Diabetic Retinopathy Flashcards
What is diabetic retinopathy?
A progressive microangiopathy of the retinal blood vessels caused by chronic hyperglycemia
What is the most common cause of moderate to severe vision loss between ages 25 and 74 years?
Diabetic retinopathy
What are the two major layers of the retina?
1) Inner neurosensory retina (NSR)
2) Outer retinal pigment epithelium (RPE)
Where does the retinal blood supply come from?
1) Central retinal artery
2) Choroidal circulation
What is the pathogenesis of diabetic retinopathy?
Microangiopathy which has features of both microvascular leakage and occlusion
Loss of pericytes results in:
1) Distention of capillary wall
2) Disruption of the inner Blood-retinal barrier
Distention of the capillary wall causes __.
Microaneurysms
Disruption of the inner Blood-retinal barrier causes:
Plasma constituents to leak into the retina =
1) Retinal edema
2) Hard exudates
Hypoxic retinas produce:
VEGF (Vascular Endothelial Growth Factor)
What is the hallmark of proliferative diabetic retinopathy
New vessels
With time, the fibrous component of new vessels
contracts and results in:
Traction retinal detachment
Microvascular occlusion leads to:
1) Basement membrane thickening
2) Endothelial cell damage
3) Deformed RBCs
4) Platelet stickiness and aggregation
Early signs of non-proliferative diabetic retinopathy:
1) Microaneurysms
2) Dot and blot hemorrhages
3) Flame-shaped hemorrhages
4) Cotton-wool spots
5) Hard exudates
6) Edema
7) Venous changes (heading and looping)
8) Intraretinal microvascular abnormalities (IRMAs)
What is the EARLIEST clinical sign of diabetic retinopathy?
Microaneurysms
What do microaneurysms look like?
Small red dots in the superficial
retinal layers
A microaneurysm rupture produces:
Dot, blot, and flame shaped hemorrhages
What are dot and blot hemorrhages?
Microaneurysm ruptures in the deeper layers of the retina
What causes hard exudates?
Breakdown of the blood-retina
barrier = leakage of serum proteins and lipids from the vessels.
What causes cotton-wool spots?
Nerve fiber layer infarction from
occlusion of precapillary arterioles
What are intraretinal microvascular abnormalities?
Abnormal branching, sinuous shunt vessels that typically develop adjacent to areas of capillary non-perfusion
The International Clinical Diabetic Macular Edema (DME) Disease Severity Scale says that if diabetic macular edema us present, then that means:
There is some retinal thickening or hard exudates (HE) present in the posterior pole
Diabetic Macular Edema (DME) is categorized as:
1) Mild DME
2) Moderate DME
3) Severe DME
Mild DME is:
Some retinal thickening or hard exudates are present in the posterior pole but distant from the center of macula.
Moderate DME is:
Retinal thickening or hard exudates approaching the center of the macula but not involving its center.
Severe DME is:
Retinal thickening or hard exudates involving the center of
the macula.
What are the LATE signs of proliferative diabetic retinopathy?
1) Neovasclaization (NVDs,NVEs and NVIs)
2) Vitreous hemorrhages
3) Per retinal hemorrhages
4) Traction retinal detachment
5) Neovacular glaucoma
What is Rubeosis Iridis?
Neovascularization of the iris
Criteria for mild non-proliferative diabetic retinopathy?
Microaneurisms only
Criteria for moderate non-proliferative diabetic retinopathy?
1) Microaneurysms and/or dot and blot hemorrhages in more than 1 quadrant
2) Soft exudates (Cotton wool spots)
3) Venous beading in
one quadrant
Criteria for severe non-proliferative diabetic retinopathy?
1) Microaneurysms in 4 quadrants
2) Venous changes in 2 quadrants
3) IRMA in one quadrant
Proliferative diabetic retinopathy is characterized by:
1) Proliferation of new vessels from retinal veins
2) New vessels on the optic disc
3) New vessels elsewhere on the
retina
Treatment for Mild & Moderate NPDR?
No treatment, only control diabetes and other comorbidities.
Treatment for severe NPDR?
Follow up with opthamologist
Treatment for clinically significant Macular Edema?
1) Intra-vitreal anti-VEGF
2) Laser photocoagulation to minimize risk of visual loss
What is Circinate retinopathy?
Hard exudates in a ring around leaking aneurysms
Treatment for proliferative diabetic retinopathy?
1) Retinal laser photocoagulation
2) Anti-VEGF intravitreal injection, like Avastin
What is Neovascular Glaucoma a complication of?
Rubeosis iridis
What is Neovascular Glaucoma?
When new vessels cause angle closure and obstruct aqueous outflow = ↑ ICP
Neovascular glaucoma causes __ distortion as the __ gets pulled.
Pupil; Iris
Neovascular glaucoma symptoms include:
1) Pain
2) Redness
3) Loss of vision
Which conditions can cause blindness?
1) Non-clearing vitreous hemorrhage
2) Neovascular glaucoma
3) Tractional retinal detachment
4) Macular ischemia
