Diabetic Retinopathy 1 Flashcards
DIABETIC RETINOPATHY
More common in what type of Diabetes ?
Type I diabetics
DIABETIC RETINOPATHY
Risk factors?
- Duration of diabetes
- Poor metabolic control
- Pregnancy
- Hypertension
- Nephropathy
- Other things
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
Risk factors –Poor control
( Not as important as duration but still relevant)
- Benefit of good BSL control?
- Which type of Diabetes benefits more?
- What increase risk of proliferative DR?
-
Good BSL control ⇒ prevent/delay development/progression of DR
Problem: it is associated with increased risk of hypos - Type I diabetics
- Raised HbA1c (glycated haemoglobin) = increased risk of proliferative DR
Risk factors –Pregnancy
Factors inflencing DR?
( may associate with Rapid progression of 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
Risk factors -Hypertension
- Common in what type of Diabetes?
- Range of control?
- Common in Type II diabetics
- Should be carefully controlled< 140/80 mmHg
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
Risk factors -Other ?
Obesity (Especially increased BMI)
High waist to hip ratio
Hyperlipidaemia
Anaemia
DIABETIC RETINOPATHY
Pathogenesis?
Feature of this diseasse? (2)
DR is a MICROANGIOPATHY which shows features of microvascular occlusion & leakage.
DIABETIC RETINOPATHY
Signs of retinal vascular disease
- What can be seen directly
- Significance of eye vascular disorder relating to the rest of the body?
3.
-
Microcirculation
Vascular disease which affects the eye can be seen directly - The eye provides clues about pathological vascular changes in the rest of the body
DIABETIC RETINOPATHY
Signs of retinal vascular disease result from 2 changes to the retinal capillary microcirculation?
- Vascular leakage
- Vascular occlusion
Signs of retinal vascular disease general
Flow diagram

DIABETIC RETINOPATHY
Leakage- Haemorrhages
Cause?
- caused by leakage of blood from damaged vessels
- dot-blot or flame ( usually inner layer)

Leakage- Oedema of the retina
Causes?
- caused by fluid leakage from damaged vessels

Leakage- Exudates
Form by?
lipids
lipoprotein
lipid-containing macrophages

Occlusion- Cotton wool spots
- What type of exudate?
- Appearance? Why is it so ?
- Location?
- Cause?
- Factor determine visibility?
- Used to be called “soft exudates”
-
Fluffy, white focal lesions with indistinct margins
c/b accumulated axoplasmic particles scatter light (normal NF is transparent) - Occur at the margins of an ischaemic retinal infarct
- Caused by obstruction of axoplasmic flow & build up of axonal debris in the nerve fibre layer of the retina
- 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

Occlusion
Neovascularisation (new vessels)
- Factors?
- Consequences on retinal surface and vitreous?
- Characteristics of new vessels cf normal ones? Why?
- Vasogenic factors (VEGF) are released in an ischaemic retina
- Causes growth of abnormal vessels & fibrous tissue on to the retinal surface & forwards into the vitreous
- The intravitreal vessels are more permeable than normal retinal vessels
b/c they are located in an abnormal position they break and bleed

DIABETIC RETINOPATHY
Pathogenesis ?
- What initiate downstream events?
- What are downstream events?
- Hyperglycaemia initiates some downstream vascular events:
-
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
Background DR
Main characteristics?
- Microaneurisms
- Retinal haemorrhages
- Macular oedema
- Hard exudates
- Background DR -microaneurysms
- What is it?
- Where?
- What it does to retina? Why ?
- 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

1. Background DR -microaneurysms
- Signs? Where in relation to fovea?
- Difference to dot haemorrhage?
- Sign on FA?
- Tiny red dots, initially temporal to the fovea (earliest signs of DR)
- If coated with blood can be hard to tell from dot haemorhhages
- On FA: Hyperfluorescent dots

2. Background DR –retinal haemorrhages
RNFL haemorrhage
- Where does it arise? Location?
- Type of appearance?
- Arise from larger superficial aretrioles
- Flame-like appearance

- Background DR –retinal haemorrhages
Intra-retinal haemorrhage
- Arise from?
- Location
- Appearance?
- Arise from venous end of capillaries
- Located in the middle layers of the retina
- Red, dot-blot appearance

- Background DR –macular oedema
Show on eye examinations
- Ophthalmoscopy
- FFA
- OCT
- Ophthalmoscopy = retinal thickening
- FFA = diffuse hyperfluorescence with flower-petal pattern if CMO present
- OCT = retinal thickening & cystoid spaces

Background DR –macular oedema
- Type of oedema? Cause of each?
- Where fluid is found?
- If fluid accumulates, what does fovea appear like?
- Caused by
Diffuse: extensive capillary leakage
Focal:leakage from microaneurysms & dilated capillaries - Fluid is found b/w the OPL and INL
OPL= Outer Plexiform Later (5th)
INL= Inner Nuclear layer (6th) - cystoid appearance (CMO) – signifcant vision changes

- Background DR –hard exudates
- Cause?
- Location?
- Made up of ?
- Appearance?
Margin? Arrangement? Surround by what?
- Caused by retinal oedema
Mainly found in the OPL - Develop at the junction of normal & swollen retina
- Made up of lipoprotein & lipid filled macrophages
- Waxy yellow lesions with distinct margins
Arranged in clumps/rings
Often surround microaneurysms
When leakage stops they absorb over months or years

Diabetic maculopathy
- What is it?
- What type of Diabetes more likely to develop ?
- Oedema, hard exudates or ischaemia involving the fovea
-
Type 2:
(Most common cause of vision impairment in diabetics)
Diabetic maculopathy
Types ?
- Focal
- Diffuse
- Ischaemic
- CSMO
- Focal maculopathy
Signs on retina ?
FFA sign?
- Retinal thickening evident with complete or incomplete rings of hard exudates
- Focal hyperfluorescence is seen on late FFA due to leakage corresponding to centre of exudate ring

2. Diffuse maculopathy
Signs?
Wide-spread thickening.
Can be associated with cystoid changes.

- Ischaemic maculopathy
Signs on macular?
Relations to DR type?
- Variable signs. Macular can look normal.
- Prolifrerative DR can also be present.

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
