Chapters 7-9 Flashcards
what % of fibres in the anterior visual pathway serve central vision
90%
what makes up the anterior visual pathway
optic nerve
chiasm
tracts
what is a finding in many diseases of the optic nerve and anterior pathway
will cause red hues to become desaturated
what is an acceptable difference in pupil size?
less than 1mm is normal variation in 20% of the population
what is anisocoria
a difference in pupil size
what does a difference in pupil size (anisocoria) in DIM light indicate?
dilation SNS dysfunction–> HORNERS
what does a difference in pupil size (anisocoria) in BRIGHT light indicate?
abnormal constriction, PNS dysfunction–> 3rd NERVE PALSY, ADIE TONIC PUPIL
what does an RAPD almost always indicate
a leson in the optic nerve on the affected side or widespread/central retinal disorder (subtle)
do cataracts/vitreous hemorrhage affect pupillary reaction
no
does RAPD ever cause anisocoria
no, never
can RAPD ever be bilateral
no
what causes an RAPD
one optic nerve is less sensitive to light than the other
thus, the brain thinks the light to the normal eye is brighter than the light to the affected eye
when light is switched from the normal eye to the affected eye, the brain senses relatively less light in the affected eye and the affected pupil will DILATE
what is a mydriatic pupil
dilated pupil
with does a mydriatic pupil indicate
LOSS of PNS input to the iris sphincter
what can cause loss of PNS input to the iris sphincter (and thus cause a mydriatic pupil)
- oculomotor nerve paresis –> check with MRI
- benign ciliary ganglionopathy (adie tonic pupil)
- trauma to the orbital parasympathetic system (traumatic mydriasis)–> check with CT
- dorsal midbrain syndrome–> MRI
- prior iris damage/surgery
- pharmacologic
what does CN III do
controls pupillary sphincter muscles and some of the muscles of ocular movements
what happens when CN III is compromised
third nerve palsy
causes eyelid proptosis, pupil dilated and poorly reactive, eye loses ability to elevate, depress or move nasally
eye is turned OUTWARD and SLIGHTLY DOWNWARD
what direction does the eye point in a third nerve palsy
outward and slightly downward
how should you manage a new onset third nerve palsy
must undergo immediate, urgent MRI, CV imaging to rule out neural compression
what is the most common cause of third nerve palsy
circle of willis aneurysm
what usually causes a dilated fixed pupil in an otherwise healthy individual with normal ocular motility
usually benign and may be due to migraine, adie tonic pupil, dilating agents or secondary to previous ocular trauma
what is perinaud syndrome
dorsal midbrain syndrome
damage/compression to the upper brainstem
what causes dorsal midbrain syndrome/perinaud syndrome
can be caused by:
hydrocephalus
compressive lesion of the midbrain
MS
stroke
midbrain hemorrhage
what are the symptoms of dorsal midbrain syndrome/perinaud syndrome
loss of UPGAZE
convergence-retraction nystagmus
light-near dissociation of the pupils
eyelid retraction (collier sign)
what is collier sign
eyelid retraction
sign of dorsal midbrain syndrome
how should you manage suspected dorsal midbrain syndrome
urgen MRI
what is adie tonic pupil
benign, idiopathic, (usually) dilated pupil
what % of adie tonic pupil are unilateral
80%
what population is usually associated with adie tonic pupil
young women
how does adie tonic pupil present
tonic pupil is usually larger than the uninvolved pupil
reaction to light is diminished to absent
reaction to accomodation remains intact
what is a “small pupil”
a small pupil with normal reactivity with no ocular abnormalities
is of no neurological significance–> especially if difference is less than 1mm
must consider Horners syndrome and tertiary syphillis
what are the symptoms of Horner’s syndrome
small pupil + ptosis
due to loss of SNS tone from Horner’s
what causes Horner’s
dysfunction of the extensive SNS pathways
can be caused by carotid dissection, cavernous carotid aneurysm, apical lung tumour
how do you confirm Horner’s
pharmacologic testing–> eye drops (APRACLONIDINE) will cause significant elevation of the eyelid and dilation of the pupil in an eye with Horner’s
what eye drop is used to test for Horner’s
apraclonidine–> will cause elevation of eyelid and dilation of pupil
how should you manage a horner’s syndrome
should have MRI
majority are idiopathic
what is a argyll robertson pupil
associated with tertiary syphilis
results in small, irregular pupils that demonstrate light-near dissociation
both pupils are usually involved but can be asymmetric
why does tertiary syphilis cause argyll robertson pupils
it can affect the fibres of the midbrain and pupillary light reflex
how should you manage argyll robertson pupil
should have serological testing for syphilis and MRI of brainstem
what nerve innervates the superior oblique muscle of the eye
CN IV
how does a complete paralysis of CN IV present (complete CN IV palsy)
vertical diplopia when down-gaze and contralateral side-gaze
what is the most common cause of CN IV palsy
microvascular disease–HTN, DM
trauma also common since CN IV is very thin
common congenital anomaly that presents in adulthood
what is the caused of a BILATERAL CN IV palsy
closed head trauma
what nerve supplies the lateral rectus muscles of the eye
CN VI
how does a complete paralysis of CN VI present? (CN VI palsy)
produces loss of ABDUCTION resulting in horizontal diplopia worse when gaze is towards affected side
what is the most common cause of CN VI palsy
microvascular disease (HTN, DM, smoking, hyperlipidemia)
98% spontaneously recover within 3-4 months
can also be caused by tumour (20%) or increased ICP which can lead to compression (CN VI is the most susceptible to this)
how do you manage a CN VI palsy
98% spontaneously recover within 3-4 months so treatment is initial watchful waiting period of 4 months
if no recovery or gets other symptoms, MRI
what is the most common cause if CN VI palsy in kids
trauma
can also be post infectious or inflammation of the petrous ridge from severe otitis media
where is the lesion in an INO
in the MLF
how does an INO present
slow and weak adduction of one eye and nystagmus of the abducting eye in lateral gaze
may be unilateral or bilateral
eyes may be straight or have exotropia
what is the usual cause of an INO in adults
microvascular disease–recovers in weeks or months
what is the usual cause of an INO in a young adult
commonly due to demyelinating disease, brainstem hemorrhage or trauma
what is the usual cause of an INO in a child
pontine glioma
how should you manage an INO
MRI and myasthenia gravis should be considered
how does a patient with convergence insufficiency present
double vision when viewing near but not at a distance
patients have normal eye movement and alignment in primary gaze but have exotropia in far vision
how does a patient with divergence insufficiency present
double vision at a distance but not when reading
normal motility–measures near their eyes are straight but crossed at a distance
what is myasthenia gravis
chronic autoimmune condition that interferes with neuromuscular transmission at skeletal muscles
what are the presenting complaints in MG in 50% of patients
ptosis and double vision
for those with ocular MG, half go on to develop weakness of other skeletal muscles within 2 years
what are the symptoms of MG besides ptosis and double vision
fatigability of muscle function with sustained effort
does NOT affect the pupil
how do you diagnose MG
serology for Ach receptor antibodies, electromyography and ice pack test
define nystagmus
spontaneous, rhythmic back and forth movement of one or both eyes
what are the three most common forms of nystagmus
are BENIGN
- extremes of lateral gaze (3/4 of horizontal nystagmus)
- nystagmogenic meds (anti-epileptics, barbituates, sedatives)
- searching/pendular nystagmus (most common… congenital)
what are the three types of acquired nystagmus
cause oscillipsia and vertigo
- vestibular
- cerebellar
- brainstem dysfunction
what kinds of processes can cause an acquired nystagmus
peripheral vestibular disease
trauma
MS
brain tumours
degeneration of CNS
how do you manage an acquired nystagmus
MRI (only for acquired)
where can you usually visualize pathological nystagmuses
in the primary eye position (straight ahead)
how do you ID an optic disc elevation
via fundoscopy
seen as an indistinct disc margin, elevation of the optic disc, vascular tortuosity and absence of the central cup (disc edema)
presence of capillary hyperemia and haemorrhage on or around the disc is a sign of active disc edema
how does a congenital optic disc elevation present
normal varient
may have bright yellow, proteinacious material within the disc itself (drusen)
because of deceptive appearance, referred to as pseudopapilledema
list the characteristics of papilledema
- hyperemia of the disc
- tortuosity of the being and capillaries
- blurring and elevation of the margins of the disc
- obscuration of retinal vessels near the nerve
- haemorrhages on and surrounding the nerve head
what is papilledema
passive swelling of the optic disc secondary to increased ICP
is papilledema usually uni or bilateral
usually bilateral tho can be asymmetric
what symptoms would you expect to see with papilledema
vision may not be affected initially
blurring, flickering or second-long obstruction may occur
sx of increased ICP–headaches, nausea, vomiting, double vision
what causes increased ICP and thus papilledema
tumours
idiopathic intracranial HTN
cerebral trauma/haemorrhage
meningitis/encephalitis
dural sinus thrombosis
how do you manage papilledema
requires immediate MRI or CT scan
LP if mass and venous thrombosis ruled out
what is pseudotumour cerebri
idiopathic intracranial HTN
increased fluid pressure around the brain in absence of brain tumour, thrombosis or CSF abnormality
in which patients is pseudotumour cerebri most common
women aged 20-40
what are symptoms of pseudotumour cerebri
chronic papilledema may result in ischemia leading to vision loss
headache
transient blurred vision
pain with eye movement
pulsatile tinnitus
horizontal double vision
neck stiffness
papilledema with or without CN VI palsy
neuro exam usually NORMAL
what exposures may lead you to think of a dx of pseudotumour cerebri
steroids
excessive vitamin A
retinoic acid
tetracycline and lithium
how do you manage pseudotumour cerebri
brain MRI plus LP for opening pressure and CSF profile
what is papillitis
inflammatory edema of the disc
may be indistinguishable from papilledema but is clinically distinct
how can you try and distinguish between papillitis and papilledema
papillitis is more commonly unilateral and associated with decreased visual acuity, impaired colour, visual field defects and afferent pupillary defect
what can cause papillitis
may result from demyelination ischemia, infiltration, compression or infection
what is optic neuritis
inflammation and demyelination of the optic nerve
what should you think of when someone presents with sudden, painful loss of vision
optic neuritis
in which population is optic neuritis most common
women aged 15-45
what are the symptoms of optic neuritis
acute or subacute VISION LOSS associated with periocular pain
pain is exacerbated with eye movement and preceeds vision decline
how does anterior optic neuritis present
it is a form of papillitis
results in disc edema but swelling is usually mild
majority of optic neuritis occurs behind the eye so the optic disc appears normal
what condition is most commonly associated with optic neuritis
MS–> 50% of patients who present with optic neuritis go on to develop MS
what is the course of optic neuritis
most resolves spontaneously within weeks without treatment
may be faster with IV corticosteroids
how do you manage optic neuritis
all patients should have an MRI with and without contrast
what causes optic neuritis
may be idiopathic, post viral, systemic condition related (syphilis, sarcoidosis, collagen vascular disease)
should you refer patients with optic neuritis
yes–all should be followed up by ophtho
what should you think when someone presents with sudden, painless, unilateral loss of vision
ischemic optic neuropathy
what causes ischemic optic neuropathy
sudden microvascular infarction of optic nerve
which portion of the optic nerve is most vulnerable to ischemic optic neuropathy
anterior portion where it joins the eye
this is termed anterior ischemic optic neuropathy (AION)
this is non arteritic
how does posterior ischemic optic neuropathy present
less common
results in sudden, severe, unilateral or bilateral vision loss in the setting of SYSTEMIC HTN (or cranial surgery, zoster, vasculitis)
optic disc is swollen or normal
what is the most common form of ischemic optic neuropathy
non arteritic ischemic optic neuropathy (NAION)
which patient population is associated with non arteritic ischemic optic neuropathy
patients over 40 with atherosclerotic risk factors (HTN, diabetes, hyperlipidemia, smoking, sleep apnea, obesity)
when does non arteritic ischemic optic neuropathy happen?
DURING SLEEP
presents with unilateral vision loss first noticed WHEN WAKING
which visual fields are lost with non arteritic ischemic optic neuropathy
upper or lower half of vision affected (altitudinal)
what is always present in non arteritic ischemic optic neuropathy
RAPD
also disc edema
variable visual acuity effects
how do you manage non arteritic ischemic optic neuropathy
there are no treatments are there is little to no recovery
test with CRP and ESR to rule out temporal arteritis
how does arteritic anterior ischemic optic neuropathy present
sudden, painless, catastrophic visual loss in patients over 60
it is a cardinal feature og GIANT CELL/TEMPORAL ARTERITIS
accompanied by jaw claudication, new onset headache, visual abnormalities, elevated CRP, ESR
how do you diagnose arteritic anterior ischemic optic neuropathy/giant cell arteritis
biopsy
do all patients with visual loss and giant cell arteritis have sx
no, 1/5 do not
how do you treat arteritic anterior ischemic optic neuropathy/giant cell arteritis
IV corticosteroids ASAP to spare the other eye
what should you think of if someone has temporary painless vision loss in one eye
amaurosis fugax
what may be found on fundoscopy for someone who had amaurosis fugax
hollenhorst plaque (intra-arterial plaque) at the retinal-arterial bifurcation
what should you do to work up amaurosis fugax
evaluate for stenosis of the ipsilateral carotid, embolic sources from cardiac, temporal arteritis
ESR, CRP, carotid U/S, transesophageal echo
what should you think of if patient has transient visual loss lasting 20-40 minutes and is associated with photopsias and/or headache
migraine
define optic atrophy
morphological and physiological changes of the optic nerve as a result of damage to the ganglion cells
most easily observed as changes in the optic disc
what causes optic atrophy
result of progressive change in appearance of axons and glial tissue–may become pale and cup may enlarge
disc may appear white after extensive damage
how do you diagnose optic atrophy
should not dx unless concomitant, demonstrable optic nerve dysfunction
workup should include orbital MRI with contrast and serology
define scotoma
area of abnormal or absent vision within an otherwise intact visual field
define hemianopia
loss of half of visual field
define homonymous hemianopia
loss of either right or left half of visual field in both eyes
define bitemporal hemianopia
loss of the temporal half of the visual field in both eyes
what are some possible causes of bitemporal hemianopia
pituitary adenoma, craniopharyngioma or parasellar meningioma
what is a junctional scotoma
loss of central field in one eye and temporal visual defect in the other
where is the lesion of the presenting complaint is a scotoma or altitudinal hemianopia with accompanying pupillary defect
anterior to the chiasm
i.e optic neuritis/papillitis
optic nerve glioma
meningioma
ischemic optic neuropathy
where is the lesion if it produces a homonymous hemianopia
behind the chiasm
most commonly caused by stroke, trauma, mass lesion
what ocular abnormality is associated with a PCA stroke
a neurologically isolated homonymous hemianopia
what is charles bonnet syndrome
characterized by release hallucinations that occur in cognitively intact individuals with bilaterally decreased vision
solely see visual hallucinations that are sporadic and not associated with other neuro or cognitive defects
typically see colourful patterns, faces, animals, flowers or people
seen in 15% of people with vision worse than 20/80
treatment of charles bonnet syndrome
increased lighting and more social interaction
what ocular changes are associated with diabetes
refractive changes
RETINOPATHY
cataract formation
after 20 years, 50% of T1DM have severe subtype or proliferative diabetic retinopathy
what can cause diabetic retinopathy
may be secondary to macular edema, haemorrhage from new vessels and retinal detachment from neovascular glaucoma
majority of patients have no sx until late in disease making screening important
what are the two types of diabetic retinopathy
proliferative and non-proliferative
describe the pathogenesis of diabetic retinopathy
multifactorial
primarily caused by metabolic effects of chronic hyperglycemia –> leads to vascular changes and retinal injury/ischemia
caused by impaired autoregulation of retinal blood flow, accumulation of SORBITOL within retinal cells and accumulation of advanced glycosylation end products in the extracellular fluid
tight BP control is as important as glycemic control in preventing developments and progression of diabetes
what HbA1c is considered low risk for development of diabetic retinopathy
uncommon in patients with HbA1c below 7%
what is the first manifestation of nonproliferative diabetic retinopathy
microaneurysm formation –>
capillaries leak and eventually become occluded
what are the retinal findings in nonproliferative diabetic retinopathy
DOT AND BLOT hemorrhages
hard exudate
cotton wool spots
macular edema
what is the most common visual impairment associated wtih nonproliferative diabetic retinopathy
macular edema
what are the signs and characteristics of proliferative diabetic retinopathy
more severe progression of disease
marked by increased vascular tortuosity and haemorrhage, venous bleeding and microvascular abnormalities
because of ischemia, some new blood vessels grow over the optic disc or over the iris (causing glaucoma)
what is the leading cause of blindness in diabetics
proliferative diabetic retinopathy
how does proliferative diabetic retinopathy cause retinal detachment
neovascularization can cause bleeding into the vitreous with can cause traction and cause retinal detachment
when should T1DM patients be screened for retinopathy
screened by ophtho if have had DM for equal to or more than 5 years
when should T2DM patients be screened for retinopathy
at time of diagnosis
what condition in women can exacerbate diabetic retinopahy
pregnancy
what sign is associated with arteriolar sclerosis
COPPER WIRE ARTERIOLES–> when the light reflex becomes completely obscured you get SILVER WIRE arterioles
can get A/V crossing changes–> vein may be elevated or depressed by the arteriole which causes AV NICKING
how do you ID arteriolar sclerosis
increase in light reflex of arteriolar sclerosis depends on severity and duration of the HTN
what underlying condition causes arteriolar sclerosis
HTN
causes thickening of the walls and central light reflex increases in width
what condition is associated with AV nicking?
arteriolar sclerosis
what conditions can result due to AV Nicking
severe AV nicking can lead to branch retinal vein occlusion (BRVO)–> appears as diffuse retinal hemorrhage and cotton wool spots in the retina that is drained by the affected vein
may also have macular edema, central vision acuity decrease and may need laser therapy
what ocular changes are associated with an acute rise in BP
constriction of arterioles–>
rise greater than 120 mmHg and a systolic over 200 mmHg causes FIBRINOID NECROSIS of the vessel wall
results in exudates, cotton wool spots, flame shaped hemorrhages and sub retinal fluid
what ocular signs are associated with malignant HTN
swelling resembles papilledema and exudates assume a stellate configuration–> MACULAR STAR
how are HTN ocular changes classified
Grade 0–> no changes
Grade 1–> barely detectable arterial narrowing
Grade 2–> obvious arterial narrowing with focal irregularities
Grade 3–> Grade 2 plus retinal hemorrhage and/or exudates
Grade 4–> grade 3 plus disc swelling
what is the management of the ocular manifestations of HTN
managing the BP
what ocular changes are associated with pregnancy
lowering of IOP
decreased corneal sensitivity
transient loss of accomodation
increased incidence of central serious chorioretinopathy and uveal melanomas, and pregnancy induced HTN
how should you manage a woman who is diabetic and pregnancy from an ocular perspective
ophtho should see once a trimester
women with gestational diabetes are not at risk for retinopathy
which patients with sickle cell are more likely to have ocular involvement
sickle hemoglobin SC and sickle cell thalassemia are more likely than those with SS disease
what is the result of sickle cell on the eyes
intravascular sickling, hemolysis, hemostasis and thrombosis lead to occlusion followed by non-perfusion
retinal neovascularization can lead to vitreous haemorrhage and retinal detachment
patients with sickle cell should have baseline ophtho eval
what thyroid disease is associated with ocular manifestations
graves–> thyroid related orbitopathy
what is thyroid related orbitopathy
due to graves
due to autoantibody mediated enlargement of the extraocular muscles, orbital fat and lacrimal glands
the eyelid edema and conjunctiva vascular congestion that accompanies it do not require therapy
what is a common presentation of thyroid related orbitopathy/graves
retraction of upper and lower eyelid with upper lid lag on down gaze
diplopia is common and may require surgery –> this requires ophtho care
what is the most common cause of unilateral/bilateral protrusion of globes (exophthalmos)
thyroid related orbitopathy
results in corneal exposure and drying
how is sarcoidosis characterized histologically
focal noncaseating granulomas
in which patients is sarcoidosis most common
african american women between ages 20-40
how do you dx sarcoidosis
biopsy from conjunctiva or lacrimal gland
which disease are you testing for with a biopsy from the conjunctiva or lacrimal gland
sarcoidosis
describe the ramifications of sarcoidosis from an ocular perspective
may be asymptomatic
can cause anterior or posterior UVEITIS
anterior is inflammation of the iris and ciliary body
posterior is inflammation of the choroid
suspected patients require complete ophtho evaluation
what ocular manifestations can arise from autoimmune conditions like SLE, polyarteritis nodosa and Wegener granulomatosis
sclerokeratitis
uveitis
optic neuropathy
retinal vasculitis –> multiple cotton wool spots
what ocular manifestations are associated with juvenile rheumatoid arthritis
asymptomatic iritis in 10% of cases
iritis more common in paciarticular form than the polyarticular form
requires visit to ophtho every 3 MONTHS since the iritis is asymptomatic
the iritis can lead to cataracts, glaucoma, corneal opacification
what systemic conditions are associated with dry eye
many rheumatoid conditions–> causes keratitis sicca
most common are sjogrens, SLE, RA
treatment is artificial tears, lubricating ointment at night
what ocular manifestations may indicate rheumatoid arthritis
severe dry eyes leading to risk of corneal melting, infection, possible perforation
for severe cases, ophtho can perform punctal occlusion to retain tears
what effects can cancer treatment radiation have on the eyes
can lead to cataracts or delayed retinal vasculopathy (diabetic retinopathy type thing) and optic neuropathy
many chemo drugs also have ocular problems such as superficial keratitis
what is a common finding on autopsy of kids with leukemia
there is infiltration in 75% of kids who die of leukemia resulting in ocular adnexal mets being found on autopsy
what are the ocular manifestations of AIDS
cotton wool spots–> AIDS retinopathy
CMV retinitis
kaposi sarcoma of eyelids
less common–> shingles, herpes simplex keratitis, conjunctival microangiopathy, toxoplasma uveitis and retinitis, visual field defects or oculomotor dysfunction via CNS
why do people with AIDS get cotton wool spots
due to focal occlusions of pre-capillary retinal arterioles that results in stasis
intra retinal hemorrhages may also be found
what are the signs of CMV retinitis
characterized by SECTORAL hemorrhagic NECROSIS of the retina–> typically along a RETINAL VESSEL
what should you do when you diagnose someone with HIV
refer to ophtho
patients who can sustain a higher CD4 count are less likely to develop CMV retinitis
why is it important to treat syphilis early
late diagnosis can lead to permanent vision loss which is avoided with early treatment
what are the ocular manifestations of syphilis
acute interstitial KERATITIS and keratouveitis occurs with congenital syphilis between 5-25 years
bilateral if congenital, unilateral if acquired
what are the symptoms of ocular syphilis
intense pain
photophobia
opaque cornea
reduced vision
circular area of chorioretinal whitening may indicate CSF involvement (at RISK of neurosyphilis)
what finding on ocular exam of the patient with syphilis would suggest risk of neurosyphilis
circular area of chorioretinal whitening may indicate CSF involvement
how should you manage patients with syphilitic uveitis
get CSF tested for possible neurosyphilis
how might secondary syphilis present
iritis
retinitis
choroiditis
or papillitis
how might latent syphilis present
blurred vision
how do you treat syphilis
systemic penicillin is curative
what are the ocular manifestations of candida
fluffy, white-yellow superficial retinal infiltrate that may lead to vitreous haze and vitritis
rarely can cause inflammation of anterior chamber
how do you treat ocular candidiasis
amphotericin B with or without intravitreal amphotericin or voriconazole
what is herpes zoster ophthalmicus
varicella zoster infection involving CN V
what is Hutchinson sign
lesion on the tip of the nose from extension of herpes zoster ophthalmicus
why do we care about herpes zoster ophthalmicus
can lead to corneal infiltration
patients with anterior uveitis and keratitis (which is a serious vision threatening defect) require immediate ophtho referral
patients without skin lesions can still develop herpetic uveitis
can develop ACUTE RETINAL NECROSIS which is an OCULAR EMERGENCY requiring emergent systemic acyclovir
how do you manage acute retinal necrosis from herpes zoster ophthalmicus
OCULAR EMERGENCY
requires emergent systemic acyvlovir
what should you do if you have a patient with an autoimmune disorder or systemic infection that presents with a red eye, decreased vision, photophobia or floaters?
refer to ophtho
