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opthalmoo final > Retinal Vascular Disease > Flashcards

Retinal Vascular Disease Flashcards

1
Q

the macula is what

A

The macula is the central and thickest part of the retina, temporal to the optic disc.
There is a high concentration of cone photoreceptors
The presence of xanthophyll pigment gives the macula a yellow tinge

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2
Q

the fovea is what

A

The fovea is a small depression in the centre of the macula.
It lies 2 disc diameters temporal to the edge of the optic disc
It can be recognised by a tiny reflection of light from your ophthalmoscope (foveal reflex)

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3
Q

where are the photoreceptors located

A

The outer retina consists of a layer of sensory cells called photoreceptors
These are of two types, rods and cones
The cones are responsible for colour vision and good visual acuity
The rods are responsible for night vision

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4
Q

retinal pigmented epithelium is what

A

The RPE is a pigmented layer just below the photoreceptors
It is responsible for all of the metabolic needs of the photoreceptors

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5
Q

what is the choroid

A

The choroid is a highly pigmented and vascular layer just below the RPE
It provides the nutrition and oxygen needs of the outer retina
It has a very high blood flow

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6
Q

what is the blood retinal barrieer

A

This is analogous to the blood-brain barrier
Tight intercellular junctions in the retinal blood vessels and the RPE stop leakage of blood contents into the retina
Most retinal vascular disease is associated with damage to this barrier

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7
Q

retinal vascular disease is what

A

Systemic arterial hypertension
Diabetic retinopathy

Other types of retinal vascular disease include:
Sickle cell retinopathy
Retinopathy of prematurity

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8
Q

retinal haemorrhages are what

A

Retinal haemorrhages are an important sign of retinal vascular disease
They occur in different layers of the retina and as a consequence have different appearances:
Pre-retinal (also called sub-hyaloid)
Superficial nerve fibre layer (flame)
Intraretinal- dot and blot
Subretinal

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9
Q

what is a pre-retinal haemhorrhage

A

They lie between the retina and the vitreous gel
They settle to form a horizontal level
They are found in proliferative diabetic retinopathy, subarachnoid haemorrhage and valsalva haemorrhages

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10
Q

what are flame haemhorrhages

A

they look like tye dye

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11
Q

what are dot and blot haemhorrhages

A

These haemorrhages lie deeper in the retina
Blot haemorrhages are a sign of retinal ischaemia
They are found in diabetic retinopathy

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12
Q

what are subretinal haemorrhages

A

These lie under the retina and cause a small retinal detachment and are often circular
They originate from the choroidal blood vessels
They are found in macular degeneration

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13
Q

what is systemic hypertension

A

The severity of retinopathy depends upon the height of the blood pressure, the speed of onset and the duration.
The features of hypertensive retinopathy are caused by damage to the blood-retinal barrier, leading to leakage from retinal capillaries, and thickening of blood vessel walls.

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14
Q

how is hypertensive retinopathy classfied

A

Modified Scheie classification
Grade 0 no changes
Grade 1 barely detectable arterial narrowing
Grade 2 arterial narrowing with focal irregularities
Grade 3 grade 2 plus haemorrhages +/- exudates +/- cotton wool spots
Grade 4 grade 3 plus disc swelling (malignant hypertension)

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15
Q

what are common findings in hypertnesive retinopthay

A

Common findings in chronic elevated BP:
Focal or generalised narrowing of arterioles
Intra-retinal haemorrhages
Branch retinal artery occlusions
Central retinal vein occlusions
Branch retinal vein occlusions
Retinal macroaneurysms

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16
Q

how can systemic hypertension affect the choroidal blood vessels

A

Systemic hypertension can also affect
the choroidal blood vessels. Particularly
in eclampsia and other causes
of accelerated BP
Signs are:
Elschnig spots (pale spots with pigment)
Siegrist streaks

17
Q

what are elschnig posing spots

A

small chorioidal infarcts

18
Q

what factors dtermine if someone with diabetes will develop retinopathy

A

There are several factors which determine whether a patient with diabetes will develop retinopathy:
Duration
After 20 years 99% of IDDM and 60% NIDDM will have retinopathy
Control of glycaemia (Hb A1c levels)
Other factors: blood viscosity, elevated lipids
Systemic hypertension
Carotid stenosis
Pregnancy
Renal disease and anaemia

19
Q

how is diabbtetic retinopathy classified

A

Classification of DR
Background (BDR)
Mild, moderate, severe, very severe BDR
Diabetic macular oedema (clinically significant macular oedema-CSMO)
Proliferative DR (PDR)
Early, high risk, advanced PDR

20
Q

features of diabetic retinopathy (intraretinal changes)

A

Intra-retinal changes
Microaneurysms (indistinguishable from dot haemorrhages with the ophthalmoscope)
Dot and blot intra-retinal haemorrhages
Retinal oedema
(hard) Exudates
Dilatation and beading of retinal veins
Intra-retinal microvascular abnormalities-IRMA

21
Q

what is bdr and what features would you see on a fundus image

A

Background diabetic retinopathy (BDR) refers to the early stage of diabetic retinopathy, which is a complication of diabetes affecting the eyes. In BDR, there are mild changes in the blood vessels of the retina due to prolonged high blood sugar levels.

  • exudates (yellow spots)

venous loop (red loop)

blot hamehorrhage /micranyerusms = red dots

22
Q

what are features of BDR

A

Nerve fibre layer infarcts or cotton wool spots CWS (sometimes called soft exudates)
Arteriolar abnormalities
Focal areas of capillary non-perfusion

23
Q

what is loss of vision in BDR due to

A

Loss of vision in BDR is due to macular oedema (CSMO)
Signs of CSMO are:
Retinal thickening
Exudates approaching fovea
Focal oedema-exudates, microaneurysms
Diffuse oedema

24
Q

What features would you see on a funuds in macular odema

A

exudates

fovea

macula

widespread exudates

severe macular odema

optic disc

25
Q

what are signs that background diapetic retinopthay is progression to proliferative DR

A

Diffuse intra-retinal haemorrhages and microaneurysms in 4 quadrants
Venous beading in 2 quadrants
IRMA in 1 quadrant

Very severe BDR (defined as any 2 of the above) has 45% chance of progressing to of PDR in one year

26
Q

what is pre-proliferative dr

A

Pre-proliferative DR is indicated by:
Severe or very severe BDR plus CWS
CWS indicate poor perfusion and ischaemia
Indicates that other clinical signs of progression should be looked for
Patient is at high risk of developing PDR and should be reviewed more frequently or offered laser treatment

27
Q

what is proliferative DR charcaterised by

A

Characterised by:
Pre-retinal fibrovascular proliferation
Begins with:
Fine new vessels (NV) with little fibrous tissue
These increase in size and develop fibrosis
Later regression of NV with fibrosis along back surface of the vitreous

28
Q

what is PDR

A

problems are caused by traction of virteous on fibrovascular complexes

this leads to pre-retinal hamehorrhage

virteous haemhorhage (sudden loss of vision)

retinal dettachemnt

iris and angle NV causes secondary reubotic glaucoma (very high ipo pressure)

29
Q

what is dr treated by

A

laser

Oedema is caused by leaking vessels
Laser destroys the leaking vessels
We use small numbers of laser applications using green light argon laser
Treatment is directed at leaking microaneurysms in the centre of a ring of exudates
50 micron size, 0.1 second duration

30
Q

how is dr screened for

A

If onset of diabetes is <30 years of age, examine retina within 5 years of diagnosis and review annually
If onset of diabetes is >30 years of age, examine retina at diagnosis and then annually
During pregnancy, the retina should be examined once during every trimester

31
Q

what is the role of anti- VEGF injections

A

Important part of the treatment for macular edema esp if not responding to laser

Laser still the mainstay for proliferative stage

32
Q

how are patients reviewd during screening for DR

A

If no retinopathy or minimal BDR review in 12 months
If mild BDR review in 9 months
If moderate BDR review in 6 months
If severe BDR review in 4 months
If macular oedema refer for laser
If PDR refer for laser

opthalmoo final (13 decks)

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