Central Retinal Vein Occlusion (CRVO)

*Please note that this information is for illustrative purposes only, providing a general overview on the topics listed. For any specific questions or concerns regarding your condition, please contact our office so that you can consult with the appropriate person or department to address your needs.

Central Retinal Vein Occlusion (CRVO)

A central retinal vein occlusion (CRVO) occurs suddenly or slowly and progressively, from the development of a thrombus, or clot, within the lumen of the central retinal vein within the optic nerve head.  Blood enters the eye through the central retinal artery that comes out of the center of the optic nerve.  Blood then flows through the four retinal arteries, into smaller retinal arterioles and into capillaries where oxygen is exchanged into the retinal tissues.  The blood then flows from the capillaries to the smaller retinal venules and into one of the four large retinal veins.  Each of these four retinal veins flow into the central retinal vein in the optic nerve.   

In some patients, a thrombus or clot forms in the central retinal vein and blocks the blood from exiting the retina.  Back pressure then builds up in the four retinal veins which causes these veins to dilate and become more tortuous.  The pressure also builds up in the retinal venuoles and capillaries and causes blood and serum (fluid) to leak out of the retinal capillaries into the retinal tissues in the macula (center of the retina) and peripheral retina.

There are two types of CRVO’s.  Non-ischemic CRVO’s (80% of cases) where your retinal circulation is mostly intact and ischemic CRVO’s (20% of cases) where the occlusion is so severe that there is permanent loss of capillaries in the microcirculation in the macula and peripheral retina.  

Ischemic CRVO’s can lead to the development of abnormal growth of blood vessels in the back to the eye on the optic nerve (neovascularization of the disc/NVD) or retina (Neovascularization elsewhere on the retina/NVE).  These new blood vessels are weak and can rupture open and cause a Vitreous Hemorrhage (VH) to develop.  

Ischemic CRVO’s can also lead to development of abnormal growth of blood vessels in the front of the eye on the iris (Rubeosis Iridis) and over the trabecular meshwork (drain for fluid to exit the eye).  When the trabecular meshwork gets blocked aqueous fluid cannot get out of the eye and the intraocular pressure increases causing a condition called Neovascular Glaucoma or (NVG).


The development of a Central Retinal Vein Occlusion (CRVO) causes symptoms such as the sudden onset blurry vision or loss of vision, sometimes associated with new floaters. The visual loss typically affects central vision and all peripheral visual fields.

Diagnostic Testing

Optical Coherence Tomography (OCT) is used to evaluate the macular anatomy and to rule out cystoid macular edema in CRVO patients (see sample OCT).

Fluorescein Angiography (FA) is used to evaluate the macular and peripheral circulation.  Many patients with ischemic and non-ischemic CRVO’s have a delay in dye filling the retinal arteries and veins because of slowing in the retinal circulation associated with the blockage in the central retinal vein.   Patients with ischemic CRVO’s also demonstrate loss of capillary circulation in the center of the retina (macular ischemia) and dropout of capillaries in the peripheral retina (peripheral ischemia).

Iris Angiography (IA) is used to evaluate the anterior part of the eye to rule out the growth of new blood vessels on the iris (NVI or Rubeosis Iridis) that can develop in patients with ischemic CRVO’s


The treatment of a non-ischemic CRVO includes a complete medical work-up looking into underlying causes of venous occlusive disease and coagulopathies.

The treatment of ischemic CRVO’s include panretinal photocoagulation (PRP) for patients who present with neovascularization of the disc (NVD), neovascularization elsewhere in the retina (NVE), neovascularization on the iris (NVI), and neovascular glaucoma (NVG).

The treatment for cystoid macular edema caused by a CRVO includes anti-VEGF therapy such as Avastin, Lucentis and Eylea therapy and steroid therapy such as Ozurdex and triamcinolone (Kenalog or Triessence).

Surgical Treatment Options

Vitrectomy surgery is not a treatment for a CRVO unless there is an associated vitreous hemorrhage that prevents placement of adequate panretinal photocoagulation (PRP) in patients with ischemic CRVO’s or rubeosis iridis (NVI).

The procedure is performed under local anesthesia, in an outpatient surgical center or hospital. The surgery is performed through three 25-gauge ports (about the width of a wire paper clip).  The surgery begins by placing an infusion canula, a light pipe & a vitrectomy cutter through each of the 3 ports.  The infusion cannula keeps a constant pressure in the eye while the vitrectomy cutter removes the vitreous gel and vitreous hemorrhage.  As the gel is removed, balance salt solution replaces the gel in the vitreous cavity.  The gel that is adherent to the retina is gently lifted off the optic nerve and macula to separate the vitreomacular adhesions.  The light pipe is used by the surgeon to see the vitreous being removed inside the eye.  After the hemorrhage and gel are removed, the surgeon will place panretinal photocoagulation (PRP) in the peripheral retina.  The surgeon removes the surgical instruments and trocars (3 ports) and the operation is complete.  No sutures are typically needed in up to 95% of cases. Antibiotic ointment and a patch are placed over the eye for one night and removed the following day in our office.​

Risks and Benefits of Surgery

Some of the benefits of vitrectomy surgery are the potential for improved vision, placement of a full panretinal photocoagulation (PRP) treatment and reduction or elimination of new blood vessel growth (NVD, NVE & NVI).   Some of the risks of vitrectomy surgery include:
  • More rapid cataract progression (in up to 20% of patients the lens may harden or become cloudy more rapidly after the vitreous gel is removed) that may require cataract surgery 1-2 years after the vitrectomy procedure.
  • Vitreous (less than 5%) or choroidal (less than 1%) hemorrhage
  • Retinal break or tear (less than 5%) or Retinal Detachment (less than 1%)
  • Infection/Endophthalmitis (less than 1 in 500 patients)
  • Permanent loss of vision/Blindness
These are some of the more common and serious side effects of surgery, but there are also additional risks of surgery not listed above.

Post-Operative Care

Patients are typically started on antibiotic and steroid eyedrops the day after surgery. The frequency of these drops will be determined by your surgeon on the first post-operative day.  Some patients have a temporary increase in intraocular pressure after even uncomplicated surgery and may require additional pressure lowering drops or oral medication.

Post-Operative Expectations

Vision is usually blurry the first day after surgery but typically improves to equal or better than your pre-operative vision about a week after surgery.  Continued visual improvement often occurs over the first 6-8 weeks but some patients experience improvement even up to 6 months after surgery. Vision may be limited by poor circulation in patients with ischemic CRVO’s.

Patients typically experience little to no pain following surgery.  Surface or external irritation (feeling of having something in your eye) is common.  A deeper or more intense eye pain is not typical and may signal a more serious issue such as high intraocular pressure, serous or hemorrhagic choroidals or infection.  A deeper or more intense eye pain needs to be reported to you physician immediately.

Post-Operative Restrictions

Post-operative restrictions are for 4 weeks after surgery and include:
  • Please try to refrain from anything that creates a Valsalva Maneuvers such as coughing, sneezing, blowing your nose, straining with bowel movements or exertion.
  • No bending at the waist putting your head below your belt line (such as bending to tie your shoes).  Bending at the knees with your head up is allowed.
  • No heavy lifting greater than 15-20 lbs.
  • No strenuous activity (including lifting weights, running, yoga, pilates, aerobics, yard work, snow shoveling, laundry, housecleaning, sexual intercourse) is not recommended as it will increase your risk of developing a retina tear or detachment.  Walking, for exercise, after surgery is allowed (in patients who do not require post-operative head down position).
  • Showering is allowed immediately after surgery, but please be sure to keep your eyes closed to prevent shower water from entering your eye.
  • Swimming after surgery should be avoided for 4 weeks.  You may stand in a pool, but you are not allowed to go under water for the first 4 weeks.
  • Working restrictions are job dependent.  Patients with desk jobs or who perform light stationary office work may sometimes resume work 2-3 days after surgery.  Patients with jobs that require heavy lifting or strenuous activity may be required to be out of work for 2-4 weeks.  Ask your physician about your individual work restrictions.  We will be happy to provide you with a doctor’s note for your work and/or complete your temporary disability paperwork.
  • Driving restrictions will be dependent on your post-operative vision and should be discussed with your physician after surgery.

*Please note that this information is for illustrative purposes only, providing a general overview on the topics listed. For any specific questions or concerns regarding your condition, please contact our office so that you can consult with the appropriate person or department to address your needs.