Diabetic eye disease: clinical features and classification

Question 1

what causes T1 DM

Answer 1

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

Question 2

what causes T2 DM and how is it controlled

Answer 2

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

Controlled with diet, exercise, tablets, insulin

Question 3

what lifestyle factors is T2 DM strongly associated with

what are the 2 non-modifiable risk factors

Answer 3

Strongly associated with:
obesity
lack of physical activity
smoking

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

• Risk increases with age

Question 4

what type of disease is diabetic retinopathy (DR)

what is it the leading cause of

Answer 4

Microvascular + neurodegenerative retinal disease

Leading cause of blindness in working population

Question 5

what 2 locations of DR can there be

Answer 5

peripheral (R)
or
macular (M)

Question 6

what are the 2 sight-threatening forms of DR

Answer 6

proliferative DR and macular oedema

Question 7

what 2 things can DR be

Answer 7

non proliferative no new blood vessels

proliferative new blood vessels
= higher risk of sight loss

Question 8

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

Answer 8

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)

Hypertension

Question 9

what is the main classification system used

how is it used

Answer 9

NHS Diabetic Eye Screening Programme (DESP)

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

Question 10

who should be registered on the NHS screening programme

Answer 10

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

Question 11

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

Answer 11

Microaneurysm(s)
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

Question 12

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

Answer 12

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

Question 13

which vessels are micro aneurysms of

Answer 13

of the capillaries - small vessels

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

Question 14

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

Answer 14

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

Question 15

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

Answer 15

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

Question 16

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

Answer 16

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)

Question 17

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

Answer 17

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

Question 18

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

Answer 18

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

Question 19

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

Answer 19

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)

Question 20

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

Answer 20

cotton wool spots obscure the blood vessels underneath = at RNFL

exudates are deeper within the retina

Question 21

what is a venous loop

what is this a sign of

Answer 21

Abrupt curving away from normal path of vessel

Sign of retinal ischaemia

Question 22

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

Answer 22

HOME

Haemorrhage
Oedema
Micro aneurysms
Exudate

Question 23

when do cotton wool spots not count as R1 DR

and when do they count as R1

Answer 23

R1 if present with no other signs

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

Question 24

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

Answer 24

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

Question 25

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

Answer 25

Multiple blot haemorrhages Venous beading Venous reduplication Intra-retinal microvascular abnormality (IRMA) refer to ophthalmologist, soon within a 4 week period

Question 26

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

Answer 26

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

Question 27

what does IRMA (Intraretinal Microvascular Anomaly) indicate

Answer 27

Indicates retinal ischemia

Question 28

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

Answer 28

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

Question 29

what is IRMA (Intraretinal Microvascular Anomaly) not but what do they do in response to ischaemia

Answer 29

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

Question 30

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

Answer 30

they won't cause haemorrhages or leak exudates they are just normal capillaries that have adapted to ischaemia

Question 31

what is the most reliable sign in R2 of ischaemia

Answer 31

venous changes

Question 32

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

Answer 32

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

Question 33

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

Answer 33

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

Question 34

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

Answer 34

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

Question 35

what 6 features describes the new vessels in active proliferative R3a

Answer 35

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

Question 36

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

Answer 36

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

Question 37

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

Answer 37

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

Question 38

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

Answer 38

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

Question 39

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

Answer 39

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

Question 40

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

Answer 40

Px reports sudden visual loss or sudden onset of dark floaters Appears dark, may completely block view of the retina

Question 41

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

Answer 41

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

Question 42

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

Answer 42

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

Question 43

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

Answer 43

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

Question 44

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

Answer 44

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)

Question 45

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

Answer 45

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

Question 46

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

Answer 46

TRD associated with sudden loss vision Vitrectomy carried out to prevent TRD

Question 47

what 2 things can a haemorrhage cause

Answer 47

scar tissue forming or fibrous tissue growing along the new blood vessels

Question 48

what causes Rubeosis Iridis and what may this lead to

Answer 48

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

Question 49

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

Answer 49

refer them asap as an ocular emergency

Question 50

what 2 things is R3s DR

Answer 50

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

Question 51

what is the DESP classifications of maculophathy in DR

Answer 51

M0 | M1

Question 52

what are the 2 features of M0

Answer 52

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

Question 53

what is classed as a non referable maculopathy

Answer 53

M0 MAs or haems within 1DD and vision better than 0.3 LogMAR/ Snellen 6/12

Question 54

list 4 clinical features of M1 and what does this require

Answer 54

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

Question 55

what does the DESP define as the macular region

Answer 55

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

Question 56

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

Answer 56

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

Question 57

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

Answer 57

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

Question 58

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

Answer 58

has to be stretched over the 1DD

Question 59

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

Answer 59

often 'cystoid' in nature

Question 60

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

Answer 60

ONLY if associated with VA worse than Snellen 6/12

Question 61

what is the DESP classifications of Photocoagulation Scars

Answer 61

P0 | P1

Question 62

what feature does P0 have

Answer 62

No photocoagulation (laser scars)

Question 63

what 2 features does P1 have

Answer 63

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

Question 64

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

Answer 64

R2 (pre-proliferative changes) Unexplained retinal findings M1 (referable maculopathy) Unexplained drop in VA

Question 65

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

Answer 65

New vessels formation

Question 66

when will you Refer your px to HES -To be seen as an emergency list 4 reasons

Answer 66

Sudden loss of vision Evidence of retinal detachment Pre-retinal/vitreous haemorrhage Rubeosis iridis

Question 67

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

Answer 67

Post treatment: annual review Refer to HES: if not recorded before