optic nerve Flashcards
Which 4 of the following nerves are strictly MOTOR in function? (Select 4)
Cranial nerve I Cranial nerve IV Cranial nerve VI Cranial nerve II Cranial nerve XI Cranial nerve III
Cranial nerve IV
Cranial nerve VI
Cranial nerve XI
Cranial nerve III
CN1,2,8 -> sensory
CN5,7,9, 10 –> both
Which 2 of the following pupil anomalies would cause anisocoria that is more prevalent in bright lighting? (Select 2)
Oculomotor palsy Horner's syndrome Acute Adie's tonic pupil Physiologic anisocoria Marcus Gunn pupil Argyll Robertson pupil
Oculomotor palsy
Acute Adie’s tonic pupil
More prevlalent in bright light = CAN NOT constrict 1- ADIES 2-CN3 palsy 3- pharmglogical agent 4- iris sphincter damage
A 9-year old patient presents with a unilateral ptosis of the left eyelid that improves in position when he widely opens his jaw. This condition, known as Marcus-Gunn jaw winking, is the result of aberrant connections between which 2 of the following cranial nerves? (Select 2)
Cranial nerve III Cranial nerve VI Cranial nerve II Cranial nerve V Cranial nerve VII Cranial nerve IV
CN3,CN5
Marcus-Gunn jaw winking is a phenomenon that is thought to occur as a result of an abnormal connection between cranial nerve V and cranial nerve III. Branches from the motor root of the trigeminal nerve that are meant for the ipsilateral pterygoid muscle aberrantly connect with the ipsilateral levator muscle instead. This allows for an elevation effect of the upper eyelid when jaw movements are initiated. This type of aberrant innervation may occur in up to 5% of patients presenting with a congenital ptosis; it tends to lessen in severity with age. This condition should not be confused with aberrant regeneration of cranial nerve VII; it is an isolated neurologic finding and does not require further work-up. Furthermore, Marcus-Gunn jaw winking is typically monitored indefinitely unless there is cosmetic concern and/or surgical intervention is desired.
A patient with bilateral tilted discs whose crescents are inferior and nasally displaced will typically display a defect located along which portion of the visual field test?
Superior temporal
Inferior nasal
Superior nasal
Inferior temporal
Superior temporal
Which area of the retina naturally corresponds with a sensitivity of 0 decibels on visual field testing?
The papillomacular bundle The macula The inferior arcade The optic nerve head The superior arcade
The optic nerve head
The optic nerve head, also known as the blind spot, will demonstrate a sensitivity of 0 decibels, because this area of the eye does not contain any visual receptors, and therefore does not possess any viable vision. The area of the retina with the highest decibel level (hence the highest sensitivity) as seen with visual field testing is the fovea. The sensitivity to stimuli decreases with increasing distance from the fovea.
Which of the following vessels provides the majority of the blood supply to the optic nerve head?
Long posterior ciliary arteries
Central retinal artery
Anterior ciliary arteries
Short posterior ciliary arteries
Short posterior ciliary arteries
Which of the following pupillary fibers is damaged in patients presenting with an Adie’s tonic pupil?
Pre-ganglionic parasympathetic
Post-ganglionic parasympathetic
Pre-ganglionic sympathetic
Post-ganglionic sympathetic
Post-ganglionic parasympathetic
Which 2 of the following signs and symptoms can aid in differentiating between a microvascular and compressive third cranial nerve palsy? (Select 2)
The presence of pain is more common in aneurysmal third nerve palsies
Aberrant regeneration typically result from microvascular third nerve palsies
Microvascular third nerve palsies do not typically involve the pupil
Third nerve palsies due to compressive lesions will always have an affect on pupil size
Third nerve palsies associated with microvascular disease commonly spontaneously resolve within 3 months
Microvascular third nerve palsies do not typically involve the pupil
Third nerve palsies associated with microvascular disease commonly spontaneously resolve within 3 months
There are several signs and symptoms that clinicians utilize in order to aid in differentiating between microvascular and compressive third nerve palsies. Some of these are summarized below:
- Third nerve palsies associated with microvascular disease commonly spare the pupil due to the superficial location of pupillary fibers as they travel in the nerve
- Third nerve palsies associated with compressive lesions commonly involve the pupil due to compression of the superficial pupil fibers
- It is important to note that this is only a general principle; there are several cases in which compressive lesions do not affect the pupil initially but may eventually if the lesion continues to grow (also, some diabetic palsies have been shown to cause pupil dilation)
- Third nerve palsies due to microvascular lesions will typically resolve within a period of three months (if a suspected microvascular lesion does not resolve within this time, imaging must be completed)
- Aberrant regeneration will only occur following acute traumatic or compressive third nerve palsies (but never after a microvascular palsy) due to the fact that the endoneural nerve sheaths remain intact in vascular pathology
- The presence of pain is common in both diabetic and aneurysmal third nerve palsies; therefore, it cannot be used to differentiate the two
A healthy retinal nerve fiber layer is thickest at which portion of the optic nerve head?
Superiorly
Temporally
Inferiorly
Nasally
inferior
ISN’T rule
thickest is Inferior , superior –> first get affected in glaucoma
You are performing a slit-lamp examination on your 37 year-old male patient. He is having difficulty keeping his eyes open due to the bright light. This is an example of which of the following reflexes?
Menace Pupil Facial Corneal Dazzle
answer is Dazzle –>bilateral narrowing of the palpebral fissures
Menace –>bilateral reflexive closure of the eyelids when OBJECT get closer
The trigeminal nerve has three main divisions. Which of the following corresponds to division 1 of the trigeminal nerve (V1)?
Ophthalmic division Infratrochlear Posterior ethmoid Long ciliary Supraorbital
ophthalmic
CN5 = trigeminal
v1–> ophthalmic(NFL)
Nasociliary ( LINES ),long ciliary ,inferior trochlear ,nasocailiary,ethmoid,short ciliary
Frontal–> supraorbital and the supratrochlear
v2-> maxillary
v3–> mandibular
Which of the following medications has been identified as a risk factor for the development of non-arteritic anterior ischemic optic neuropathy (NAION)?
Simvastatin Hydrochlorothiazide Sildenafil Celecoxib Omeprazole Atenolol
Sildenafil
VIAgra
Viagra= slidenafil
imitrex
amiodarone
Which of the following conditions has been associated with an intact pupillary light response and absent near response?
Aberrant regeneration of the third nerve Myotonic dystrophy There is no clinical condition in which this exists Diabetes Adie's tonic pupil Neurosyphilis
There is no clinical condition in which this exists
but
dissociation of light and near responses in which the light reflex is either absent or sluggish and the near response is normal.
What is the correct order of the optic nerve meninges progressing from most external to most internal?
Dura mater, arachnoid, pia mater Arachnoid, dura mater, pia mater Dura mater, pia mater, arachnoid Pia mater, arachnoid, dura mater Arachnoid, pia mater, dura mater
Dura mater, arachnoid, pia mater
Which of the following optic nerve conditions results from an increase in intracranial pressure?
Papilledema
Ischemic optic neuropathy
Papillitis
Optic neuritis
Papilledema
Papilledema is defined as passive swelling of the optic disc caused by increased intracranial pressure, usually as a result of intracranial tumors or malignant hypertension. The condition is almost always bilateral, and vision is usually normal unless there is associated edema or exudates in the macular area.
Optic neuritis is inflammation of the optic nerve that can occur at any location as it courses from the eye. It is typically caused by swelling and destruction of the myelin sheath that surrounds the nerve.
Papillitis is a specific type of optic neuritis in which there is an inflammation of the optic nerve head. This condition is almost always unilateral, and because the optic nerve is inflamed, it is commonly associated with vision loss.
Ischemic optic neuropathy is caused by obstruction of blood flow to the optic nerve, resulting in the loss of structure or function of a portion of the nerve. It is classified as either arteritic or non-arteritic, according to the location of the nerve that is affected. Patients with this condition will often present with acute loss of visual acuity and an altitudinal visual field defect.
