Download Dr Ziai chronic visual loss_compressed

Chronic Visual
Disturbance and Visual
Loss
Setareh Ziai
April 2nd, 2009
[email protected]
QUICK review
Basic Anatomy
Where is the problem?
LMCC Objectives



Pre-retinal:

cornea (dystrophy, scarring, edema)

lens (age-related, traumatic, steroid-induced)

glaucoma
Retinal:

DM (diabetic retinopathy, macular edema)

vascular insufficiency (arterial or venous occlusion)

tumours

macular degeneration
Post-retinal:

anterior to optic chiasm (if optic nerve = monocular)
• compressive optic neuropathy (intracranial masses, thyroid eye disease)
• toxic/nutritional (nutritional deficiencies, alcohol/tobacco amblyopia)

optic chiasm lesions (pituitary adenoma)
Where is the problem?



Pre-retinal:

cornea (dystrophy, scarring, edema)

lens (age-related, traumatic, steroid-induced)

glaucoma
Retinal:

DM (diabetic retinopathy, macular edema)

vascular insufficiency (arterial or venous occlusion)

tumours

macular degeneration
Post-retinal:

anterior to optic chiasm (if optic nerve = monocular)
• compressive optic neuropathy (intracranial masses, thyroid eye disease)
• toxic/nutritional (nutritional deficiencies, alcohol/tobacco amblyopia)

optic chiasm lesions (pituitary adenoma)
Diagnosis based on:
- focused ophthalmological history
-
-
exam: … start with gross examination
-
-
monocular vs. binocular
acute vs. chronic
painful vs. painless
VA
slit lamp biomicroscopy +/- fluorescein
dilated fundus examination
VF testing
fluorescein angiography +/- other tests
 **Remember

for exam:
sometimes, chronic visual loss in ONE eye is
noted incidentally some time later due to
occlusion of normal eye…: CHRONIC LOSS
OF VISION CAN PRESENT ACUTELY!!
Corneal Causes
-
dystrophy
- scarring
- edema
The Cornea
- allows light to enter the
eye
- provides most of the eye’s
optical power
- 0.5-0.8 mm thick
- transparent due to its
uniformity, avascularity
and deturgescence
Epithelium
Stroma
Endothelium
Corneal Dystrophies
-
rare inherited disorders
-
progressive, usually bilateral
-
can affect any of the three layers of the
cornea
-
affect transparency
-
age at presentation: first to fourth decades
Corneal Dystrophies
-
divided into:
-
anterior dystrophies:
- epithelium
- may present with recurrent corneal erosions
-
stromal dystrophies:
- usually present with visual loss
- if very anterior, can cause erosions and pain
-
posterior dystrophies:
- endothelium
- vision loss secondary to edema (endothelial dysfx)
Corneal Scarring
-
multiple causes:
-
trauma
-
infectious (eg., herpes)
-
post-surgical
Corneal Edema
-
most often caused by dysfunction of the
corneal endothelium:
-
dystrophy
-
trauma
-
infectious (eg., herpes)
-
post-surgical
Corneal
Transplantation
If the corneal stroma opacifies due to
trauma or infection, or if there is
swelling or an irregularity of the
surface of the cornea, light cannot
properly reach the retina.
In some cases, a cornea from a
deceased donor can be transplanted.
Corneal Transplantation
Lens-Related Causes
(cataract)
age-related
- traumatic
- steroid induced
-
The Lens
- biconvex, avascular,
transparent structure
- sits inside a thin
capsule, attached to the
ciliary body by the
zonules
- provides the
remainder of the eye’s
optical power (along
with the cornea)
Lens
 cataracts
are due to the opacification of
this normally clear structure
Age-Related Cataract
-
-
often affect the nucleus of the lens first:
-
yellowing, followed by a browning of the lens
-
eventually, liquefaction
causes myopic changes (increased
refractive index of the lens)
Traumatic Cataract
-
most common cause of unilateral cataract
in young individuals
-
most often caused by direct penetrating
injury to the lens
-
can also be caused by:
-
concussion
-
ionizing radiation to ocular tumours
-
infrared radiation (glassblowers)
Steroid-Induced Cataract
-
both systemic and topical steroids can be
the culprits
-
posterior part of lens affected first
-
children may be more susceptible
-
if lens changes develop, dose should be
reduced to the minimum necessary
-
early opacities may regress with
discontinuation of therapy
Glaucoma
Glaucoma
 disease
of the optic nerve, often
caused by an increase in intraocular
pressure due to poor drainage of
aqueous from the trabecular
meshwork…
Glaucoma
 if
left untreated, glaucoma can lead to
permanent damage to the optic nerve
and resultant visual field loss
 can progress to blindness
Glaucoma
 by
definition, glaucoma is a trimodal
disease, characterized by:
increased IOP
 optic nerve changes
 visual field changes

Goldmann Applanation Tonometer
Glaucoma
 classification:



primary: open-angle, angle-closure
secondary: inflammatory, traumatic,
neovascular, steroid-induced etc…
congenital
Risk Factors for Glaucoma
 age
 african-american
 high
IOP
 family history
 myopia
heritage
Symptoms of Glaucoma
 often
asymptomatic
 with late disease, constriction of
peripheral, and later central visual field
 with very high IOP, can have blurry
vision and halos around lights
Glaucoma: Optic Nerve
Changes
 increased
cup:disc ratio
 thinning of neural rim
 progressive loss of nerve fiber layer
 flame hemorrhages on disc
Primary Open Angle
Glaucoma
 most
common (90%)
 usually bilateral (can be asymmetric)
 prevalence increases with age
 angle is open, eye is quiet
 increased resistance to aqueous drainage
at the level of the trabecular meshwork is
thought to be the main pathophysiologic
feature
Treatment options
 goal
is to stabilize the IOP to protect
the optic nerve against further damage
 options:



drops
laser
surgery
Glaucoma - Medications
 mechanism

of action:
decrease aqueous production:
• beta blockers: timolol
• alpha agonists: brimonidine
• carbonic anhydrase inhibitors: diamox

increase aqueous outflow:
• miotics: pilocarpine
• epinephrine
• prostaglandin analogs: latanoprost
Glaucoma - Lasers
 usually
when medical management
fails


ALT (argon laser trabeculoplasty), SLT
(selective laser trabeculoplasty): for open
angle glaucomas
peripheral iridotomy: for angle-closure
glaucomas
 high
success rate
Glaucoma - Surgery
 usually
when medical management and
laser treatments fail



trabeculectomy: sub-conjunctival shunt of
aqueous
drainage devices (valves)
cyclodestruction: last resort – destruction
of ciliary body
Where is the problem?



Pre-retinal:

cornea (dystrophy, scarring, edema)

lens (age-related, traumatic, steroid-induced)

glaucoma
Retinal:

DM (diabetic retinopathy, macular edema)

vascular insufficiency (arterial or venous occlusion)

tumours

macular degeneration
Post-retinal:

anterior to optic chiasm (if optic nerve = monocular)
• compressive optic neuropathy (intracranial masses, thyroid eye disease)
• toxic/nutritional (nutritional deficiencies, alcohol/tobacco amblyopia)

optic chiasm lesions (pituitary adenoma)
THE RETINA
- neural tissue lining
the inside of the eye
- converts the visual
image into a
neurochemical
message and sends it
to the brain
- is made up of 10
anatomic layers
Diabetes
diabetic retinopathy
- diabetic macular edema
-
Diabetic Retinopathy
microangiopathy
affects pre-capillary arterioles, capillaries
and post-capillary venules
features of:
microvascular occlusion
leakage
clinically, can be divided into:
background DR (nonproliferative)
preproliferative DR
proliferative DR
Diabetic Retinopathy: Epidemiology
239 million people by 2010
doubling in prevalence since 1994
diabetes will affect:
28 million in western Europe
18.9 million in North America
138.2 million in Asia
1.3 million in Australasia
•
#1 cause of blindness in patients 20-64 yrs
•
prevalence increases with duration of diabetes and
patient age
rare to find DR in children < 10 yrs, regardless of duration
risk of developing DR increases after puberty
Epidemiology
Wisconsin Epidemiologic Study of Diabetic Retinopathy
Between 1979-1980
1210 patients with Type 1
1780 patients with Type 2
predominantly white population
After 20 yrs, DR present in:
99% of Type 1
60% of Type 2
WESDR: Frequency of retinopathy in
subjects with type 1diabetes
WESDR: Frequency of retinopathy in
subjects with type 2 diabetes
Diabetic Retinopathy: Risk Factors
duration of diabetes: most important risk
factor
poor metabolic control
pregnancy: can be associated with rapid
progression
HTN
nephropathy
smoking
obesity
hyperlipidemia
Classification of Diabetic Retinopathy
Classified into 2 stages
Nonproliferative Diabetic Retinopathy (NPDR)
early stage
also known as background DR (BDR)
further categorized based upon extent of DR
mild, moderate, severe, very severe
Proliferative Diabetic Retinopathy (PDR)
more advanced stage
•
***Macular edema
• May be present at any stage of DR
NPDR
typically asymptomatic
fluctuating visual acuity:
fluctuating blood sugar
decreased visual acuity:
CSME
macular ischemia
review these patients annually
Mild NPDR
Moderate NPDR
Severe NPDR
Proliferative Diabetic Retinopathy
more likely to become
symptomatic than early
NPDR
may have decreased
vision, sudden vision loss,
floaters, cobwebs, flashes,
dull eye ache
PDR can also affect visual
function by affecting the
macula with resulting
macular ischemia and/or
edema
Proliferative DR
affects 5-10% of the diabetic population
neovascularization is the hallmark
NVD: neovascularization of the disc
NVE: neovascularization elsewhere
new vessels are not only extremely fragile
(intraretinal or vitreous hemorrhage), but
often associated with fibrous proliferation,
leading to an increased risk of tractional retinal
detachment
Advanced PDR

Tractional retinal
detachment
resulting from
contraction of
the fibrovascular
proliferative
tissue on the
retina
Panretinal Photocoagulation for High-risk
PDR

goal is to induce
involution (or at
least arrest) of new
vessels by creating
areas of retinal
ischemia
 1200-3000 burns
 4 sessions
Vitrectomy for Vitreous
Hemorrhage / TRD
Diabetic Macular Edema (DME)
retinal edema threatening or involving the
macula
diagnosis is made by slit-lamp exam,
confirmed by fluorescein angiography and/or
OCT
important observations include:
location of retinal thickening relative to the
fovea
presence and location of exudates
DME and CSME
Treatment of CSME

argon laser application

intravitreal steroid injection

intravitreal anti-VEGF injection

pars plana vitrectomy
Ophthalmological Follow-Up

Diabetic Screening
Type 1 diabetics:
Dilated funduscopic exam (DFE) 5 yrs after diagnosis
Newly diagnosed patients with Type 1 diabetes rarely
have retinopathy during the first 5 yrs
Type 2 diabetics:
Type 2 diabetics typically diagnosed yrs after initial
onset
DFE at the time of diagnosis
Significant portion of newly diagnosed Type 2
diabetics have established DR at the time of
diagnosis
Vascular Insufficiency
arterial occlusions (CRAO, BRAO)
- venous occlusions (CRVO, BRVO)
-
CRAO
CRAO
 most
of the retina is supplied by the
central retinal artery (branch of the
ophthalmic artery, which is the first branch
of the ICA)
 if this supply is interrupted (embolus,
thrombosis, inflammation, vasculitis or
compression), the retina becomes
ischemic
 irreversible damage occurs after
approximately 90 minutes
CRAO
presentation is with sudden and
profound loss of vision
RAPD is present
orange reflex from the choroid stands
out at the fovea, and contrasts with the
surrounding pale retina (cherry-red
spot)
must r/o temporal arteritis
CRAO
most commonly the result of
atherosclerosis (thrombosis) but may
also be caused by calcific emboli
often in older patients, with a hx of
arteriosclerosis
may have had a hx of amaurosis fugax
(transient visual loss)
CRAO
 OPHTHALMOLOGIC EMERGENCY!!
 treatment:
decrease IOP
paracentesis
ocular massage
 goal: to send the embolus distally
 **remember to r/o giant cell arteritis! (ESR, CRP, plt)
 poor prognosis: 60%  20/400
BRAO
BRAO
sudden and profound altitudinal or
sectoral visual field loss
similar causes as CRAO
identify and treat associated medical
conditions (HTN, DM,
hypercholesterolemia, smoking,
vasculitis etc…)
BRAO
retinal cloudiness in ischemic area
+/- visible embolus
 also has a poor prognosis, unless the
obstruction can be dislodged within a
few hours
CRVO
CRVO
 thrombosis
of the central retinal vein
sudden loss of vision in affected eye
severity of symptoms varies…
non-ischemic: 75%
Ischemic
most characteristic finding: retinal
hemorrhages
CRVO
underlying associations
advancing age
systemic conditions: HTN, DM, smoking,
obesity, hyperlipidemia
glaucoma
inflammatory diseases: sarcoidosis, Behcet
disease
thrombophilic disorders:
hyperhomocysteinaemia, antiphospholipid
antibody syndrome
CRVO
Treatment:
treat associated medical conditions
decrease IOP if elevated
pan-retinal photocoagulation
(laser) if:
• neovascularization (iris, angle,
retina)
• …especially if ischemic CRVO
BRVO
BRVO
 thrombosis
of a branch of the central
retinal vein
visual loss depends on the amount of
macular drainage compromised by the
occlusion (peripheral occlusions may be
asymptomatic)
characteristic findings in one sector of the
retina:
dilatation and tortuosity of veins
retinal hemorrhages
retinal/macular edema
BRVO
obstruction often at arterio-venous
crossings: arteries and veins share
adventitial sheath… thickening of the
arteriole (arteriosclerosis) compresses the
vein, eventually causing an occlusion
often associated with:
hypertension (75%)
diabetes (10%)
BRVO
prognosis: depends on amt of venous
drainage involved by the occlusion and
severity of macular ischemia: within 6 mos,
about 50% of eyes have a VA of 20/30 or
better
main complications:
chronic macular edema
neovascularization
laser photocoagulation may be helpful in
above cases
Retinal Tumours
 ocular

tumours:
ciliary body:
• melanoma

choroid:
• melanoma
• hemangioma
• metastases


primary ocular lymphoma
retina and optic nerve:
• retinoblastoma
• astrocytoma
• hemangioma
Choroidal Melanoma
 most
common primary intraocular
tumour in adults
 presentation usually in 6th decade:


asymptomatic vs. visual field defect and/or
decreased visual acuity
signs:
 raised, usually pigmented lesion visible at
the back of the eye
 may be associated with retinal detachment
 optic nerve may be involved
Choroidal Melanoma
 treatment:

consider size, location, activity of tumour,
state of fellow eye, general health/age of pt,
pt’s wishes/fears
• brachytherapy
• external radiotherapy
• transpupillary thermotherapy
• local resection
• enucleation
• exenteration
• palliative (may include chemo)
Choroidal Metastases
 …with
choroidal melanoma, don’t forget
general medical investigations!

mets TO the choroid:
• most frequently from bronchus in both sexes
and the breast in women, rarely kidney or GI


CXR, rectal exam, mammography
mets FROM the choroid:
• liver

hepatic u/s, GGT, ALP
• lungs (rarely affected before liver)

CXR
Choroidal Metastases
 usually
present with visual impairment
only IF tumour is near the macula
 signs:



fast-growing, creamy coloured lesion
most often in posterior pole
usually not very elevated (infiltrates laterally)
Choroidal Metastases
 treatment:





observe: if asxic or receiving systemic chemo
radiation: external beam or brachy
transpupillary thermotherapy
systemic therapy for the primary
enucleation: for painful blind eye
 prognosis

is poor…
median survival: 8-12 mos for all pts, 15-17
mos for those with breast ca
Retinoblastoma
 most
common malignant tumour of the eye
in childhood (1:20 000)
 mean age of presentation: 8 mos if
inherited, 25 mos if sporadic




60% present with leukocoria (white pupillary
reflex)
strabismus (20%)
occasionally: painful, red eye
if inherited: often bilateral
Retinoblastoma
 malignant
transformation of primitive
retinal cells before their final differentiation
 can
be caused by germinal mutations (can
be passed on to the next generation), or
can be sporadic (66% of cases)
Retinoblastoma
 this
is a clinical diagnosis, but CSF and
bone marrow should be examined to check
for metastatic disease if ON involved or if
there is evidence of extraocular extension
 rx:




small: cryotherapy, photocoagulation
medium: brachytherapy, external beam, chemo
large/advanced cases: chemoreduction + local
treatment, enucleation
metastatic disease: chemo (intrathecal if cells
in CSF)
Retinoblastoma
 prognosis:



depends on extent of disease at diagnosis
overall mortality ~ 5-15%
~ 50% of children with the germinal mutation
will eventually develop a second primary
tumour (eg., osteosarcoma of the femur or
pinealoblastoma)
Macular Degeneration
Macula
 1.5
mm in diameter
 central vision: BEST VISUAL ACUITY
 colour vision
 progressive destruction of the macular
area:
MACULAR DEGENERATION
Macular Degeneration
 most
common cause of irreversible
visual loss in the developed world
 exists in two forms:
non-exudative (dry) macular
degeneration
 exudative (wet) macular
degeneration

Non-exudative Macular
Degeneration
 lipid
products arising from
photoreceptor outer segments are
found under retina


can be seen with ophthalmoscope!
called « drusen »
Exudative Macular
Degeneration
 new
vessels from the choroid grow into
the sub-retinal space; form a subretinal neovascular membrane
 subsequent
hemorrhage into the subretinal space or even through the retina
into the vitreous is associated with
profound loss of vision
Macular Degeneration
 symptoms:

since fovea is responsible for fine visual
resolution, any disruption will cause
severe visual impairment
• blurry/reduced vision
• distorted vision (metamorphopsia)
• reduction (micropsia) or enlargement
(macropsia) of objects
• VF loss (scotoma)
Macular Degeneration
 rx:

non-exudative (usually slowly
progressive):
• no actual medical treatment
• use low vision aids
• high dose antioxidants MAY be
beneficial (eg., vitalux)
Macular Degeneration
 rx:

exudative (can be rapidly progressive and
devastating):
• intravitreal injections of anti-VEGF
factors: bevacizumab, ranibizumab
• photodynamic therapy (injection of
photosensitizer into systemic circulation
followed immediately by laser targeting
new vessels in macular area)
• combination of above treatments
Where is the problem?



Pre-retinal:

cornea (dystrophy, scarring, edema)

lens (age-related, traumatic, steroid-induced)

glaucoma
Retinal:

DM (diabetic retinopathy, macular edema)

vascular insufficiency (arterial or venous occlusion)

tumours

macular degeneration
Post-retinal:

anterior to optic chiasm (if optic nerve = monocular)
• compressive optic neuropathy (intracranial masses, thyroid eye disease)
• toxic/nutritional (nutritional deficiencies, alcohol/tobacco amblyopia)

optic chiasm lesions (pituitary adenoma)
OPTIC NERVE
 1.2
million cells

80 % visual fibres
 20 % pupillary fibres
 carries
visual
information from
the eye to the brain
OPTIC CHIASM
crossover
above
of nasal fibers
the pituitary
internal
carotids are just
lateral
from
optic chiasm:
optic
tract to the
lateral geniculate body
optic
radiation to the
primary visual cortex
Anterior to Optic
Chiasm
compressive optic neuropathies
- toxic/nutritional optic neuropathies
-
Compressive Optic
Neuropathies
 INTRACRANIAL

MASSES:
optic nerve glioma
• typically affects young women, end of first decade
• associated with NF-1

optic nerve sheath meningioma
• most frequent in middle-aged women
• unilateral, gradual visual impairment

any other orbital or chiasmal tumour
compressing any part of the optic nerve
 THYROID
EYE DISEASE
Thyroid Eye Disease
 may
occur in the absence of biochemical
evidence of thyroid dysfx
 autoimmune reaction (IgG Abs) causing:

inflammation of EOMs: pleiomorphic cellular
infiltration associated with increased secretion
of GAGs and osmotic imbibition of water
• muscles can become up to 8 times their original
size!!
 no
relation to severity of thyroid dysfx!
Thyroid Eye Disease
 main





findings: (not all are always present!)
soft tissue involvement
lid retraction
proptosis
optic neuropathy
restrictive myopathy
Thyroid Eye Disease
 vision

loss from:
exposure keratopathy
• due to severe proptosis resulting in incomplete lid
closure → chronically exposed cornea → corneal
ulceration & exposure keratopathy

optic neuropathy
• affects 5% of pts
• compression of ON or its blood supply by
congested (enlarged) EOMs
• can lead to severe, permanent visual impairment
• rx with steroids, surgery if needed
Toxic/Nutritional Optic
Neuropathies
 nutritional
deficiencies
 alcohol-tobacco amblyopia
Nutritional Deficiencies





pts with extremely poor diets, often in association
with alcohol-tobacco amblyopia
usually due to B12 deficiency in combination with
cyanide toxicity
symmetrical VF loss
if early, can be treated with high-dose vitamins
and restoration of « well-balanced diet »
eventually leads to optic atrophy and permanent
vision loss
Alcohol-Tobacco Amblyopia





affects heavy drinkers, cigar and pipe smokers: deficient in
protein and the B vitamins
symptoms: insidious, bilateral, progressive visual
impairment + dyschromatopsia
signs: symmetrical VF defect, may have pale (or normal)
discs
rx: 1000 units of hydroxocobalamin qweekly X 10 wks +
multivitamins + « well-balanced diet »
px:
 good in early cases if comply with rx
 advanced cases: optic atrophy and permanent visual
loss
Optic Chiasm Lesions
-
pituitary adenoma
Pituitary Adenoma
 presentation
usually in early adult life or
middle age
 symptoms:


h/a
visual symptoms: very gradual onset (often
not noticed by pt until very well-established)
• VF defect: usually, bitemporal hemianopia, worst in
the superior field, and extending inferiorly
• colour desaturation across vertical midline
• optic atrophy: in 50% of cases with field defects
caused by pituitary lesions
Pituitary Adenoma
 investigations:



MRI: coronal, axial and sagittal sections before
and after gadolinium injection
CT: demonstrates enlargement or erosion of
the sella
endocrinological investigation: PRL, FSH, TSH,
GH
Pituitary Adenoma
 treatment





options:
observation
medical: dopamine agonists (bromocriptine)
surgery
radiotherapy: often used as an adjunct
gamma knife stereotactic radiotherapy
Visual Field Defects
Merci