between the two being that Weber's is more associated with hemiplegia (i.e. paralysis), and Benedikt's with hemiparesis (i.e. weakness).
Weber's syndrome (superior alternating hemiplegia) is a form of stroke characterized by the presence of an oculomotor nerve palsy and contralateral hemiparesis or hemiplegia.
brachium conjunctivum and ipsilateral cerebellar ataxia
Tolosa–Hunt syndrome (THS) is a rare disordercharacterized by severe and unilateral headacheswith extraocular palsies, usually involving the third, fourth, fifth, and sixth cranial nerves, and pain around the sides and back of the eye, along with weakness and paralysis (ophthalmoplegia) of certain eye muscles.
inflammation of the areas behind the eyes (cavernous sinus and superior orbital fissure).
Tx is steroids
diagnosis of exclusion
aberrant consequence of nerve regeneration subsequent to Bell's palsy or other damage to the facial nerve in which efferent fibers from the superior salivary nucleus become improperly connected to nerve axons projecting to the lacrimal glands, causing one to shed tears (lacrimate) during salivation while smelling foods or eating.
superior oblique myokymia
episodic twitching of the superior oblique.
pt experiences a slight rotary sensation lasting from seconds to minutes.
carbamazepine/propranol effective TX
More recently, magnetic resonance imaging experiments have shown that neurovascular compression at the root exit zone of the trochlear nerve can result in superior oblique myokymia
which nerve is most commonly injured following closed head injury?
trochlear CN 4
longest intracranial course.
followed by CN 6
*anything that raises intracranial pressure can result in CN6 palsy*
T/F CN3 palsy caused by DM is painless
False, it may be painful or painless.
Aneurysm as a cause is usually painful.
DM palsy tends to resolve and spares the pupil (<20%)
characteristic findings for stroke
parietal lobe - ipsilateral pusuit affected. right side lesion - optokinetic nystagmus with drum rotating to the left...
temporal lobe - formed visual hallucinations
occipital lobe - unformed visual hallucinations
if you see ptosis with miosis/anhydrosis?
what about ptosis with a dilated pupil?
what about segmental contraction of the pupil
Horners syndrome - complete lack of sympathetic tone. 10% cocaine wont help you, cocaine is a norepi reuptake inhibitor, but no norepi at the jxn
CN3 palsy - with levator, may have other deviation on EOM.
Adie's tonic pupil - dilated pupil that doesnt respond in light - due to damage to the parasympathetic innervation from trauma/infection(viral/bac) etc.
If the difference in size is greater in the dark, the smaller pupil is abnormal. causes -Horner syndrome and physiologic anisocoria. differentiate -the small pupil in Horner syndrome does not dilate after instillation of an ocular dilating drop (eg, 10% cocaine).
If the difference in pupillary sizes is greater in light, the larger pupil is abnormal. If extraocular movements are impaired, particularly with ptosis, 3rd cranial nerve palsy is likely. If extraocular movements are intact - further differentiate among causes by instilling a drop of a pupillary constrictor (eg, 0.1% pilocarpine). If the large pupil constricts, the cause is probably Adie tonic pupil; if the large pupil does not constrict, the cause is probably drugs or structural (eg, traumatic, surgical) damage to the iris.
Trigeminal nerve breakdown
Trigeminal Nerve breakdown
Name the major glands in the eyelid, their fxn, location, and type of gland (apocrine/holocrine etc)
Glands of Krause
Exocrine and aqueous secreting accessory lacrimal glands located in the lamina propria of the conjunctival fornices (superior and lateral>inferior). Smaller and more abundant than wolfring
Glands of Wolfring
Exocrine and aqueous secreting accessory lacrimal glands located above the superior border of the upper lid tarsus.
Glands of Moll
Specialized apocrine (plasma membrane goes with secretion –damaging) sweat glands located at the base of the lashes anterior to the Meibomian glands.
Glands of Zeis
Modified sebaceous holocrine (cells die in order to secrete!) glands located at the base of
Glands of Krause and Wolfring possess a histologic structure similar to the lacrimal gland.
Glands of Moll are tubular, large apocrine gland.
Glands of Zeis are unilobular sebaceous gland units associated with follicles.