Diabetic Eye Disease: Clinical Features and Classification Flashcards
state the four types of diabetes
-type 1
-type 2
-maturity onset diabetes of the young (MODY)
-gestational diabetes
what type of diabetes is MODY similar to?
type 2- although NOT linked to obesity- occurs before 25 yo and required insulin injections
what is type 1 diabetes mellitus?
-body unable to produce insulin
-more common in childhood
- genetic risk prevalence
what is risk (%) to child if mother has DM?
2%
what type of cells are destroyed in type 1 DM?
pancreatic beta cells
what is risk (%) to child if father has DM?
8%
what is Type 2 DM?
Insulin resistance OR bodys inability to produce enough insulin
how can DM T2 be controlled?
-diet
-excercise
-tablets
-insulin
what are risk factors of Type 2 DM?
-Age
-smoking
-obesity
-lack of physical activity
can race be a risk factor of Type 2 DM?
yes
around ~6x in South Asian & ~3x in Afro-Caribbean people compared to Caucasian.
risk if 1 PARENT has T2 DM?
Risk ~15% if 1 parent has type II
does risk of T2 DM increase if both parents have it?
yes ~75% if both have.
list the 7 eye conditions associated with diabetes
-rubeoses iridis
-cataract-PSC
-OM-diplopia- can be underlying cause of 3rd, 4th or 6th nerve palsies
-corneal erosions- ulcers ,persistent epithelial defets
-diab retinopathy
-AION
-CRVO/CRAO
What are the two types of diabetic eye disease and where do they occur on the fundus?
can be diabetic retinopathy (peripheral) or maculopathy (macula)
the presence of what molecule in the blood gives an indication of how well controlled diabetes is?
HbA1C- higher levels mean diabetes is less well controlled
what other vascular condition can also be a risk factor for DR?
hypertension
name two sight threatening forms of DR?
-Proliferative DR
-Macula oedema
What is non-proleferative DR
no formation of new blood vessels
what is proliferative DR?
Formation of new blood vessels
list 5 signs of DR that can cause sight loss
-macula oedema and exudates
-macular ischaemia
-fibrous tissue formation= new bvs
–vitreous haemorrhages as result of new bvs
-ret detachment
how are exudates formed in DR?
due to leakage of fluid and lipoproteins from bvs
what 5 factors affect the risk of getting DR and the risk of its progression?
- how long px has had DM- longer means higher risk
- Control of DM-poor control= high risk
- Type of diab-type 1 has higher risk
- HTN
- high cholesterol- covered in another flashcard
why does having high levels of cholesterol link to risk of DR?
as this can cause exudates
what is the screening programme for DR called?
NHS diab eye screening programme
how old should a diabetic patient be to be registered on the NHS diab screening programme?
12 years old
is DR graded based off the appearance of the fundus or vision?
appearance of fundus
what are the 4 grading classifications of DR and what are they called and how do we refer them?
-R0- no retinopathy present
-R1-background DR (no referral required)
-R2- pre prolif - refer to Ophthalmology
-R3-proliferative retinopathy (urgent referral)
what are the features of R1 DR?
-Microaneurysms
-ret haemmorhages - not within definition of R2
-exudates- in absence of r2 feautures
-venous loops- in absence of R2 features
-cotton wool spots- in presence of other R1 Features
What are features of R2 DR?
-multiple blot haem
-venous beading
-venous reduplication (?)
-Intra-retinal microvascular abnormality (IRMA)
What are feautures of R3 DR?
- NVD- new vessels on disc
-NVE- new vessels elsewhere
-pre-retinal/vitreous haem
-pre retinal fibrosis and tractional ret detachment
would a single Cotton wool spot be a feature of DR?
No- it would be classed as no retinopathy R0
Would other eye conditions such as CRVO be a feature of DR?
No- would be classed as no retinopath R0
Would a single microaneurysm be a feature of DR?
YES- characteristic of R1 DR
What are microanuerysms described as, their size and where are they usually found?
dark red spots, sharp border, < 125μm in diameter,
-usually temporal to macula
where are microaneurysms located in the retina?
found in inner nuclear layer
where are dot haemmorhages found in the retina?
inner plexiform layer
are dot haemmorhages larger or smaller than microaneurysms ?
larger
are dot haemmorhages larger or smaller than blot haemorrhages?
smaller
are microaneurysms easy to differentiate from dot haem?
not using ophthalmoscpy or fundus - easier with oct?
where are blot haem located?
deeper between IPL and INL
what can the appearance of blot haem be an indication of?
local ischaemia
are blot haem a feature of R1 or R2?
BOTH- if only a few R1 if multiple (8-10) can be R2
Where are flame shaped haem found?
in nerve fibre layer
why are flame shaped haem flame shaped?
as they follow the path of the retinal nerve fibres
what 3 other eye conditions are flame shaped haem found in?
-systemic HT
-glauc
-vein occlusion
where do the exudates leak out from?
capillaries in the outer plexiform and inner plexiform layer usualy oedema
what is oedema and how does it present on the fundus ?
accumulation of fluid in the retina- can appear as cysts or greyish
how is oedema best detected?
oct
what are cotton wool spot and where are they found
fluffy white lesions found in RNFL
why do cotton wool spots occur?
focal or diffuse inner retinal ischaemia disrupting RNFL axonal transport
are cotton wool spots commonly found in the thickets or thinnest part of retina?
thickest- eg posterior pole
is venous looping a feature of R2?
NO- has recently been moved to R1- but do check for other identifiable R2 features as then would be classed as R2
what does Acronym HOME stand for in R1 DR?
Haemmorhages
Oedema
Microaneurysms
Exudates
what are the 3 distinct feautures of R2?
-IRMA
-multiple blot haem
-venous beading
do we refer pxs with suspect R2 DR?
yes
what is IRMA an indication of?
Retinal ischaemia
what is IRMA
Dilated capillaries that ‘mimic’ new bvs- IRMA vessels DON’T leak
do IRMA vessles cross over major vessels?
NO- cross over each other
what is another possible mechanism for formation of IRMA?
variant of colalteral formation - can be seen with localised arteriolar occlusion and cotton wool spots
MOST RELIABLE SIGN OF SEVERE ISCHAEMIA?
venous changes
what are some (4) features of venous changes?
segmented, beading and dilated vessels- can have vessel occlusion also, variable calibre
What are the 4 main fratures of R3- Prolif Retinopathy?
New vessels on disc (NVD)
New vessels elsewhere (NVE)
Pre-retinal or vitreous haemorrhages
Pre-retinal fibrosis ± tractional retinal detachment
what does fibrosis look like on a fundus?
appears white sort of like myelination
what stimulates the activation of growth of new vessels
VEGF
Why is the growth of new vessels an important indication in R3?
new vessels (growth looks blossom like on fundus) tend to be very fragile and can leak and bleed as they grow ON and not IN retina.
-Can also loop back on themselves and widen in diameter
do new vessels cross over major arteries and veins?
YES- differentiation between these and IRMA (which don’t)
name another differentiation of new vessles vs IRMA
Obscure underlying lesions therefore on top of retina, not within it (unlike IRMA)
What can be the result when new vessels eventually grow in vitreous and why might this require an urgent referral?
vitreous haemmorhages THAT CAN CAUSE TRACTION (PULLING) and eventually result in ret detachment
as R3 DR has inner retinal growth of new vessles, which other main eye condition has CHOROIDAL neovasc?
Wet AMD
how do we characterise Neovasc at the Disc?
new vessels on or within 1DD from the optic nerve head
what is the percentage risk of sight loss if NVD is left untreated for 5 years?
50 %
what can also be accompanied with NVD?
Neovasc elsewhere on fundus (NVE)
How can we differentiate between NVE and IRMA?
NVE appears more wispy and is often temporal to macula but can also be nasal
what is the risk of blindess if NVE is left untreated for 5 years?
30%
wat can be a symptom patient may complain of in pre-retinal/vitreous haem?
px may complain of sudden visual loss or sudden onset of dark floaters - can block or obscure our view of retina
does vit haem have a good or poor prognosis?
generally poor- may take months or years to resolve if erythrocytes break into vitreous body. Can lead to risk of 30% blindness if left untreated
what surgery can be done f itr haem unresolved for longer than 6 months?
Vitrectomy carried out if unresolved in 6 months. - t o compeltely remove vitreous
what else can cause the vitreous haemmorhages?
age- vitreous shrinking leading them to rupture easily
why do Pre-retinal haemorrhages have a flat top?
NB not all of them have a flat top
because the red cells settle down due to gravity- if px sits upright?
how can vit haem lead to a ret detachment?
Contraction of fibrous tissue can pull retina to cause tractional retinal detachment (TRD).
what surgery can be done to prevent tractional retinal detachment?
vitrectomy
how does the retina look during tractional ret detachment?
The retina may appear wrinkled (traction lines) or thrown into bumps and folds, sometimes with a visible tear. : because the fibrous tissue contracts and pulls on the retina
what is rubeoses irides and when can this occur?
occurs in prolif DR- new vessel growth on iris or ange in severe ret hypoxia
can rubeoses irides result in glauc and if so, why?
Can lead to neovascular glaucoma due to fibrovascular tissue blocking angle of drainage. - hence increase in iops
signs and symptoms of rubeosis irdes?
Vessels and diffuse reddening of the iris may be seen. Patients may complain that the eye is often extremely painful
what is R3S?
Stable diabetic proliferative retinopathy- evidence of peripheral retinal laser treatment AS WELL AS a fundus photo showing a stable retina at or after a short period of time after the one taken in HES- basically compare the 2 pics
what is the DESP classification of Maculopathy?
M0-no maculopathy
M1-maculopathy (requires referral)
do we classify maculopathy based off appearance of fundus and vision?
both
what are features of M0?
Non-referable maculopathy (MAs or haems within 1DD of fovea but vision better than 0.3 LogMAR/ Snellen 6/12)
WHAT ARE FEATURES OF M1?
- 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 0.3 logMAR
do we treat maculopathy?
yes, if there’s Clinically Significant Macular Oedema (CSMO)
what category of maculopathy do exudates or haemorrhages within 1DD (and vision <6/12) fall into?
M1- referable Maculopathy
do we find exudates in M1?
YES- can have group of exudates larger than ½ disc area in macula
- can be associated with oedema
-May find accompanying aneurysms (source of leak)
what happens to the retina in macular oedema?
it thickens
what is the P classification in DR?
Photocoagulation scars- can be P0 or P1
What is P0?
no photocoagulation (laser scars)
what is P1?
Presence of photocoagulation scars:
Evidence of focal/ grid laser to macula
Evidence of peripheral scatter laser
HOW DE WE MANAGE R1?
Annual review by Optometrist / screening service
how do we manage R2 OR M1?
Refer to HES
To be seen soon (within 4 weeks)
How do we manage a px with jnew vessel formation?
Refer to HES
To be seen urgently (within 1 week)
how do we manage a px with:
Sudden loss of vision
Evidence of retinal detachment
Pre-retinal/ vitreous haemorrhage
Rubeosis iridis
EMERGENCY- refer to HES
How do we manage P1?
Post treatment: annual review
Refer to HES: if not recorded before
TRUE OR FALSE-if have M1 then automatically have R1
True- as features seen in M1 are in classification of R1 (provided vidion worse than 6/12)
TRUE OR FALSE-if have M1 then automatically have R1
True- as features seen in M1 are in classification of R1 (provided vidion worse than 6/12)
what is this ?
NVD
what is this?
NVE
what is this?
pre-retinal haem
what is this?
vitreous haem
what is this?
IRMA
grade this
R2 - multiple blot haem in all 4 quads
what is this and what grade is it?
looping - R1
grade this
R1M1
