Diabetic retinopathy

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DIABETIC RETINOPATHYDr. Annamary StanislausMD,
MMED
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Applied Anatomy

• Retina, the innermost tunic of the eyeball, is a
  thin, delicate and transparent membrane.
• It is the most highly-developed tissue of the
  eye.
• It appears purplish-red due to the visual purple
  of the rods and underlying vascular choroid.

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• Retina extends from the optic disc to the ora
  serrata.
• Grossly it is divided into two distinct regions
• posterior pole and peripheral retina separated by
  the so called retinal equator.
• Retinal equator is an imaginary line which is
  considered to lie in line with the exit of the
  four vena verticose.

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• Posterior pole refers to the area of the retina
  posterior to the retinal equator.
• The posterior pole of the retina includes two
  distinct areas the optic disc and macula lutea
• Posterior pole of the retina is best examined by
  slit-lamp indirect biomicroscopy using 78D and
  90D lens and direct ophthalmoscopy

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Anatomy cont.

• Microscopic structure
• Retina consists of 3 types of cells and their
  synapses
• arranged (from without inward) in the following
  ten
• layers

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Photoreceptors

• Rods and Cones
• Rods and cones are the end organs of vision and
  are also known as photoreceptors.
• There are about 120 millions rods and 6.5
  millions cones.
• Rods contain a photosensitive substance visual
  purple (rhodopsin) and subserve the peripheral
  vision and vision of low illumination (scotopic
  vision).
• Cones also contain a photosensitive substance and
  are primarily responsible for highly
  discriminatory central vision (photopic vision)
  and colour vision.

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Diabetic Retinopathy

• Epidemiology
• RISK of developing DR
• Type I or IDDM 70
• Type II or NIDDM - 39
• Type II on insulin 70

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• Prevalence of the type of Diabetes
• Type 2 in 90 of diabetic patients
• Diabetic retinopathy - most common cause of legal
  blindness between ages 20 and 70 years.

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RISK FACTORS

• Duration of diabetes
• Poor control of Diabetes
• Hypertension
• Nephropathy
• Obesity and hyperlipidemia
• Smoking
• Pregnancy

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Pathogenesis

• Microangiopathy which has features of both
  microvascular leakage and occlusion
• Larger vessels may also be involved

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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

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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

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Classification of DR

• I. Non-proliferative DR (NPDR)
• Mild
• Moderate
• Severe
• Very severe
• Proliferative DR (PDR)
• III. Clinically significant macular oedema (CSME)
• - May exist by itself or along with NPDR
  and PDR

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Mild NPDR

• At least one microaneurysm - earliest clinically
  detectable lesion
• Retinal hemorrhages
• Hard or soft exudates

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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
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Mild and Moderate Non- proliferative DR was
previously known as Background DR
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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

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Very severe NPDR

• Any two of the features of the 4-2-1 rule is
  present

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Severe and Very severe Non-proliferative DR was
known as the Pre-proliferative DR
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Clinically significant Macular Oedema

• Retinal oedema close to fovea
• Hard exudates close to fovea
• Presents with dimness of vision
• By itself or along with NPDR or PDR

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CSME Hard exudates close to fovea and
associated retinal thickening
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Proliferative DR (PDR)

• Characterized by Proliferation of new vessels
  from retinal veins
• New vessels on the optic disc
• New vessels elsewhere on the retina

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Proliferative DR
NVD
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COMPLICATIONS OF DIABETIC RETINOPATHY

• Vitreous hemorrhage
• Tractional retinal detachment
• Rubeosis Iridis
• Glaucoma
• Blindness

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Vitreous Hemorrhage
SUBHYALOID HEMORRHAGE
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Tractional retinal detachment
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Rubeosis Iridis
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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

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Blindness

• Non-clearing vitreous hemorrhage
• Neovascular glaucoma
• Tractional retinal detachment
• Macular ischemia

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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

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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

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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
  cant)

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Screening protocol for Diabetic retinopathy

• Screening once in a 1 year
• Diabetics with normal fundus
• Mild NPDR
• Screening once in 6 months
• Moderate NPDR

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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

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Referral to Ophthalmologist

• Presence of Risk Factors
• - Pregnancy
• - Nephropathy

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DIRECT OPHTHALMOSCOPY

• Examination of the fundus of the eye
• To screen for Diabetic Retinopathy
• After dilatation of both eyes with 0.5
  tropicamide

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View of the retina through an ophthalmoscope
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Normal fundus views of Right and left eye
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Mild NPDR Microaneurysms, Dot and Blot
hemorrhages
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Moderate NPDR
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Moderate NPDR with CSME
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• Severe NPDR
• Cotton wool patches
• Hemorrhages - 4 quadrants

With CSME
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Very severe NPDR

• Venous beading
• scars of laser spots
• Absorbing hemorrhages

Cotton-wool patches, venous segmentation
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CSME in Different Stages of NPDR
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Proliferative DR New vessels elsewhere on the
retina along the supero-temporal vessels
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PDR New vessels on disc
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PDR New vessels on disc and new vessels
elsewhere on retina
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PDR with vitreous hemorrhage
Vitreous bleed
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Vitreous Hemorrhage
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Thank you!