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CRVO - Central
Retinal Vein
Occlusion Treatment
Jeffrey N. Weiss, M.D. , formerly Chief of Vitreoretinal Surgery at the Joslin
Diabetes Center, Faculty member at Harvard Medical School and a Visiting Scientist at the
Massachusetts Institute of Technology, has developed an operation to improve the eyesight
of patients with Central Retinal Vein Occlusion.
The retina of the eye is the sensory organ for vision. If the eye is compared to a
camera, the retina would be the film where the “picture” is formed. Proper
blood circulation is needed for the retina to function. Normally, blood flows into the
retina through the Central Retinal Artery and leaves the eye through the Central Retinal
Vein. Both of these blood vessels enter the eye through the optic nerve.
Central Retinal Vein Occlusion (CRVO) is caused by a blood clot in the vein that
drains the blood from the retina of the eye. The arterial blood enters the retina but
cannot leave it due to a blockage in the vein.
As a result, blood and fluid are backed up into the retina, which causes a loss in
vision. With further damage, the blood vessels in the retina may close leading to further
visual loss with the possible development of new abnormal blood vessels.
These new vessels may cause a very painful type of glaucoma and lead to blindness.
Traditionally, there has been no reliably effective treatment to prevent the loss of
vision or to improve vision once it is lost.
Patients with high blood pressure, diabetes, or glaucoma are at an increased risk
for developing CRVO. One researcher estimates that approximately 60,000 people
develop a CRVO each year in the United States.
AN EXPERIMENTAL TREATMENT FOR CRVO
*Tissue plasminogen activator (tPA) is a well known “clot busting” medication
successfully used for treating heart attack and stroke patients.
*Dr. Weiss has developed the instruments to allow tPA to be directly injected into the
retinal vein.
*The tPA causes the clot to dissolve, which helps blood flow through the Central Retinal
Vein.
*The operation is performed on an outpatient basis and takes approximately one hour.
WHAT ARE THE RESULTS?
Forty-five patients have undergone this experimental procedure: of the 39 cases with at
least 3 months of follow-up data, 19 (49%) have experienced at least a 2-fold improvement
in visual acuity, while 10 experienced smaller degrees of visual improvement or remained
stable. Only 10 patients (26%) experienced a decrease in vision, which compares favorably
to the natural history of CRVO where the risk of losing vision may be as high as 80%.
Some of the more remarkable results include:
1) Recovery of vision from 20/400 (legally blind) to 20/40 (usual legal limit for driving
an automobile) within 2 months following the surgical procedure, and 20/20 vision 4 months
later;
2) an improvement in vision from 20/60 to 20/25 (4 lines) within 2 months following the
procedure;
3) an improvement in vision from “count fingers” (just being able to discern how
many fingers are held in front of one’s face) to 20/100 within one week following the
procedure; and
4) a 7-line improvement in vision in a patient who had a severe CRVO for at least 4 months
before the surgery.
These results are very encouraging and shows this procedure may help recover vision
which has been lost following CRVO. We presented our technique at the American Academy of
Ophthalmology Annual Meeting in October 2000 and will present it at the Association for
Research in Vision and Ophthalmology (ARVO) Annual Meeting on May 3, 2001.
While we have had very positive results even in eyes with longstanding CRVO, the final
visual acuity achieved following this procedure may be related to the duration of CRVO and
the preoperative visual acuity. Therefore, if you are considering having the procedure, it
is better to decide early, before the CRVO has progressed and caused irreversible damage
to the retina.
FOR MORE INFORMATION
*Telephone the Retina Associates of South Florida Monday through Friday from 9AM –
4PM EST, at 954-975-0044 and ask for Mr. Anthony Lobacz, the CRVO Study Coordinator.
*In order for you to avoid unnecessary travel time and costs, the Retina Associates of
South Florida will review your ophthalmic records (at no charge) to determine if you would
be a candidate for the procedure. For those patients traveling from outside Florida, our
office will assist you in making the travel arrangements.
DO YOU WANT TO HELP?
To build on our success in treating CRVO and to expand on the availability of our
breakthrough procedure within the medical community, we have started the Weiss Eye
Research Foundation, Inc. This non-profit organization was created to support our research
activities in central retinal vein occlusion and other retinal vascular disorders. Our
immediate goal is to develop or procure the research equipment that will allow us to
directly measure the flow inside the retinal blood vessels. We also require funds to
compensate research staff. If you would like to make a donation, please click here. All
donations are fully tax-deductible and will be greatly appreciated.. Donations should be
sent to:
The Weiss Eye Research Foundation, Inc.
5800 Colonial Drive, Suite 300
Margate, FL 33063
Be sure to include your address so receipts can be mailed to you. For your added
convenience, donations can easily be made by credit card through our secure server (we
accept Visa, MasterCard, American Express, and Discover). Thank you for your support!
REFERENCES
1. Weiss JN, Bynoe LA. Injection of tissue plasminogen activator into a retinal vein in
eyes with central retinal vein occlusion, manuscript submitted.
2. Guttman, Cheryl. Injection of t-PA helps CRVO patients recover vision. Ophthalmology
Times Feb. 15, 2001;26/4:28-29.
3. Weiss JN, Bynoe LA. Tissue plasminogen activator injection into a retinal vein in
patients with central and hemispheric retinal vein occlusion. Paper presentation,
American Academy of Ophthalmology Annual Meeting, October 25, 2000, Dallas, Texas.
4. Weiss JN. Retinal surgery for treatment of central retinal vein occlusion. Ophthalmic
Surgery and Laser 2000;31:162-165.
5. Weiss JN. Injecting t-PA in a branch retinal vein helps some CRVO patients.
Ophthalmology Times Feb. 1, 1999;24/3:16/21.
6. Weiss JN. Treatment of central retinal vein occlusion by injection of tissue
plasminogen activator into a retinal vein. American Journal of Ophthalmology
1998;126:142-144.
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