Diabetic eye disease: clinical features and classification Flashcards Preview

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Flashcards in Diabetic eye disease: clinical features and classification Deck (67)
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what causes T1 DM

Body loses ability to produce insulin (not a lifestyle type)


what causes T2 DM and how is it controlled

Ineffective use of insulin (insulin resistance), or insufficient insulin production

Controlled with diet, exercise, tablets, insulin


what lifestyle factors is T2 DM strongly associated with
what are the 2 non-modifiable risk factors

Strongly associated with:
lack of physical activity

Non modifiable risk factors:
- Race: Prevalence increased ~6x in South Asian and ~3x in Afro-Caribbean people compared to Caucasian

- Risk increases with age


what type of disease is diabetic retinopathy (DR)
what is it the leading cause of

Microvascular + neurodegenerative retinal disease

Leading cause of blindness in working population


what 2 locations of DR can there be

peripheral (R)
macular (M)


what are the 2 sight-threatening forms of DR

proliferative DR and macular oedema


what 2 things can DR be

non proliferative no new blood vessels

proliferative new blood vessels
= higher risk of sight loss


what 4 things is the risk of DR (and risk of progression) related to

Duration DM - longer more likely to get

Control of DM (Higher HbA1c [glycated haemoglobin] indicates poor control)

Type of diabetes (77% type I vs 25% type II)



what is the main classification system used
how is it used

NHS Diabetic Eye Screening Programme (DESP)

Each eye is given an R (peripheral retinopathy) and M (maculopathy) grade


who should be registered on the NHS screening programme

Everyone with diabetes aged over 12 years

if you see a px above 12 y/o with DM and is not on the scheme, you need to refer then to their GP to get registered


what are the 5 fundus signs of R1 classification of peripheral DR
and what is required to do if you see this

Retinal haemorrhage(s) not within definition of R2
Exudate (in absence of referable R2 features)
Venous loop(s) (in absence of referable R2 features)
Cotton wool spots in presence of other R1 features

Background DR
referral not required - as don't need treatment


what does a single microaneurysm diagnose
what is their appearance and what size
what are they smaller than
where abouts are they usually located
which layer of the retina are they in

Single microaneurysm diagnoses DR
Dark red dots, sharp border, less than 125μm in diameter
Smaller than vein diameter at ONH
Usually temporal to macula
Inner nuclear layer


which vessels are micro aneurysms of

of the capillaries - small vessels

aneurysm = weakness of a BV wall which causes the BV wall to balloon out


what causes dot haemorrhages
what are they larger than and what are they smaller than
what are they not different to in appearance when using ophthalmoscopy/fundus photography

Capillaries in inner plexiform layer are ruptured
Larger than microaneurysms but smaller than blot haemorrhages
Not reliably differentiated from micro aneurysms based on using ophthalmoscopy / fundus photography


where are blot haemorrhages found in the retinal layers
what is their appearance
what are these a sign of
how many of these are classed as severe, as R1 and as R2

Deeper haemorrhages of capillaries between IPL and INL
Larger, darker than dot haemorrhage
Often sign of local ischaemia especially if temporal
more than 20 = severe. If only a few = R1, if many = R2


where in the retinal layer are flame shaped haemorrhages found
what are they often seen with
which 3 other eye diseases are they seen in

Superficial within nerve fibre layer = more feathery appearance
Often with cotton wool spots
Also seen in systemic hypertension, glaucoma, vein occlusion (so can't immediately say flame haemorrhage is DR)


what are exudates
which retinal layer are they found
what will px's with this also have
what can happen to them

Lipid and lipoprotein leaked from capillaries
in OPL or IPL
= seen as hard exudates - are yellow/white deposits
px will also have oedema with this
Can reabsorb spontaneously/post laser treatment


what is oedema
how can you not see oedema in clinic and how can you see it
what signs may you see in association with haemorrhages and micro aneurysms
what sign is the best guide to oedema

Accumulation of fluid within retina
can't see if no stereo e.g. monocular view so OCT views is better to see
May see cysts and greying in association with haemorrhages and microaneurysms
Best guide to oedema is presence of exudate


what is the appearance of cotton wool spots like and which layer of the retina are they found
what is CWS caused by
what can happen to them

Fluffy white lesions in RNFL (Often found where the RNFL is thickest i.e. posterior pole)

Caused by focal or diffuse inner retinal ischaemia, disrupting RNFL axonal transport

Reabsorb but can take 6+ months (if theres recovery from the ischamia)


how can you see that cotton wool spots are at the top layers of the retina
and other what R1 sign is found in the deeper layers within the retina

cotton wool spots obscure the blood vessels underneath = at RNFL

exudates are deeper within the retina


what is a venous loop
what is this a sign of

Abrupt curving away from normal path of vessel

Sign of retinal ischaemia


what abbreviation best describes/sums up the features of R1 Background DR and what does it stand for


Micro aneurysms


when do cotton wool spots not count as R1 DR
and when do they count as R1

R1 if present with no other signs

but if present with haemorrhages / exudates, form a part of R1


what should you do if you see a patient with background R1 DR features

refer them to the GP for diabetic screening programme if they don't currently get it done
but they're not going to be treated


what are the 4 fundus signs of pre-proliferative R2 DR and what do you need to do if you see this

Multiple blot haemorrhages
Venous beading
Venous reduplication
Intra-retinal microvascular abnormality (IRMA)

refer to ophthalmologist, soon within a 4 week period


what are the appearance of blot haemorrhages in R2 and how does this compare to R1

R2 - multiple blot haemorrhages
R1 - 1/2 blot haemorrhages


what does IRMA (Intraretinal Microvascular Anomaly) indicate

Indicates retinal ischemia


what are the 4 features in the appearance of IRMA (Intraretinal Microvascular Anomaly) like

Mimic new vessels but are thought to represent dilated capillaries in area of occlusion

Variable calibre (thickness), odd branching patterns and sharp angles
Appear to run from arterioles to venules

No crossing of major vessels

Don’t leak


what is IRMA (Intraretinal Microvascular Anomaly) not

but what do they do in response to ischaemia

They're not new blood vessels

But because of ischaemia, they dilate and try to bring more blood into the area (i.e. they just adapt) as a response


how is IRMA (Intraretinal Microvascular Anomaly) different from new blood vessels

they won't cause haemorrhages or leak exudates

they are just normal capillaries that have adapted to ischaemia


what is the most reliable sign in R2 of ischaemia

venous changes


what are the 3 main appearances that describes venous changes as found in R2

Veins variable calibre (changes in thickness along its length)
Segmented, beaded, dilated
Beading = localised areas increased calibre
Occluded vessels


what are the 4 fundus signs of R3 proliferative retinopathy and what will you do if you see this

New vessels on disc (NVD)
New vessels elsewhere (NVE)
Pre-retinal or vitreous haemorrhages
Pre-retinal fibrosis ± tractional retinal detachment

will refer px urgently - px is at risk of sight loss quite soon


what causes the new vessel growth in Active Proliferative (R3a) DR

caused by endothelial cell proliferation in response to up regulation of growth factors produced by RPE in ischaemic retina (response to hypoxia)

The thought is that the retina is experiencing areas of hypoxia, or is "under-nourished". In an effort to compensate for this problem, the eye grows new vessels in the areas lacking circulation


what 6 features describes the new vessels in active proliferative R3a

New vessels are very fragile, and tend to leak and bleed (so aren't very affective)

Often loop back on themselves and widen in diameter
Will cross major vessels (unlike IRMA)

Often form ‘blossom’ of numerous vessels in a patch together - new BV's bending back on themselves

Obscure underlying lesions therefore on top of retina, not within it (unlike IRMA) as they grow on top of the retina rather than in it

Eventually grow into vitreous


what is there a high risk of in Active Proliferative (R3a) and what is this associated with
when this is seen what action is required

High risk of vitreous haemorrhage
Associated with fibrous traction on retina
Requires urgent referral


where about do new vessels at the disc appear on the retina in Active Proliferative (R3a) DR
when is it usually a R2 feature
what risk is there if the NVD is untreated

New vessels on or within 1 DD from ONH
Rest of retina = usually R2 features
50% risk blindness in 5y if untreated


where do new vessels elsewhere appear in Active Proliferative (R3a)
what is there appearance like
what are they commonly associated with
what risk is there if the NVE is untreated and what is it's prognosis slightly better than

New vessels more than 1 DD from ONH
Often temporal to macula, sometimes nasally

Fine friable vessels usually arising from large veins

Commonly associated with R2 venous changes

30% risk blindness in 5 years if left untreated
prognosis slightly better than NVD


if a pre-retinal/vitreous haemorrhage as seen in Active Proliferative (R3a) DR is seen:
what must you assume
when does this occur

If present, assume new vessels

Occur when new vessels grow forward from retina, cross the subhyaloid / preretinal space, and enter the vitreous


what will a patient who has a pre-retinal/vitreous haemorrhage as seen in Active Proliferative (R3a) DR, what symptoms will they report

how will it appear when you view it

Px reports sudden visual loss or sudden onset of dark floaters

Appears dark, may completely block view of the retina


in what case will a pre-retinal/vitreous haemorrhage as seen in Active Proliferative (R3a) DR take a long time to clear
what is the risk of this pre-retinal/vitreous haemorrhage if it is left untreated

Takes long time to clear if erythrocytes break into vitreous body (months/years)

Untreated, 30 % of eyes will be blind within 1 year of first vitreous haemorrhage


what causes the vessels in pre-retinal/vitreous haemorrhage as seen in Active Proliferative (R3a) DR to rupture

These vessels rupture easily, associated fibrous tissue contracts and tears them, as does the normal shrinkage of the vitreous with age


what is the difference in appearance of a pre-retinal haemorrhage and a vitreous haemorrhage and why

pre-retinal haemorrhage often has a flat top due to red blood cells settling down due to gravity when a px is sit upright

vitreous haemorrhage does NOT have a flat top appearance - it looks more disorganised


what is fibrous tissue associated with/caused by
what can the contraction of this fibrous tissue cause

Fibrous tissue associated with new blood vessels and with previous vitreous / pre-retinal haemorrhage

Contraction of fibrous tissue can pull retina to cause tractional retinal detachment (TRD)


when may fibrous tissue be visible
how may the retina appear as a result of this fibrous tissue

Pale fibrous tissue may be visible

Retina may appear wrinkled (traction lines), bumped and folded, or tears may be visible


what symptom is the tractional retinal detachment caused by due to the contraction of the fibrous tissue
what procedure is carried out to prevent the occurrence of a TRD

TRD associated with sudden loss vision

Vitrectomy carried out to prevent TRD


what 2 things can a haemorrhage cause

scar tissue forming
fibrous tissue growing along the new blood vessels


what causes Rubeosis Iridis and what may this lead to

Severe retinal hypoxia (widespread proliferative DR) may lead to growth factors producing new vessel growth on iris or in angle

Can lead to neovascular glaucoma due to fibrovascular tissue blocking angle of drainage = dramatic sudden increase in pressure - the eye is often extremely painful


what must you do if you see Rubeosis Iridis in your px

refer them asap as an ocular emergency


what 2 things is R3s DR

Stable post treatment

Evidence of Peripheral Retinal Laser Treatment
Stable retina compared to photograph taken at or shortly after discharge from the Hospital Eye service (HES)


what is the DESP classifications of maculophathy in DR



what are the 2 features of M0

No maculopathy
Non-referable maculopathy (MAs or haems within 1DD and
vision better than 0.3 LogMAR/ Snellen 6/12)


what is classed as a non referable maculopathy


MAs or haems within 1DD and
vision better than 0.3 LogMAR/ Snellen 6/12


list 4 clinical features of M1 and what does this require

Exudate within 1 disc diameter of the centre of the fovea

Circinate or group of exudates within the macula

Retinal thickening within 1 DD of the centre of the fovea

Any microaneurysm or haemorrhage within 1 DD of the centre of the fovea ONLY if associated with VA worse than Snellen 6/12 or 0.5

requires referral - Requires treatment: Clinically Significant Macular Oedema (CSMO)
Needs laser or anti-VEGF treatment


what does the DESP define as the macular region

that part of the retina which lies within a circle centred on the centre of the fovea whose radius is the distance between the centre of the fovea and the temporal margin of the disc
= a large area and not just the foveal region


in M1, what is the Circinate or group of exudates within macula usually associated with and what else may you find with it

Usually associated with oedema
May find accompanying aneurysms (source of leak)


in M1, what is the Retinal thickening within 1 DD of the centre of the fovea:
due to
how can it be easier to spot clinically

Due to macular oedema

Easier to spot using OCT or stereoscopic viewing e.g. volk


in M1, what does the retinal thickening/oedema have to be in order to be immediately referable

has to be stretched over the 1DD


in M1, what type is the retinal oedema seen within 1 DD in nature

often 'cystoid' in nature


when is it only classed as M1 if you see any microaneurysm or haemorrhage within 1 DD of the centre of the fovea

ONLY if associated with VA worse than Snellen 6/12


what is the DESP classifications of Photocoagulation Scars



what feature does P0 have

No photocoagulation (laser scars)


what 2 features does P1 have

Presence of photocoagulation scars:

Evidence of focal/grid laser to macula
Evidence of peripheral scatter laser

seen as white or with a bit of pigmentation


when will you Refer your px to HES - To be seen soon (within 4 weeks)

list 4 reasons

R2 (pre-proliferative changes)

Unexplained retinal findings

M1 (referable maculopathy)

Unexplained drop in VA


when will you Refer your px to HES -To be seen urgently (within 1 week)

New vessels formation


when will you Refer your px to HES -To be seen as an emergency

list 4 reasons

Sudden loss of vision

Evidence of retinal detachment

Pre-retinal/vitreous haemorrhage

Rubeosis iridis


how will you manage a px with P1 and when will you refer them

Post treatment: annual review

Refer to HES: if not recorded before