Central Retinal Vein Occlusion (CRVO)

Primary Category

Neurovascular

P-Category

Secondary Category

S-Category

Authors:

Samar Mehdi,
Abdur Rehman,
Ayaz Khawaja MD

Introduction

Retinal vein occlusion is the blockage of one of the main veins of the retina

It is one of the commonest retinal vascular occlusive disorders

Usually associated with a variable degree of visual loss

✨

Retinal vein occlusion is the blockage of one of the main veins of the retina and is one of the commonest retinal vascular occlusive disorders, usually associated with a variable degree of visual loss.

Epidemiology

Retinal Vein Occlusion has a prevalence of 2.95%

Central Retinal Vein Occlusion (CRVO) 0.1-0.2%
Branch Retinal Vein Occlusion (BRVO) 2.74%

BRVO is 5.6 times more common than CRVO.

90% of the patients with CRVO are older than 50 years, whereas the rest are younger in age, demonstrating that incidence of CRVO increases with age.

Prevalence does not differ by gender or race.

Retinal Vein Occlusion is the most frequent retinal vascular disorder causing a visual loss after Diabetic Retinopathy.

Anatomy

Blood from the inner retina drains into the Branch Retinal Veins which drain into the Central Retinal Vein. While blood from the outer retina and the choroid drains into the vortex veins of the choroid.

The central retinal vein exits the eye with the optic nerve by passing through the lamina cribrosa. At this point, the retinal artery and vein are enclosed in a common adventitial sheath and this is the most common point of retinal vein occlusion.

The vortex veins drain into the superior and inferior ophthalmic veins.

The superior and inferior ophthalmic veins and the central retinal vein flow into the cavernous sinuses.

Blood from the cavernous sinuses enters the systemic circulation via the petrosal venous sinuses and the sigmoid sinuses, which ultimately drain into the internal jugular veins.

Risk Factors

Older age

Cardiovascular disease

Hypertension

Smoking

Obesity

Arteriosclerosis

Diabetes

Hyperlipidemia

Vasculitides

Anti-phospholipid syndrome

Activated protein C

Factor V Leiden

Hyperviscosity syndromes

Hyperhomocysteinemia

Open angle glaucoma

Autoimmunee diseases

Collagen vascular diseases

Classification

Non Ischemic CRVO

This accounts for about 75-80% of the cases of CRVO

Visual acuity is usually better than 20/400

Less than 10 disc diameters of capillary nonperfusion with fluorescein angiography

Mild retinal hemorrhages

Optic disc edema with various degrees of macular edema

Benign and self-limiting disease

Ischemic CRVO

This accounts for about 20-25% of the cases of CRVO

Visual acuity is usually worse than 20/400

10 or more disc diameters of retinal capillary nonperfusion with fluorescein angiography

Neovascularization resulting in glaucoma is most frequent with ischemic CRVO and causes additional complications

More extensive retinal hemorrhages

Gross retinal and macular edema.

Malignant disease that can get complicated by neovascularization resulting in glaucoma.

Extent of Retinal Vein Involvement

Branch retinal vein occlusion (BRVO)

Hemicentral retinal vein occlusion

Central retinal vein occlusion (CRVO)

Pathophysiology

Multiple mechanisms of venous occlusion are proposed as under,

Thickening and stiffening of the lamina cribrosa, as the person ages, may cause compression of the vascular wall.

Arteriosclerosis in the central retinal artery may compress the relatively thin walled central retinal vein as they both pass through the lamina cribrosa surrounded in a common adventitial sheath. Or, alternatively, a branch retinal vein getting compressed by a nearby arteriole is the main mechanism of BRVO.

Narrowing of the lumen of retinal vein due to above changes may result in formation of a thrombus secondary to the turbulent flow of blood. This thrombosis is the main mechanism of occlusion in CRVO.

Raised intra ocular pressure as in open angle glaucoma may cause external compression of the retinal vein compromising venous outflow or leading to formation of thrombus due to stasis.

Some evidence of local inflammatory etiology is also found.

Clinical Presentation

Signs and Symptoms

Decreased vision

Floaters

Maybe preceded by episodes of Amaurosis Fugax.

Fundus Examination

Superficial and deep hemorrhages in all four quadrants of the retina ("Tomato splash Appearance", "Blood and thunder Appearance" or "Battlefield Appearance")

Venous dilation and tortuosity

Cotton wool spots

Macular edema

Retinal detachment

Vitreous hemorrhage

Neovascular glaucoma

Differential Diagnosis

Central retinal artery occlusion (major differential)

Diabetic retinopathy

Optic neuritis

Vitreous hemorrhage

Ischemic optic neuropathy

Retinal vasculitis

Viral retinitis

Ocular ischemic syndrome

Sickle cell retinopathy

Juxta foveal telangiectasia

Investigations

Fundus Fluorescein Angiography

Normal filling of retinal and choroidal arteries

Delayed filling of retinal veins

Variable staining of the retinal veins

Variable retinal vascular leakage resulting in retinal edema

Optical Coherence Tomography

For Diagnosis and follow up of Macular edema which is an important treatable complication of CRVO

Cystic fluid filled spaces in the macula

Thickening of the retina

Submacular fluid

Electroretinography

Reduction in b wave (positive deflection in ERG)

Reduction in b/a ratio (ratio of positive deflection to initial negative deflection in ERG)

Color Doppler Imaging

To detect the onset of neovascularisation

Investigations to check for systemic diseases

Blood pressure monitoring

Hemoglobin A1C, BUN and Serum creatinine levels to check for diabetic control

Lipid profile

ESR and CRP to look for systemic inflammation

Blood coagulation studies including PT, aPTT and INR

Serum homocystein levels

ANA, Anti-dsDNA and other autoantibodies test to check for autoimmune etiology

Measurement of intraocular pressure to look for glaucoma

Management

Management specific for CRVO

Systemic anticoagulation

Antiplatelet agents

IV thrombolysis is used only if there is another known condition present e.g. antiphospholipid antibody syndrome

In cases where IV thrombolysis needs to be considered, it must be done within 4.5 hours of the onset of symptoms and after obtaining a head CT.

Surgical management includes vitrectomy with sheathotomy or radial optic neurotomy

Surgical options are not considered commonly as there is no great data to support their use

Management of complications

For symptomatic macular edema, intra-vitreal Anti-VEGF inhibitors are the first line and intra-vitreal glucocorticoids or retinal laser photocoagulation are the second line.

To deal with neovascular complications, retinal laser photocoagulation is used.

Referral to ophthalmologist

If neurologists suspect this condition then immediate referral to an ophthalmologist must be made

It is preferable to not dilate the eyes prior to an ophthalmologist's evaluation because they need to test relative afferent pupillary defect, which is an important prognostic marker of CRVO.

The neurologist should do their own comprehensive exam (for painless visual loss and neurologic exam)

The visual exam should include pupillary response, visual acuity, confrontational visual fields and extra-ocular movements.

The neurologic exam should be aimed to rule out other accompaniments of multiple sclerosis.

Follow-up of patients

Monthly exams should be done for at least 6 months if the patient has severe vision loss (visual acuity 20/400 or less). Follow up should continue beyond 6 months if complications develop.

In cases where vision loss is not severe (visual acuity better than 20/400), routine exams may be done every few months until visual acuity stabilizes

Expected prognosis

BRVO is better for visual acuity with almost 1/3rd having long-term acuity at 20/40 or higher.

CRVO is worse and prognosis depends upon the initial visual acuity. (For 20/50-20/200, 1/3rd will progress to worst acuity than 20/200, for less than 20/200, only 20% had visual acuity that improved).

Conclusion

Central retinal vein occlusion needs to be managed with a multidisciplinary approach involving neurologists and ophthalmologists.

The neurologist's responsibility is to acutely manage the patient and to evaluate whether any pertinent neurologic disorders may need to be considered

Evaluation for multiple-sclerosis, severe intracranial vascular stenosis, systemic autoimmune syndromes such as lupus or antiphospholipid antibody syndrome should be done.

The neurologist should retain a closed-loop communication with the ophthalmologist during that time.

If the diagnosis of CRVO is confirmed with fluorescein angiography, the neurologist may feel comfortable in discharging patient from their care.

Bibliography

Bhagat N, Goldberg MF, Gascon P, Bell W, Haberman J, Zarbin MA. Central retinal vein occlusion: review of management. Eur J Ophthalmol. 1999;9(3):165-180. doi:10.1177/112067219900900304

Central retinal vein occlusion: a review Ian L McAllister FRANZCO Volume 40, Issue 1Pages: 1-116, e1-e127 January/February 2012 https://doi.org/10.1111/j.1442-9071.2011.02713.x https://onlinelibrary.wiley.com/share/B6HQ6N66UP9ZRQT4XHWZ?target=10.1111/j.1442-9071.2011.02713.x

Hayreh SS. Classification of central retinal vein occlusion. Ophthalmology. 1983;90(5):458-474. doi:10.1016/s0161-6420(83)34530-9

Kanukollu VM, Ahmad SS. Retinal Hemorrhage. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560777/

Kiel JW. The Ocular Circulation. San Rafael (CA): Morgan & Claypool Life Sciences; 2010. Chapter 2, Anatomy. Available from: https://www.ncbi.nlm.nih.gov/books/NBK53329/

Prisco D, Marcucci R, Bertini L, Gori AM. Cardiovascular and thrombophilic risk factors for central retinal vein occlusion. Eur J Intern Med. 2002;13(3):163-169. doi:10.1016/s0953-6205(02)00025-0

Prisco D, Marcucci R. Retinal vein thrombosis: risk factors, pathogenesis and therapeutic approach. Pathophysiology of Haemostasis and Thrombosis. 2002 Sep-Dec;32(5-6):308-311. DOI: 10.1159/000073587. PMID: 13679663.

Quinlan PM, Elman MJ, Bhatt AK, Mardesich P, Enger C. The natural course of central retinal vein occlusion. Am J Ophthalmol. 1990;110(2):118-123. doi:10.1016/s0002-9394(14)76979-x

Rogers S, McIntosh RL, Cheung N, Lim L, Wang JJ, Mitchell P, et al. The prevalence of retinal vein occlusion: pooled data from population studies from the United States, Europe, Asia, and Australia. Ophthalmology. 2010

Sohan Singh Hayreh, Patricia A. Podhajsky, M. Bridget Zimmerman, Natural History of Visual Outcome in Central Retinal Vein Occlusion, Ophthalmology, ISSN 0161-6420, https://doi.org/10.1016/j.ophtha.2010.04.019.

Thapa, R., Bajimaya, S., Paudyal, G. et al. Prevalence, pattern and risk factors of retinal vein occlusion in an elderly population in Nepal: the Bhaktapur retina study. BMC Ophthalmol 17, 162 (2017). https://doi.org/10.1186/s12886-017-0552-x

Tomasini DN, Segu B. Systemic considerations in bilateral central retinal vein occlusion. Optometry. 2007;78(8):402-408. doi:10.1016/j.optm.2006.12.017

Williamson TH. Central retinal vein occlusion: what's the story?. Br J Ophthalmol. 1997;81(8):698-704. doi:10.1136/bjo.81.8.698

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