Download Diabetic Retinopathy

DIABETIC RETINOPATHY
DIABETIC RETINOPATHY
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Definition.
Epidemiology.
Risk Factors.
Pathogenesis.
Signs & Symptoms.
Classification.
Investigations.
Complications.
Management.
Diabetic eye disease
refers to a group of eye problems that people
with diabetes may face as a complication of
diabetes. All can cause severe vision loss or
even blindness.
Diabetic retinopathy - most common cause of
blindness between ages 20 and 70 years.
Diabetes is associated with the
following ocular events :
• Corneal abnormalities.
• Glaucoma ( rubeotic glaucoma ).
• neovascularization.
• Cataracts… snowflake retinopathy in younger pts and
greater frequency and earlier onset of age related
cataract.
• Neuropathies.
• Diabetic Retinopathy.
Diabetic retinopathy causes retinal
vascular disease.
Other causes of RVD :
- Hypertensive retinopathy.
- sickle cell retinopathy.
- Retinopathy of prematurity.
- central and branch retinal artery occlusion.
- Central and branch retinal vein occlusion.
- Abnormal retinal blood vessels.
The Retina
• What is Retina?
Structure that lines the inside of the globe behind ora
serrata.
• 2 major layers:
- Inner neurosensory retina (NSR): transparent, light
sensitive membrane.
- Outer retinal pigment epithelium (RPE).
• Retinal blood supply:
From central retinal artery and choroidal circulation.
Retinal Histology
Sclera
Outer
Plexiform layer
Choroid
Bipolar cells
RPE
Photoreceptor
outer segments
Inner
plexiform layer
Ganglion cells
Photoreceptor
inner segment
Nerve fiber
layer
Retinal Anatomy
• - DM 1 (IDDM) loss of insulin secretion
mostly in young people.. Onset is relatively
acute and retinopathy begins to appear
about 5 years after onset.
• - DM 2 (NIDDM) pt may retain some
insulin secretion but develop resistance to
its action. It occurs in older age group.
• Bcoz DM2 present several yrs prior to
diagnosis, retinopathy may be found at
predentation.
RISK FACTORS:
1. Duration of diabetes
2. Poor control of Diabetes
3. Hypertension
4. Nephropathy
6. Obesity and hyperlipidemia
7. Smoking
8. Pregnancy
Pathogenesis
Microangiopathy which has features
of both microvascular leakage and
occlusion
Microvascular leakage
Loss of pericytes results in distention of
weak capillary wall producing
microaneurysms which leak.
Blood-retinal barrier breaks down causing
plasma constituents to leak into the retina
– retinal oedema, hard exudates
Microvascular occlusion
Basement membrane thickening,
endothelial cell damage, deformed RBCs,
platelet stickiness and aggregation
Vascular Endothelial Growth Factor
(VEGF) is produced by hypoxic retina
VEGF stimulates the growth of shunt and
new vessels
Pathogenesis :
Too much sugar in your blood can damage the
tiny blood vessels (capillaries) that nourish the
retina.
This can result in diabetic retinopathy and vision
loss.
Elevated blood sugar levels can also affect the
eyes' lenses. With high levels of sugar over long
periods of time, the lenses can swell, providing
another cause of blurred vision.
Response to Hypoxia:
• More extensive retinal hypoxia triggers compensatory
mechanisms within the eye to provide enough oxygen
to tissues:
•
• Venous caliber abnormalities, such as
• venous beading, loops, and dilation.
• Intraretinal microvascular abnormalities (IRMA)
represent either new vessel growth or remodeling of
preexisting vessels through endothelial cell
proliferation within the retinal tissues to act as shunts
through areas of nonperfusion.
• Further increases in retinal ischemia trigger the
production of vasoproliferative factors :
– neovascularization at border of perfused and
unperfused => fragile &highly permeable vessels
.These delicate vessels are disrupted easily by
vitreous traction, which leads to hemorrhage into
the vitreous cavity or the preretinal space.
– Fibrovascular changes & traction => retinal edema,
retinal heterotropia and retinal detachments.
History – symptoms
it's possible to have diabetic retinopathy and not know it. In fact,
it's uncommon to have symptoms in the early stages of diabetic
retinopathy.
As the condition progresses, diabetic retinopathy symptoms may
include:
• Spots or dark strings floating in your vision
(floaters)
• Blurred vision
• Fluctuating vision
• Dark or empty areas in your vision
• Poor night vision
• Impaired color vision
• Vision loss
• Diabetic retinopathy usually affects both eyes.
Simulation of defective vision as experienced by a
Diabetic whose vision has been affected by Diabetic
retinopathy
Normal
Defective
Signs on Examination:
• Microaneurysms (Earliest , red or yellowish
dots).
– Earliest clinical sign of diabetic retinopathy
– Secondary to capillary wall outpouching due to
pericyte loss
– Appear as small red dots in the superficial
retinal layers
– Fibrin and RBC accumulation in the
microaneurysm lumen
– Rupture produces blot/flame hemorrhages
– May appear yellowish in time as endothelial cells
proliferate and produce basement membrane
• Dot and blot hemorrhages
• Occur as microaneurysms rupture in the deeper layers of the
retina
• (similar to microaneuryms if they are
small, distinguish by fluorescein angio).
• Flame-shaped hemorrhages - Splinter
hemorrhages, superficial.
• Retinal edema and hard exudates.
Caused by the breakdown of the blood-retina barrier,
allowing leakage of serum proteins, lipids, and protein
from the vessels.
• Cotton-wool spots.
.Nerve fiber layer infarction from occlusion of
precapillary arterioles
.Fluorescein angiography - No capillary perfusion
• Intraretinal microvascular abnormalities
– Remodeled capillary beds without proliferative
Cotton-wool spots
hard exudate
Flame-shape hemorrhage
Classification of DR
International Clinical DR Disease Severity Scale


No apperant retinopathy.
non-proliferative DR (NPDR)
Mild
Moderate
Severe

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Proliferative DR (PDR)
significant macular oedema
- May exist by itself or along with NPDR and PDR
Mild NPDR
• Microaneurisms only
• (earliest clinically detectable lesion)
Moderate NPDR
• Microaneurysms
and/or dot and blot
hemorrhages in at
least 1 quadrant
• Soft exudates
(Cotton wool spots)
• Venous beading or
IRMA (intraretinal
microvascular
abnormalities)
IRMA
Mild and Moderate Non- proliferative DR
was previously known as Background DR
Severe NPDR
Any one of the following 3 features is present
• Microaneurysms and intraretinal
hemorrhages in all 4 quadrants
• Venous beading in 2 or more quadrants
• Moderate IRMA in at least 1 quadrant
Known as the 4-2-1 rule
Proliferative DR
(PDR)
Characterized by
Proliferation of
new vessels from
retinal veins
• New vessels on
the optic disc
• New vessels
elsewhere on the
retina
Proliferative DR
NVD
2. International Clinical Diabetic Macular
Edema (DME) Disease Severity Scale:
• DME absent:
No retinal thickening or hard
exudates (HE)present in the
posterior pole.
• DME present:
Some retinal thickening or hard
exudates (HE) present in the
posterior pole.
• If DME present, it can be categorized as
follows:
- Mild DME:
Some retinal thickening or HE present in the
posterior pole but distant from the center of
macula.
- Moderate DME:
Retinal thickening or HE approaching the
center of the macula but not involving its
center.
- Severe DME:
Retinal thickening or HE involving the center
of the macula.
Diabetic Macular Edema
COMPLICATIONS OF DIABETIC
RETINOPATHY
• Vitreous hemorrhage
• Tractional retinal detachment
• Rubeosis Iridis
• Glaucoma
• Blindness
Vitreous Hemorrhage
SUBHYALOID HEMORRHAGE
Tractional retinal detachment
Rubeosis Iridis
Neovascular Glaucoma
• Complication of rubeosis iridis
• New vessels cause angle closure
• Mechanical obstruction to aqueous outflow
• Intra ocular pressure rises
• Pupil gets distorted as iris gets pulled
• Eye becomes painful and red
• Loss of vision
Blindness
• Non-clearing vitreous hemorrhage
• Neovascular glaucoma
• Tractional retinal detachment
• Macular ischemia
PREVENTION OF COMPLICATIONS
• By early institution of appropriate treatment
• This requires early detection of DR in its
asymptomatic treatable condition
• By routine fundus examination of all
Diabetics (cost effective screening)
• And appropriate referral to ophthalmologist
Screening
Type 1 diabetics:
First screen 5 years after onset, then
annually.
Type 2 diabetics:
First screen upon diagnosis and then
annually.
Mild and Moderate NPDR
- No specific treatment for retinopathy
- Good metabolic control to delay
progression
- Control of associated Hypertension,
Anemia and Renal failure
Severe and very severe NPDR
–
Close follow up by Ophthalmologist
Clinically significant macular oedema
- Laser photocoagulation to minimise risk of
visual loss
Proliferative DR
Retinal laser photocoagulation as per the
judgment of ophthalmologist (in high risk eyes)
─
─ It converts hypoxic retina (which produces
ANGIOGENIC factors) into anoxic retina (which
can’t)
Referral to Ophthalmologist
• Visual Symptoms
– Diminished visual acuity
– Seeing floaters
– Painful eye
• Fundus findings
- Macular oedema/hard exudates close to fovea
- Proliferative DR
- Vitreous hemorrhage
- Moderate to severe and very severe NPDR
- Retinal detachment
- Cataract obscuring fundus view
Referral to Ophthalmologist
• Presence of Risk Factors
- Pregnancy
- Nephropathy
DIRECT OPHTHALMOSCOPY
• Examination of the fundus of the eye
• To screen for Diabetic Retinopathy
• After dilatation of both eyes with %0.5
tropicamide
View of the retina through an
ophthalmoscope
Normal fundus views of Right
and left eye
Mild NPDR – Microaneurysms, Dot and
Blot hemorrhages
Moderate NPDR
Moderate NPDR with CSME
Circinate retinopathy – Hard exudates in a
ring around leaking aneurysms
Age related Macular degeneration: Note the
drusen. Not to be confused with Hard exudates. There
are no microaneurysms or dot/blot hemorrhages.
DRUSEN
Severe NPDR
• Cotton wool patches
• Hemorrhages - 4 quadrants
With CSME
Very severe NPDR
-Venous beading
Cotton-wool patches,
venous segmentation
- scars of laser spots
- Absorbing hemorrhages
CSME –
in
Different
Stages of
NPDR
Proliferative DR – New vessels elsewhere on
the retina along the supero-temporal vessels
PDR – New vessels on disc
PDR – New vessels on disc and new vessels
elsewhere on retina
PDR – with vitreous hemorrhage
Vitreous bleed
Vitreous Hemorrhage
Tractional retinal
detachment
Fibro-vascular
proliferation
Thank you!