3. Introduction
• Common , second most common cause of blindness from retinal
vascular disease after DR.
• RVO classified according to where the occlusion is located.
• Optic nerve level (CRVO), primary superior branch or primary inferior
branch involving approximately half of retina (HRVO ),any more distal
branch of retinal vein (BRVO).
6. Pathophysiology
•RVO can be defined as retinal vascular disorder charecterized by congestion and dilation of
the retinal veins with subsequent retinal hemorrhage and edema , retinal ischemia including
cotton wool spots, retinal exudate and macular edema
9. CONT…
• Once venous occlusion has occurred, elevation of venous and
capillary pressure with stagnation of blood flow ensues, resulting in
retinal hypoxia, which in turn results in damage to the capillary
endothelial cells, extravasation of blood constituents and liberation
of mediators such as VEGF.
10. Risk factors
Risk
factors
Smoking
Hypertension
Age
Oral
contraceptive
pill. Glaucoma
Uncommon
Diabetes mellitus
Hyperlipidaemia
most important
factor; over
50% of
cases occur
in patients
older than
65
probably ocular
hypertension
are associated
with a higher
risk of CRVO
and possibly
BRVO
present in up to 15%
of patients over
50 years of age
overall., but
uncommon in
younger patients
present in one-third
or more of
patients,
irrespective of
age
present in two-thirds or
more of RVO
patients over the
age of 50 years and
in 25% of younger
patients. It is most
prevalent in
patients with BRVO
younger females the
contraceptive
pill is the most
common
underlying
association,
and probably
should not be
taken following
RVO.
11.
12. Uncommon causes
Dehydration, myeloproliferative disorders (e.g.
myeloma, polycythaemia), thrombophilia (e.g.
hyperhomocysteinaemia, antiphospholipid
antibody syndrome, factor V Leiden mutation),
inflammatory disease associated with occlusive
periphlebitis (e.g. Behçet syndrome,
sarcoidosis, Wegener granulomatosis), orbital
disease and chronic renal failure
15. Branch Retinal Vein Occlusion (BRVO)
• First described by Leber.
• One of the branches of
main vein are blocked.
Superotemporal
branch (66 %)
Inferotemporal branch
(22-43%)
Nasal branches
(0.5-2.6%)
30. Hemiretinal vein occlusion
• It is less common than either BRVO or CRVO and involves occlusion of
the superior or inferior branch of the central retinal vein (CRV).
• A hemispheric occlusion blocks a major branch of the CRV at or near the
optic disc.
31.
32.
33.
34. Hemiretinal vein occlusion
• Prognosis depends on the severity of retinal ischaemia, but
management has been less well studied than BRVO and CRVO.
• Extensive retinal ischaemia implies a risk of neovascular glaucoma
and should be managed in the same way as ischaemic CRVO,
otherwise management, particularly of macular oedema, may be as
for BRVO.
35. Impending central retinal vein occlusion
• Impending (partial) CRVO is a relatively poorly-defined condition of
patients who are either asymptomatic or who may complain of mild,
often transient episodes of blurring of vision characteristically worse
on waking and improves during the day.
• On average occurs in younger patients than those developing more
severe occlusion.
36. • The distinction between ‘impending’ and mild non-ischaemic CRVO is
not clear, and may be artificial.
• The prognosis is usually good but a proportion will deteriorate to
ischaemic CRVO
37. It appears that this disease may have the potential for
bidirectional progress
Lee, D.-H., Lee, S.-J., & Yoon, I.-N. (2010). Clinical Progress in Impending Central Retinal Vein Occlusion. Korean Journal of Ophthalmology : KJO, 24(2), 83–88.
http://doi.org/10.3341/kjo.2010.24.2.83
38. Symptoms
• They may be absent or consist of only minor or transient blurring that is
characteristically worse on waking.
39. Signs
• On examination, there is mild retinal venous dilatation and tortuosity,
with relatively few small scattered dot and blot haemorrhages
• There may be mild macular edema
41. (A) Fundus findings of slightly tortuous and engorged
retinal veins at first visit.
(B) After one month, the retinal venous tortuosity and
engorgement were no longer present
42. (A) Fundus findings of flame-shaped retinal
hemorrhage, moderated retinal venous engorgement,
cotton-wool spots and dot hemorrhage at first visit.
(B) After two months, the fundus returned to its normal
appearance.
43. FFA
• FA generally demonstrates an impaired retinal circulation. ( increase
in retinal circulation time)
• Non-ischemic CRVO, FA shows marked delay in arteriovenous transit
time, which is longer than 20 seconds, masking by retinal
haemorrhages, and vessel wall staining.
49. IschemicNon-IschemicCRVO
Worse than 6/60
Counting fingers
Better than 6/60Visual Acuity
At presentation
Severe Fall in vision
Sudden
Monocular
Painless but
occasionally with
pain, redness and
photophobia, [due
to NVG]
Fall in vision
Sudden
Monocular
Painless
Symptoms
52. Ischemic CRVO
• NVI. [Rubeosis iridis]
• About 50% of eyes
• Between 2 and 4 months a high risk of developing neovascular
glaucoma (‘One hundred-day glaucoma’),
• Gonioscopy
• Angle neovascularization may occur even in the absence of
neovascularization at the pupillary margin.
• Examination of the pupillary margin and Routine gonioscopy
should be performed at each review, prior to pupillary
dilatation.
53.
54.
55. IschemicNon-IschemicCRVO
• Patchy (or perivenular) ischaemic
retinal whitening (PIRW)
• At the posterior pole
• Early sign occurring in younger
patients with nonischaemic CRVO.
Fundus
Early
56. Fig (B) young patient with mild nonischaemic CRVO showing perivenular ischaemic retinal
whitening (PIRW), particularly noticeable in the perifoveal region
57.
58.
59. IschemicNon-IschemicCRVO
• Severe tortuosity and
engorgement of all
branches of the central
retinal vein.
• Extensive deep blot and
flame-shaped hges
involving the peripheral
and posterior retina
• Cotton wool spots are
typically prominent.
• Optic disc swelling and
hyperaemia.
• Most acute signs resolve
over 9–12 months.
• Signs are present in all
quadrants.
• Tortuosity and dilatation of
all branches of the central
retinal vein
• Less Dot, blot and flame
haemorrhages
• Cotton wool spots [to a
mild–moderate extent]
• Optic disc and macular
oedema are [common] but
generally [mild].
• Most acute signs resolve
over 6–12 months
Fundus
Acute
60. Nonischemic CRVO:
•Scattered intraretinal
hemorrhages, mild optic Nerve
head edema and hyperemia, and
dilated and tortuous veins.
•No significant macular edema.
Ischemic CRV
Extensive intraretinal
hemorrhages.
Vasculature is barely
discernable.
Cystoid macular edema
61. Fig. Recent ischaemic central retinal vein occlusion. (A) Numerous cotton
wool spots, flame and deep blot haemorrhages
62. Fig. Non-ischaemic CRVO (A) Acute – wide-field image showing venous
tortuosity and dilatation, with moderate flame haemorrhages and at least
one cotton wool spot
63. IschemicNon-IschemicCRVO
• Atrophic retinal and RPE
changes
• RPE hyperplasia
• Epiretinal membrane
• Chronic CMO.
• Subretinal fibrosis [rare]
resembling that associated
with exudative AMD may
develop.
• Retinal neovascularization (5%
of eyes) – much less commonly
than with BRVO
• Severe vitreous haemorrhage
can occur, obscuring vision and
preventing retinal laser.
• Variable findings,
depending on severity
• Persistent scattered
retinal haemorrhages
• Venous tortuosity
• Sheathing and sclerosis
• Epiretinal gliosis
• Macular pigmentary and
atrophic changes
• Peripheral collateral
vessels.
Fundus
Late
64.
65.
66. IschemicNon-IschemicCRVO
• Optic disc collaterals are
common
Disc collaterals /
Optociliary shunts/
Retinochoroidal collaterals
• Common following CRVO.
Fundus
Late
A small vascular loop on the optic nerve head
Thought to represent a compensatory circulation in response to
impaired nerve perfusion;
Their development is believed to be associated with a markedly
decreased risk of neovascularization.
They can form in a range of conditions besides CRVO, including
chronic glaucoma and chronic optic nerve compression.
May protect the eye from anterior and posterior segment
neovascularization; their development probably indicates a dramatic
reduction in the risk of this complication.
67. Fig. Non-ischaemic central retinal vein occlusion (CRVO).
(C) non-acute – disc collaterals and a few residual retinal
haemorrhages
74. IschemicNon-IschemicCRVO
•Extensive areas of capillary
non-perfusion (<10 dd) and
vessel wall staining and
leakage.
•Blocked flourescense capillary
drop-outs
•Marked delay in arteriovenous
transit time (>20sec), masking
by retinal haemorrhages
•The presence of > 10 dd of
retinal capillary non-perfusion
is associated with a
substantially increased risk of
neovascularization.
•Good perfusion
•Venous stasis
•Absent capillary drop-
outs
•Delayed
arteriovenous transit
time, masking by
haemorrhage
•Some late leakage.
FFA
75. Delayed filling of the retinal venous system in a CRVO. This frame, taken 14
second after the appearance of fluorescein in the retinal arteries, shows
minimal filling of the retinal venous system
77. Large capillary aneurysms that occurred after a CRVO.
Peripheral to the aneurysms is a large area of nonperfusion
78. Fig. Non-ischaemic central retinal
vein occlusion (CRVO).
(D) FA late phase in a recent onset
case shows masking by blood and
staining of vessel walls but good
capillary perfusion
Fig. Recent ischaemic central
retinal vein occlusion.
(C) FA shows extensive
hypofluorescence due to capillary
non-perfusion
79.
80. • Fundus photograph of a central retinal vein occlusion demonstrating
typical features of venous tortuosity, macular thickening, and intraretinal
hemorrhage in all four quadrants of the fundus. (B) Early-phase
angiogram of the fundus depicted in A, demonstrating an intact
parafoveal capillary network in this non-ischemic central retinal vein
occlusion.
81.
82. (A) Fundus photograph of an eye with central retinal vein occlusion
demonstrating scattered retinal hemorrhages, venous engorgement,
and cotton-wool spots. (B) Midphase fluorescein angiogram of the
eye shown in A, demonstrating capillary nonperfusion involving the
foveal center.
• This eye also had extensive peripheral nonperfusion and is an
example of the ischemic form of central retinal vein occlusion.
84. Fig. Recent ischaemic central retinal vein occlusion. (D) wide-field FA
showing extensive peripheral ischaemia
85. IschemicNon-IschemicCRVO
•May show a
characteristic fern-like
perivenular
hypoautofluorescence
•Due to masking of
background signal by
oedema; it corresponds
to PIRW, but is more
commonly identifiable
FAF
CommonRareVF defect
86.
87. IschemicNon-IschemicCRVO
depressed and
the extent of
this has
sometimes been
used to assess
neovascular
risk.
Normal or near
normal
ERG
Enables
quantification of
CMO.
Assessment of CMO,
which is often mild in a
non-ischaemic lesion.
OCT
90. Fig. Treatment of
central retinal vein
occlusion (CRVO)
complications. (A) CRVO
before and (B) 6
months after
intravitreal
dexamethasone
implant
91. Fig. Treatment of central
retinal vein occlusion
(CRVO) complications. (A)
CRVO before and (B) 6
months after intravitreal
dexamethasone implant
92. IschemicNon-IschemicCRVO
High riskLow riskRisk of
neovascularization
NVI, NVG,
NVE/NVD
Chronic CME
Around a third will
progress to ischemic
CRVO, often within
months.
Complications
60%Rubeosis
and NVG
Macular ischaemia
and NVG are the
major causes of
visual morbidity.
50% Better than 6/60
VA worse than 6/60 commonly
indicates that substantial
ischaemia is present.
In cases that do not become
ischaemic, vision returns to
normal or near normal in 50%.
Prognosis
93.
94. Papillophlebitis
• Some mild CRVOs in patients younger than 50 years
• Most propably the cause is an inflammatory optic neuritis or
vasculitis
• These eyes tend to have:
• Optic disc edema out of proportion to the retinal findings
• Cotton-wool spots that ring the optic disc
• Occasionally cilioretinal artery occlusions
• or Partial central retinal artery occlusions
• Spontaneous improvement is common.
• BUT up to 30% of these patients may develop the ischemic type of
occlusion with a final visual acuity of 20/200 (6/60) or worse.
105. Perform OCT & FA @ 3months
•VA < 0.5 with Macular Edema
• Grid laser photocoagulation
• Intravitreal anti-VEGF if grid laser treatment failure or in eyes
with extensive macular hemorrhage
•VA > 0.5
• Consider intravitreal anti-VEGF as primary treatment
•If 5 disc diameter of non-perfusion is seen
• close follow-up looking for NV
•Once new vessels are seen
• Sector Argon photocoagulation
106. Other treatment modalities
• IVTA
• Does not improve VA in macular edema
• Significant side effects of raised IOP and cataract
• Dexamethasone implant
• Improves VA in macular edema
• Side effects of raised IOP and cataract
• PPV with AV sheathotomy
Tow thirds of ischemic pt develop macular edema macular ischemia neovascularization
Retinal arteriol and venolnshare a common adventitial sheath
Secondry changes
HRGE EDEMA
OCULAR AND SYSTEMIC
MORE 9N MEN THAN WOMEN
BRVO :
BRVO is a common retinal vascular disorder of the elderly, at least three times more common than CRVO.
No racial or gender predilection
Usual age…5th-6th decade
BRVO occurs at arteriovenous crossing site.
This observation is attributed to Leber, a German ophthalmologist, who over 100 years ago first suggested the vulnerability of arteriovenous crossing and the importance of arteriosclerosis in the pathogenesis of BRVO.
Nasal quadrant BRVOs are likely under-represented as most are asymptomatic and thus these patients might not seek ophthalmic attention.
Up to two thirds of BRVOs occur in the supero-temporal quadrant. This may be related to the increased number of arterio-venous crossings in this quadrant with respect to the rest.
Multifactorial :
Most epidemiological and histopathological evidence implicates arteriolar disease as the underlying pathogenesis.
BRVO almost always occurs at an arteriovenous crossing, where the artery and vein share a common adventitial sheath. The artery typically is anterior (innermost) to the vein.
Rarely, local ocular diseases, especially of an inflammatory nature, can result in a secondary BRVO. This has been reported in diseases
such as toxoplasmosis, Eales’ disease, Behçet’s syndrome, and ocular sarcoidosis. Macroaneurysms, Coats’ disease, retinal capillary hemangiomas,
and optic disc drusen are also linked to BRVO.
Symptoms
if the central macula is involved consist of the sudden painless onset of blurred vision and metamorphopsia.
Peripheral occlusion may be asymptomatic.
Patients with BRVO usually complain of sudden onset of blurred vision or a visual field defect.
VA at presentation is very variable.
Historically 50% of untreated eyes retain 6/12 or better in the long term, but about a quarter only achieve 6/60 or worse.
Visual loss from a BRVO usually is caused by macular edema, macular ischemia, or vitreous hemorrhage.
Visual acuity may range from 20/20 (6/6) to counting fingers.
Occasionally a partial BRVO with little hemorrhage and edema may progress to a complete BRVO, with an increase in hemorrhage and edema with
a corresponding decrease in visual acuity.
Retinal neovascularization occurs in approximately 20% of cases but anterior segment neovascularization (NVI/NVA) and neovascular glaucoma
(NVG) are exceedingly rare, in contrast to CRVO (2–3% at 3 years).
Dilatation and tortuosity of the affected venous segment.
flame-shaped and dot/blot haemorrhages, principally in the retinal area drained by the thrombosed vein though an occasional haemorrhage may be identified elsewhere; (Flame-shaped intraretinal hemorrhages confined to the distribution of a retinal vein are characteristic)
cotton wool spots and retinal oedema may be absent but are often prominent.
The acute features usually resolve within 6–12 months leaving venous sheathing and sclerosis, and variable persistent/recurrent haemorrhage, the severity of residual signs is highly variable.
The distribution of the hemorrhages usually assumes a triangular configuration with the apex at the site of blockage. Mild occlusions are associated with a relatively small amount of hemorrhage while complete occlusions result in extensive hemorrhages, cotton wool spot formation, and widespread capillary nonperfusion.
Over time, the clinical features of an acute BRVO can become more subtle so that the fundus can look almost normal.
Branch retinal vein occlusion: Retinal hemorrhage in only a sector of the retina is seen. Superotemporal Quadrant of the Right Eye.
Cotton-wool spots (white lesions amid the hemorrhages)
signify focal ischemia (inadequate blood supply).
Foveal edema (swelling with fluid) is also present.
The incidence of retinal neovascularization rises with increasing area of retinal nonperfusion.
Retinal neovascularization typically develops within the first 6–12 months but may occur years later.
Vitreous hemorrhage and tractional retinal detachment can result, which may require vitrectomy.
Microaneurysm formation and lipid exudation may also be present. .
Collateral vessels and microvascular abnormalities usually develop. Collateral vessels crossing the horizontal raphe are a salient feature of BRVO and their presence should prompt consideration of remote BRVO.
The retinal vein may become sclerotic proximal to the site of blockage while the retinal artery that feeds the affected zone may become narrowed and sheathed. Epiretinal membrane and macular retinal pigment epithelial changes as a result of chronic CME sometimes are seen in the late phase of a BRVO.
Collateral vessels may form near areas of limited capillary perfusion after weeks to months. They usually connect a poorly functioning to a normally functioning segment of the venous circulation, and typically appear as tortuous or looping channels. They may cross the horizontal raphe
between the inferior and superior vascular arcades. The appearance of collaterals is associated with a better prognosis; ablation of collaterals should be avoided if laser is performed.
Chronic macular oedema is the most common cause of persistent poor visual acuity after BRVO.
Retinal neovascularization occurs in about 8% of eyes by three years; the risk is much higher in eyes with more than about 5 disc areas of non-
perfusion on FA (over one-third of eyes). NVE are more common than NVD.
NVE usually develop at the border of ischaemic retina drained by an occluded vein; they typically appear within 6–12 months but may develop at any time.
Recurrent vitreous and preretinal haemorrhage, and occasionally tractional retinal detachment, can occur secondary to neovascularization.
FA demonstrates peripheral and macular ischaemia (capillary non-perfusion, staining of vessel walls, vessel ‘pruning’ – small branches failing to fill – Fig. 13.27C), haemorrhage and oedema (Fig. 13.27D) with collateral vessels commonly forming in established cases (Fig. 13.27E). Venous filling is
delayed. In late or subtle cases FA may be diagnostic.
• OCT allows quantification of macular oedema.
Branch Retinal-Vein Occlusion in the Superotemporal Quadrant of the Right Eye.
A fundus photograph (Panel A) shows a sectoral area of dilated veins, retinal hemorrhages (white arrows), cotton wool
spots (black arrows), and retinal edema,
and a fluorescein angiogram (Panel B) reveals blockage (white arrows) and leakage of dye (yellow arrows).
Optical-coherence tomographic scans (horizontal scan in Panel C and vertical scan in Panel D) show retinal thickening (white arrows), as compared with normal retinal thickness (black arrow), and macular edema (yellow arrows). N→T denotes a nasal-to-temporal cut of the retinal scan, and I→S an inferiorto-
superior cut.
Inferotemporal branch retinal vein occlusion.
(A) Acute – flame-shaped and blot haemorrhages,
cotton wool spots and venous tortuosity;
(B) 6 months later – venous sheathing, a few exudates and residual
haemorrhages, with collaterals at the temporal macular
edge;
(C) early FA image of the acute occlusion principally showing capillary non-perfusion with some blockage by
blood;
(D) later image clearly demonstrates vessel wall staining, pruning and non-perfusion
Compensated BRVO – disc collaterals
Old BRVO with TRD involving macula
BRVO with macular edema.
Well compensated BRVO 6months after avastin
Branch retinal vein occlusion treated with focal laser.
(A) Fundus photograph of localized intraretinal hemorrhages and cotton-wool spots in a segmental
distribution along a superotemporal retinal vein.
(B) Corresponding optical coherence tomography and thickness map reveal macular edema. (C) Fundus photograph 2 years
following treatment with focal grid laser photocoagulation to area of leakage shows resolution of hemorrhage. (D) Corresponding optical coherence tomography and thickness map show resolution of macular edema.
Branch retinal vein occlusion treated with combination focal laser and intravitreal bevacizumab.
(A) Fundus photograph of intraretinal hemorrhages and cotton-wool spots along the inferotemporally retinal vein.
(B) Corresponding optical coherence tomography and thickness map reveal significant macular edema.
(C) Fundus photograph 6 months following combination treatment with focal grid laser photocoagulation and intravitreal bevacizumab.
(D) Corresponding optical coherence tomography and thickness map show resolution of macular edema with mild infratemporal retinal thinning. (Images courtesy Caroline R. Baumal, MD.)
Hemiretinal vein occlusion is regarded as a variant of CRVO by some authorities and may be ischaemic or non-ischaemic.
Symptoms : A sudden onset altitudinal visual field defect .
VA reduction is variable.
NVI is more common than in BRVO but less than in CRVO.
Inferior altitudinal visual field defect due to a superior hemiretinal vein occlusion;
Fundus shows the features of BRVO, involving the superior or inferior retinal hemisphere.
NVD may be more common than in either CRVO or BRVO.
FA shows masking by haemorrhages, hyperfluorescence due to leakage and variable capillary non-perfusion
B) inferior hemiretinal vein occlusion; (C) FA late phase shows extensive hypofluorescence due to capillary non-perfusion, with mild perivascular hyperfluorescence
An 18-year-old male patient with no specific history was admitted due to complaints of amaurosis fugax in his left eye. Blood test and neurologic exam did not reveal any abnormality. The initial LogMar vision was 0.2. On fundus examination, venous tortuosity and dilation in the central retinal vein were found. He was followed for one month without any particular treatment. The LogMar vision after one month was improved to 0.0, and venous tortuosity and congestion in the central retinal vein disappeared completely (Fig 1).
A 31-year-old male patient with complaints of mild vision loss in his left eye visited the hospital. No specific history was discovered. Blood test and neurologic examination showed no specific finding. The initial vision was LogMar 0.2, and on fundus examination, venous tortuosity, venous dilation, dot hemorrhages, and cotton-wool spots were observed. The patient was followed for two months without treatment, after which his vision improved to 0.0 and the previously observed central vein and retinal lesions improved
Fluorescein angiography (Figure 1) disclosed delayed filling of the central retinal vein and prolonged arteriovenous filling time, without capillary nonperfusion. Blood pressure was 120/70 mmHg. A systemic workup did not reveal any underlying disease. No specific treatment was performed. One week later, best-corrected visual acuity in the right eye was 20/20. Funduscopy of the right eye was normal. Three months after the first evaluation, visual acuity and funduscopic examination were unchanged. Fluorescein angiography revealed normal dye transit time as well as no abnormal fluorescence (Figure 2).
