Central retinal vein occlusion (CRVO) occurs when there is a thrombus in the central retinal vein, blocking blood flow and oxygen to the retina. It is a leading cause of vision loss in older adults. CRVO can be non-ischemic or ischemic depending on the extent of blood flow reduction. Risk factors include hypertension, diabetes, hyperlipidemia, and certain blood disorders. Current treatments focus on managing complications like macular edema with anti-VEGF drugs and neovascularization with laser therapy or surgery. Prognosis is generally poor for ischemic CRVO without treatment. Close monitoring is needed to detect complications and guide further management.

1. CENTRAL RETINAL VEIN
OCCLUSION(CRVO)

2. CRVO
CRVO IS AN IMPORTANT CAUSE OF VISUAL LOSS AMONG OLDER
ADULTS THROUGHOUT WORLD.
CRVO OCCURS DUE TO THROMBUS WITHIN THE CENTRAL RETINAL
VEIN AT THE LEVEL OF THE LAMINA CRIBROSA OF THE OPTIC
NERVE.

3. Risk factors and causes of CRVO
Systemic-hypertension
Diabetes mellitus
Cardiovascular disease
Hyperlipidemia
Open-angle claucoma
Blood dyscrasias such as:
Leukemia
Lymphoma
Paraproteinemias
Waldenstrom macroglobulinemia
Multiple myeloma
Cryoglobulinemia
•Polycythemia vera

4. Risk factors and causes of CRVO
Oral-contraceptive
Diuretics
Hyperhemocysteinemia
 protein S deficiency
Protein C deficiency

5. Thrombosis of the central retinal vein at and posterior to the
level of the lamina cribrosa.
In some cases, a thickened central retinal artery may impinge
on the central retinal vein turbulence Endothelial
damage thrombosis
Histologic studies:

6. Evaluation of CRVO: non ischemic- ischemic
Careful clinical examination
V.A
RAPD
SLE
Funduscopy (90-78 – indirect funduscopy)
Gonioscopy specially in F/U
Check IOP

7. IN CRVO VISION LOSS IS MOST COMMONLY
SUDDEN:
Mild vision loss nonischemic CRVO
Severe vision loss ischemic CRVO
Less commonly, patients may experience premonitory
symptoms of transient visual obscuration before overt
retinal manifestations appear.

8. NONISCHEMIC CRVO (MILD)
PARTIAL CRVO
VENOUS STASIS RETINOPATHY
Blurred –vision
No RAPD
Mild V-field defect
Mild dilation and tortuosity of all branches of central
retinal vein.
Dot and flame shaped hemorrhages in four quadrant
of retina.
Mild macular edema
Mild optic disc swelling

9. Ischemic CRVO or severe CRVO
Complete CRVO
Non perfused CRVO
Hemorrhagic retinopathy
Decrease V.A
RAPD: +
Marked venous dilation
Severe splinter and dot hemorrhage in four
quadrant
Cotton-wool spots
Macular edema

12. Hemi CRVO considered a variant of CRVO, is
associated with a congenital variation in
central vein anatomy; it may involve either the
superior or inferior half the retina.

13. Paraclinic ischemic CRVO
Prolonged retinovascular circulation times.
Widespread CNP (at least 10 disc areas)
OCT
Visual – field: dense central scotoma
ERG: decrease b-to a- wave amplitude ratio due to
inner retinal- ischemia
Ultra wide field angiography
F.A:

17. Differential diagnosis of CRVO:
Hyperviscosity retinopathy generally bilateral
Hypertensive retinopathy
Ocular ischemic syndrome

18. Ocular ischemic-syndrome
Conj-injection
Cataract
Rubeosis-iridis
Funduscopy:
Venous dilation
M.A
Mid peripheral intraretinal
hemorrhages
Attenuated arterioles

19. F.A in ocular ischemic syndrome:
Prolonged arm –to-retina circulation time
Patchy choroidal filling pattern.
Ophthalmodynamometer:
CRVO will have normal artery pressure.
Ocular ischemic syndrome will have low artery pressure.

20. Ocular ischemic syndrome

21. CURRENT TREATMENT IS DIRECTED AT
SECONDARY COMPLICATIONS OF CRVO
THAT AFFECT VISION, INCLUDING:
Macular edema
Retinal neovascularization
NVI
NVG
R.D
Macular ischemia (CNP) another cause of visual loss in CRVO
haven’t effective treatment.
Treatment also involves management of predisposing risk
factors, such as diabetes, hypertension and hyper-lipidemia.

22. Prognosis of ischemic CRVO:
The central vein occlusion study (CVOS) showed:
Visual prognosis in generally poor
Only approximately 10% of eyes achieving vision
better than 20/400.

23. VERY ISCHEMIC CRVO ANT-SEGMENT.
NEOVASCULARIZATION (IRIS AND ANGLE) 60%
OF CASES NVG
3-5 MONTHS AFTER THE ONSET OF SYMPTOMS
Risk factors for NVG
Iris-neovascularization in CRVO
Large areas of CNP
Massive intraretinal and preretinal hemorrhage
Cotton wool spots

24. In the absence of treatment, should be
monitored on a monthly for at least 6.0Ms
Follow up:
For the progression of CRVO
For the development of Ant-Seg-neovascularization
and NVG
In the patients treated with anti-VEGF agents should
be observed for a similar duration after D/C of the
drugs.

25. TREATMENT OF MACULAR EDEMA:
Intravitreal anti-VEGF agents is currently first line
therapy for macular edema
Intravitreal steroid therapy is considered an
alternative for patients with edema refractory to anti-
VEGF monotherapy.

26. Based on CRUISE study
GALILEO
COPERNICUS
Ranibizumab
Bevacizumab
aflibercept
Are effective for macular edema in CRVO
patients.

27. ANTERIOR SEGMENT NEOVASCULARIZATION:
patients with anterior segment neovascularization are
at risk of neovascular glaucoma.
Prophylactic scatter retinal photocoagulation is
recommended to reduce this risk in patients with NVI
( the effect of laser take 2 to 4 weeks to develop).

28. CVOS recommendation:
Waiting until undilated gonioscopic examination
revealed at least 2 clock-hours of Iris
neovascularization before performing PRP.
PRP is often performed at the first sign of NVI,
particularly when close F/U in not possible
CVOS the central vein occlusion study
Laser surgery for CRVO

29. Nonclearing VH after 3Ms
Vit-H +N.V.I or NV
Persistent NVG: glaucoma surgery (glaucoma valve)
PARS PLANA Vitrectomy Surgery