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Flashcards in Diabetic Retinopathy 1 Deck (33):
1

DIABETIC RETINOPATHY

More common in what type of Diabetes ?

 Type I diabetics

2

DIABETIC RETINOPATHY
Risk factors?

  • Duration of diabetes
  • Poor metabolic control
  • Pregnancy
  • Hypertension
  • Nephropathy
  • Other things

3

Risk factors -Duration
Difference in duration in Diabetes leading to development of DR ?

 

Duration = most important risk factor

If a patient has been diagnosed before age 30, the incidence of DR after 10 years is 50% and after 30 years is 90%

Rarely develops within 5 years of onset or before puberty

About 5% of Type II diabetics have DR when they present to an ophthalmologist

4

Risk factors –Poor control

( Not as important as duration but still relevant)

  1. Benefit of good BSL control?
  2. Which type of Diabetes benefits more?
  3. What increase risk of proliferative DR?

  1. Good BSL control ⇒ prevent/delay development/progression of DR
    Problem: it is associated with increased risk of hypos
  2. Type I diabetics 
  3. Raised HbA1c (glycated haemoglobin) = increased risk of proliferative DR

 

5

Risk factors –Pregnancy
( may associate with Rapid progression of DR) 

Factors inflencing DR?

  • Poor control of BSL during pregnancy
  • Rapid control during early pregnancy
  • Pre-eclampsia (hypertension & ↑ protein in urine)
  • Fluid imbalance
  • Sometimes associated with rapid progression of DR

6

Risk factors -Hypertension

  1. Common in what type of Diabetes?
  2. Range of control?

 

  1. Common in Type II diabetics
  2. Should be carefully controlled< 140/80 mmHg

 

7

Risk factors -Nephropathy

Influence on progession of Diabetes?

 

Nephropathy = kidney disease

Associated with worsening DR

Treating the renal disease can improve DR and allow patient to respond better to treatment of the DR

8

Risk factors -Other ?

Obesity (Especially increased BMI) 

High waist to hip ratio

Hyperlipidaemia

Anaemia

9

DIABETIC RETINOPATHY
Pathogenesis?

Feature of this diseasse? (2)

 

DR is a MICROANGIOPATHY which shows features of microvascular occlusion & leakage.

10

DIABETIC RETINOPATHY

Signs of retinal vascular disease

  1. What can be seen directly
  2. Significance of eye vascular disorder relating to the rest of the body?
  3.  

  1.  Microcirculation 
    Vascular disease which affects the eye can be seen directly
  2. The eye provides clues about pathological vascular changes in the rest of the body

 

11

DIABETIC RETINOPATHY
Signs of retinal vascular disease result from 2 changes to the retinal capillary microcirculation?

  1. Vascular leakage
  2. Vascular occlusion

12

Signs of retinal vascular disease general 

Flow diagram 

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13

DIABETIC RETINOPATHY

Leakage- Haemorrhages

Cause?

  • caused by leakage of blood from damaged vessels
  • dot-blot or flame ( usually inner layer) 

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14

15

Leakage- Oedema of the retina 

Causes?

  • caused by fluid leakage from damaged vessels

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16

Leakage- Exudates
Form by? 

 lipids
lipoprotein
 lipid-containing macrophages

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17

Occlusion- Cotton wool spots

  1. What type of exudate?
  2.  Appearance? Why is it so ?
  3. Location?
  4. Cause?
  5. Factor determine visibility?

  1. Used to be called “soft exudates”
  2. Fluffy, white focal lesions with indistinct margins
    c/b accumulated axoplasmic particles scatter light (normal NF is transparent)
  3. Occur at the margins of an ischaemic retinal infarct
  4. Caused by obstruction of axoplasmic flow & build up of axonal debris in the nerve fibre layer of the retina
  5. Visibility will depend on nerve fibre layer thickness
    Readily seen close to the optic disc where the NFL is thick & less obvious in the periphery where the NFL is thinner

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18

Occlusion

Neovascularisation (new vessels)

  1. Factors?
  2. Consequences on retinal surface and vitreous?
  3. Characteristics of new vessels cf normal ones? Why?

 

  1. Vasogenic factors (VEGF) are released in an ischaemic retina
  2. Causes growth of abnormal vessels & fibrous tissue on to the retinal surface & forwards into the vitreous
  3. The intravitreal vessels are more permeable than normal retinal vessels
    b/c they are located in an abnormal position they break and bleed

 

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19

DIABETIC RETINOPATHY
Pathogenesis ?

  1. What initiate downstream events?
  2. What are downstream events?

 

  1. Hyperglycaemia initiates some downstream vascular events:
  2. Capillaropathy
    When the blood vessel walls degenerate
    Haematological changes
    Deformity of blood cells and thickening of the blood
    Microvascular occlusion
    Irregular blood flow and decreased oxygen

 

 

20

Background DR

Main characteristics?

 

  1. Microaneurisms
  2. Retinal haemorrhages
  3. Macular oedema
  4. Hard exudates

21

  1.  Background DR -microaneurysms
  • ​What is it?
  • Where?
  • What it does to retina? Why ?

  1. Microaneuryms
  • ​Localised outpouching of the capillary wall
  • Often seen in relation to areas of caipllary non-perfusion
  • Microaneurysms can leak plasma into the retina b/c the blood-retinal barrier is broken down or thrombosed

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22

1. Background DR -microaneurysms

  1. Signs? Where in relation to fovea?
  2. Difference to dot haemorrhage?
  3. Sign on FA?

 

 

  1. Tiny red dots, initially temporal to the fovea (earliest signs of DR)
  2. If coated with blood can be hard to tell from dot haemorhhages
  3. On FA: Hyperfluorescent dots

 

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23

2. Background DR –retinal haemorrhages
RNFL haemorrhage​

  1. Where does it arise? Location?
  2. Type of appearance?

 

  1. Arise from larger superficial aretrioles
  2. Flame-like appearance

 

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24

2. Background DR –retinal haemorrhages

Intra-retinal haemorrhage

  1. Arise from?
  2. Location
  3. Appearance?

 

 

  1. Arise from venous end of capillaries
  2. Located in the middle layers of the retina
  3. Red, dot-blot appearance

 

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25

3. Background DR –macular oedema

Show on eye examinations 

  1. Ophthalmoscopy
  2. FFA
  3. OCT

 

  1. Ophthalmoscopy = retinal thickening
  2. FFA = diffuse hyperfluorescence with flower-petal pattern if CMO present
  3. OCT = retinal thickening & cystoid spaces

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26

Background DR –macular oedema

  1. Type of oedema? Cause of each?
  2. Where fluid is found?
  3. If fluid accumulates, what does fovea appear like?

 

 

  1. Caused by
    Diffuseextensive capillary leakage 
    Focal:  leakage from microaneurysms & dilated capillaries
  2. Fluid is found b/w the OPL and INL
    OPL= Outer Plexiform Later (5th)
    INL= Inner Nuclear layer (6th)
  3. cystoid appearance (CMO) -- signifcant vision changes

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27

4. Background DR –hard exudates

  1. Cause?
  2. Location?
  3. Made up of ?
  4. Appearance?
    Margin? Arrangement? Surround by what?

 

  1. Caused by retinal oedema
    Mainly found in the OPL
  2. Develop at the junction of normal & swollen retina
  3. Made up of lipoprotein & lipid filled macrophages
  4. Waxy yellow lesions with distinct margins

    Arranged in clumps/rings

    Often surround microaneurysms

    When leakage stops they absorb over months or years

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28

Diabetic maculopathy

  1. What is it?
  2. What type of Diabetes more likely to develop ?

 

  1. Oedema, hard exudates or ischaemia involving the fovea
  2. Type 2: 
    (Most common cause of vision impairment in diabetics) 

29

Diabetic maculopathy 
Types ? 

 

  1. Focal
  2. Diffuse
  3. Ischaemic
  4. CSMO

 

30

1. Focal maculopathy

Signs on retina ?

FFA sign?
 

  1. Retinal thickening evident with complete or incomplete rings of hard exudates
  2. Focal hyperfluorescence is seen on late FFA due to leakage corresponding to centre of exudate ring 

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31

2. Diffuse maculopathy 
Signs? 

Wide-spread thickening.

Can be associated with cystoid changes.

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32

3. Ischaemic maculopathy

Signs on macular?

Relations to DR type?

  1. Variable signs. Macular can look normal.
  2. Prolifrerative DR can also be present.

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33

4. Clinically significant macular oedema (CSMO)

Definition in relation to Macula?

Definition:

Retinal oedema within 500 μm of macula

Hard exudates within 500 μm of macula

Retinal oedema one disc area (1500 μm) or larger, any part of which is within 1 disc diameter of the centre of the macula

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