Retinal Vein Occlusion Flashcards
Arteriolosclerosis
Causative factor for branch retinal vein occlusion
BRVO
Pathogenesis of Retinal Vein Occlusion?
- Causative factor for branch retinal vein occlusion
BRVO = Arteriolosclerosis - Arteriole and its corresponding vein share a common connective sheath
⇒Thickening of arteriole → Compress vein
- Central retinal vein & artery share a common sheath at arteriovenous crossings posterior to lamina cribrosa
- Atherosclerotic changes of the artery may compress vein → Cause Central Retinal Vein Occlusion ( CRVO)
- Both arterial and venous disease → Retinal Vein occlusion
- Venous occlusion = Increased Venous and cappilary pressure + Decreased blood flow
Prediposing factors?
- Age
- Hypertension: Most prevalent in BRVO ( as site of obstruction @ arteriovenous crossing)
- Hyperlipidaemia ( >6.5mmol/l)
- Diabetes
- Raised IOP ( increased CRVO risk)
Classification of BRVO?
- First order temporal branch at the optic disc (a)
- First order temporal branch away from the disc but involving the branches to the macula (b)
- Peripheral BRVO not involving the macular circulation (d, e, f)
Diagnosis of BRVO?
Symptoms?
- Symptoms depend on the amount of macular drainage compromised by the occlusion
- Patients with macular involvement often present with sudden onset of blurred vision and metamorphopsia (distort vision) or a relative visual field defect
BRVO Diagnosis
Signs on fundus?
- Dilatation
- and tortuosity of the venous segment (away from the site of occlusion
- and attenuation near the occlusion
- Flame-shaped and dot-blot haemorrhages, retinal oedema, and sometimes cotton-wool spots affecting the sector of the retina drained by the obstructed vein
Signs?
BRVO
Tutorsity of vessels
Vessels present in macula that shouldn’t be
BRVO- FFA Signs?
- variable delayed venous filling
- blockage by blood
- hyperfluorescence
- hypofluorescence
Course and Prognosis
of BRVO?
- Acute features take 6-12 months to resolve and may be replaced by:
- hard exudates
- venous sheathing and sclerosis peripheral to the site of obstruction
- slightly tortuous vessels
- Eventual visual recovery depends on:
- amount of venous drainage involved by the occlusion
- severity of macular ischaemia
Old BRVO?
Affected the superior BRV
– Hard exudates
– Venous sheathing
– Residual haemorrhages
Types pf CRVO?
- Ischaemic
- Non-ischaemic
Non- ischaemic CRVO?
Signs?
Vision defect?
Fundus appearance?
- Sudden, unilateral blurred vision.
- Afferent pupillary defect (APD) is absent or mild
- Fundus shows
- Tortuosity and dilatation of all branches of the central retinal vein
- Dot-blot and flame-shaped haemorrhages ( 4 quadrants, most numerous in periphery)
- Cotton-wool spots
- Oedema of optic disc and macula
Non-Ischaemic CRVO
Prognosis
Vision/ Visual Acuity?
- good if not become ischaemic
- Chronic macular oedema → Poor vision
- Prognosis - related to initial visual acuity:
›6/18 or better, it is likely to remain
›6/24-6/60, the clinical course variable- improve, remain the same, or worsen
›Worse than 6/60, improvement is unlikely
Ischaemic CRVO
- Sudden & severe vision loss
- Significant APD ( Afferent Pupil Defect)
- Fundus:
–Severe tortuosity
–Engorgement of all branches of the vein
–Dot-blot & flame haemorrhages
–Disc oedema
–Cotton wool spots
Artery occlusion
Common causes?
- Thrombosis/blood clot / Vessel blocked → Prevent perfusion
- Carotid embolism ( From ICA)
- Cholesterol
- Calcific
- Fibrin platelet
BRAO
Visual field loss pattern?
VA?
Fundus appearance?
FFA ( Fundus Fluorescein Angiography) ?
- Sudden altitudinal/sectoral visual field loss
- VA varies
- Fundus:
–Narrow arteries & veins
–Cloudy white retina (c/b oedema)
–Emboli can be present
- FFA:
–Delay in arterial filling
CRAO
Central Retinal Vein Occlusion?
Vision?
Afferent Visual Defect (APD) ?
Fundus?
- Sudden, severe vision loss
- APD is severe
-
Fundus
Similar to BRAO but severe
Narrow arteries & veins
Cloudy white retina (c/b oedema)
Emboli can be present
Orange reflex from intact choroid stands out in contrast to surrounding pale retina = cherry red spot
What type of Cilioretinal A. Occlusion?
Isolated
Present of haemorrhage
Papillomacular bundle occluded
What type of Cilioretinal A. Occlusion?
Signs ?
- Combined with CRVO
- Diffuse vessels
- Diffuse optic disc
- Paler area temporally
- Tortuosity of vessels
- Exudate/ harmorrage
Cilioretinal A. Occlusion
Symptoms?
Fundus signs?
- Acute, severe loss of central vision.
- Fundus signs:
- Cloudiness* localized to that part of the retina normally supplied by the vessel
Arteriolar narrowing
- Can be focal or generalised
- Hard to diagnose on ophthalmoscopy - may need OCT
- Presence of narrowing most likely = hypertension
- Severe hypertension can result in cotton-wool spots (sign of occlusion)
Vascular leakage
- Flame-shaped haemorrhages and retinal oedema
- Chronic oedema = hard exudates at the fovea (macular star)
- Swollen ON head = sign of hypertension
Arteriosclerosis ?
- Vessel wall thickens
- Changes at arteriovenous crossings (AV nipping)
- Arteriosclerosis is graded in terms of severity
Arteriosclerosis grading?
