What are the
ocular complications of DM
?
-Refractive changes
-Cataract formation
-Diabetic retinopathy
>>>Leading cause of blindness in working-age Americans
>>>Blindness 25x more likely in patient with DM
How common is
diabetic retinopathy
in patients with
type 1
and
type 2 patients
?
Type 1 DM
: 23% after 5 years, 80% after 15 years.
Type 2 DM
: Slightly lower prevalence than T1DM. Many present with retinopathy at time of diagnosis.
What is the
pathogenesis of diabetic retinopathy
?
Diabetic retinopathy is a disease of blood vessels.
2 basic changes within retinal vessels:
-Abnormal permeability
-Vascular occlusion with ischemia and subsequent neovascularization
Metabolic effects of chronic hyperglycemia causes:
-Impaired autoregulat
What are the 2 major
classifications of diabetic retinopathy
?
Nonproliferative retinopathy (95%)
:
-Earliest stage of diabetic retinopathy
-Commonly described as "background retinopathy"
-Progresses slowly (good thing)
Proliferative retinopathy
:
-Advanced stage - can advance RAPIDLY to blindness
What are the
characteristics of nonproliferative diabetic retinopathy
?
Characterized by
variable display of the following
:
-Cotton wool spots (nerve-fiber layer infarcts)
-Intraretinal hemorrhages (dot and blot hemorrhages - not flame hemorrhages)
-Hard exudates
-Microvascular abnormalities primarily in macula and posterior
What causes
visual loss
in patients with
nonproliferative diabetic retinopathy
?
Visual loss in NPDR is primarily through the development of
macular edema
: can't visualize on fundoscopic exam.
-Retinal thickening and edema involving macula.
How can nonproliferative diabetic retinopathy be
further classified
and what are the significance of these classifications?
Can be further classified as
mild, moderate, severe, and very severe
.
-Stratification impacts risk of progression to proliferative retinopathy.
>>>Influences follow-up intervals and treatment strategies.
>>>One year risk of progression to proliferative r
What are the major characteristics of
proliferative diabetic retinopathy
?
Marked by
presence of
:
-
Neovascularization
arising from the disc and/or retinal vessels
-Consequence of neovascularization
>>>Preretinal and vitreous hemorrhage
>>>Subsequent fibrosis
>>>Traction retinal detachment
What causes
visual loss/changes
in patients with
proliferative diabetic retinopathy
?
Acute visual loss in PDR
may occur if bleeding into vitreous blocks light path to retina - often reabsorbed and vision clears.
Permanent loss of vision may occur through
:
-Retinal detachment
-Ischemia of macula
-Combination of above
How can
proliferative diabetic retinopathy
be further classified?
Proliferative DR can be classified as
early, high-risk, and severe
.
75% five-year risk of progression from early to high-risk stages.
How can you diagnose
proliferative retinopathy
?
May be diagnosed by fundus examination, but
fluorescein angiography
is useful to document capillary non-perfusion and leakage from new blood vessels.
On which
4 variables
are new vessels in
proliferative retinopathy classified
?
New vessels are categorized by 4 variables:
-Presence
-Location
-Severity
-Associated hemorrhagic activity
When can
macular edema
develop in retinopathy and how does it present?
Macular edema can develop at
all stages of retinopathy
.
Typically presents with
gradual onset of blurring of near and distant vision
in patients who have
other evidence of microvascular eye disease
.
How can you visualize
macular edema on a patient
?
Specialized techniques necessary to visualize:
-Fluorescein angiography
-Optical coherence tomography (OCT)
What is seen on
optical coherence tomography (OCT)
?
produces a
cross-sectional view of the retina
similar to a pathologic specimen.
>>> Can look at retinal layers and objectively measure how thick the layers are.
>>>Used to detect/visualize macular edema.
How is
diabetic retinopathy treated
?
Prevention is ideal!!
-Tight control of glucose: reduces risk of newly diagnosed retinopathy, reduces progression of existing retinopathy, reduction in progression to severe NPDR and proliferative retinopathy.
Nonproliferative diabetic retinopathy
: Obser
What is the role of
laser treatment
in treating diabetic macular edema?
Used in treatment of
diabetic macular edema
:
-Argon laser used to seal off leaking vessels and microaneurysms by burning them (focal treatment)
-Antiangiogenic therapy (intravitreal ranibizumab (Lucentis) therapy may also be effective in reducing diabeti
What is the role of
laser treatment
in treating
advanced diabetic retinopathy and neovascularization
?
1000-2000 laser burns around peripheral retina with pan-retinal photocoagulation.
-Reduction of metabolic oxygen requirement of retina or descrution of vascular endothelial growth factor (VEGF)-secreting cells promotes regression of neovascular tissue.
Si
How is a
vitrectomy
used to treat diabetic retinopathy?
#NAME?
What ocular abnormalities are
directly related to HTN
?
These abnormalities are referred to as
hypertensive retinopathy
:
-Progressively increasing retinal microvascular changes.
What are consequences of
hypertension
on the eye?
Can have hypertensive retinopathy (progressively increasing retinal microvascular changes).
HTN may also accelerate non-vascular eye disease:
-Age-related macular degeneration
-Glaucoma
What are the 2 classifications of
hypertensive retinopathy
?
1. Changes due to arteriolar sclerosis
2. Changes due to elevated blood pressure
What is
arteriolar sclerosis
and what are the characteristic features?
Thickening and sclerosis of arterioles associated with aging is accelerated by prolonged systemic HTN.
Thickening of walls of retinal arterioles results in characteristic ophthalmologic features:
-Increase in light reflex of arteriole (as walls of arterio
Describe the
course and progression of arteriolar sclerosis
?
Normal eye
: retinal arterioles are transparent tubes with light reflex from convex wall arteriole.
As arteriolar sclerosis causes thickening of vessel wall, central light reflex increases in width.
Eventually occupies most of width of vessels =
Copper wi
How/why does AV nicking occur with arteriolar sclerosis?
Arterioles and veins share common sheath within retinal tissue.
With arteriolar sclerosis, changes in caliber of vein may occur because of compression and constriction at A/V crossing.
-Dilation of distal portion of vein and tapering of vein on either sid
What are
ocular consequences
of
acute elevation of blood pressure
?
Acute rise in blood pressure results in constriction of arterioles.
Severe acute rise (usually SBP>200 and DBP>120) causes fibrinoid necrosis of vessel wall, resulting in:
-Exudates
-Cotton wool spots
-Flame-shaped hemorrhages
-Subretinal fluid
What is the ocular-related definition of
malignant HTN
?
Acute rise of blood pressure that causes
papilledema
. (hypertensive retinopathy)
How can you tell if an exudate on fundoscopic exam is due to hypertension or diabetes?
Can't tell if exudate is hypertensive or diabetic inspection >>> must go by history.
What are the 3 classifications of
hypertensive retinopathy
?
Mild
: retinal arteriolar narrowing related to vasospasm, arteriolar wall thickening, or opacification and AV nicking.
Moderate
: hemorrhages (flame or dot), cotton wool spots, hard exudates, and microaneurysms.
Severe
: some or all of the above PLUS papi
What is the
modified scheie classification
for
hypertensive retinopathy
?
Grade 0
: No changes
Grade 1
: Barely detectable arterial narrowing
Grade 2
: Obvious arterial narrowing with focal irregularities
Grade 3
: Grade 2 plus hemorrhages and/or exudates
Grade 4
: Grade 3 plus disc swelling
How should
hypertensive retinopathy be managed
?
Presence of hypertensive retinopathy should sever as an additional stimulus to ensure adequate control of HTN.
With good control, retinopathy may regress.
What are ocular physiologic changes that occur in
pregnancy
?
#NAME?
What
pathologic ocular conditions
can be seen in
pregnancy
?
#NAME?
What are possible ocular complications in patients with
sickle cell anemia
?
Intravascular sickling, hemolysis, hemostasis, and thrombosis lead to arteriolar occlusion (mirrors what we see in diabetic retinopathy).
Inadequate perfusion of retina can stimulate retinal neovascularization (and changes similar to DMR).
-Patients shoul
What are ocular changes related to
thyroid disease
?
Thyroid-related orbitopathy of Graves disease:
-Autoantivody-mediated enlargement of extraocular muscles, orbital fat, and lacrimal gland.
-Findings:
>>>Retraction of upper and lower eye lid
>>>Upper lid lag on downgaze
>>>Exophthalmos: protrusion of glob
What are
physical exam signs
seen in patients with
Graves' opthalmopathy
?
NO SPECS"
0=No signs or sxs
1=Only signs (lid retraction or lag), no sxs
2=Soft tissue involvement (periorbital edema)
3=Proptosis
4=Extraocular muscle involvement (diplopia)
5=Corneal involvement
6=Sight loss
How can
malignancy
affect the eyes?
Side effects of treatment for malignancy (chemo/radiation):
-Radiation of tumors of vicinity of eye: cataracts, delayed retinal vasculopathy and optic neuropathy.
-Chemotherapeutic agents: cystosine arabinoside (superficial keratitis), vincristine (optic
What are the characteristics of
AIDS retinopathy
?
Microthrombi from antigen-antibody complexes and fibrin cause occlusions in retinal arterials resulting in
cotton wool spots
: due to antigen-antibody complexes causing occlusions and micro-infarcts.
Intra-retinal hemorrhages
What are the characteristics of
cytomegalovirus (CMV) retinitis
?
AIDS-defining illness:
-Characterized by sectoral hemorrhagic necrosis of retina, typically along a retinal vessel.
-Disease progresses over weeks to months - results in total atrophy of affected retina.
How can
systemic lupus erythematosus
affect the eye?
Any structure of the eye can be involved in SLE.
-Most common = Keratoconjunctivitis sicca as a result of secondary Sjogren's syndrome
-Next most common = retinal vasculopathy in form of cotton wool spots
-Less commonly - optic neuropathy, episcleritis, s
What are the
2 major categories of systemic causes of uveitis
?
1.
Infections
: herpes virus, CMV, toxoplasmosis, syphilis, tuberculosis, cat-scratch disease, west nile virus, ebola virus, zika virus
2.
Immune-mediated diseases
: spondyloarthritis, sarcoidosis, psoriatic arthritis, inflammatory bowel disease, multiple