A recent study from Denmark has broken new ground in understanding the underlying causes and health implications of branch retinal vein occlusion (BRVO), a serious eye disorder and common cause of vision loss that affects 13.9 million persons (primarily older adults) worldwide.
About Branch Retinal Vein Occlusion
As defined by PubMed Health, a retinal vein occlusion is a blockage [i.e., “occlusion”] of the small veins that carry blood away from the retina, the light-sensitive tissue that lines the inside surface of the eye. The retina converts incoming light into nerve signals and sends them to the brain, which interprets them as visual images.
Blockage of smaller, “branching,” veins (branch retinal vein occlusion or BRVO) in the retina often occurs when retinal arteries that have been thickened or hardened by atherosclerosis “cross over” and place pressure on a retinal vein. A branch retinal vein occlusion is sometimes referred to as “a stroke on the retina.”
The British Medical Journal
The Danish study, entitled Comorbidity in patients with branch retinal vein occlusion, was published on November 30, 2012, in the British Medical Journal (BMJ), an online, open-access, peer-reviewed journal published by the British Medical Journal Group. (Note: “Comorbidity” refers to the presence of one or more diseases or disorders in addition to a primary disease or disorder.)
The authors are Mette Bertelsen, Allan Linneberg, Thomas Rosenberg, Nynne Christoffersen, Henrik Vorum, Else Gade, and Michael Larsen, representing the following Danish institutions: Department of Ophthalmology, Glostrup Hospital; National Eye Clinic for the Visually Impaired, Kennedy Center; University of Copenhagen; Research Centre for Prevention and Health, Glostrup Hospital; Department of Ophthalmology, Aalborg University Hospital; and Department of Ophthalmology, Odense University Hospital.
The BMJ Study
An explanation of the study basics from BMJ:
The objectives of the study were to (a) evaluate comorbidity [i.e., the presence of one or more diseases or disorders] before and after the diagnosis of branch retinal vein occlusion to determine whether it is a consequence of [thickening arteries] and could serve as a diagnostic marker for other comorbidities and (b) to evaluate the risk factors for the development of such occlusion.
Of the 1,168 study subjects with a … diagnosis of branch retinal vein occlusion, most were aged 60-80 when they received the diagnosis. The 116,800 healthy control subjects were aged 40-70.
We found that the risk of developing branch retinal vein occlusion increased prominently with age, reaching its highest level in people aged 70-79. Before the diagnosis of branch retinal vein occlusion, people who would eventually develop this condition had higher overall comorbidity, and hypertension, diabetes, and peripheral artery disease were more prevalent than in the general population.
After receiving a diagnosis [of branch retinal vein occlusion], people without a history of these disorders were more likely than the general population to develop arterial hypertension, diabetes, congestive heart failure, and cerebrovascular disease.
Our study supports the theory that branch retinal vein occlusion is a marker of progressive cardiovascular disease that should be included in the risk assessment of patients for preventive intervention. General practitioners play an important role in the medical management of branch retinal vein occlusion through the identification and management of modifiable risk factors.
More About the Research
From Scientific Blogging: Science 2.0:
“Our new results indicate that branch retinal vein occlusion is caused by thickening of the arterial wall. This makes it crucial for doctors to treat patients diagnosed with the disease with medicine to lower blood pressure in order to prevent blood clots from forming in the heart and brain. Branch retinal vein occlusion is often a sign of increased risk of blood clots in other parts of the body,” explains [lead study author] Mette Bertelsen from the University of Copenhagen.
“To understand what is actually happening, it can be helpful to picture a garden hose that has been squeezed by a larger hose, cutting off the water supply. That is essentially what happens when a vein is compressed by a thickened artery. Clearly, the consequences can be serious,” explains Mette Bertelsen.
A Personal Story
VisionAware contributor Kaye Olson, lead author of the Coping with Vision Loss Study, describes her own struggle with branch retinal vein occlusion:
Similar to other adults with visual symptoms prior to a diagnosis, I said to my husband one morning, “I’m calling to have my eyes examined. I think I need a prescription change.” I had covered each of my eyes separately and the left eye was blurred, but I wasn’t yet concerned.
Initially, an ophthalmologist examined me at the clinic, but he told me I that I must see a retinal specialist within 24 hours. Following my eye exam with the retinal specialist, two statements propelled me into shock and disbelief: “You have a branch retinal vein occlusion (BRVO) with permanent complications, including vision loss,” and “There is no known treatment for you.” My physician compared it to a “stroke on the retina.” This occurred on March 26, 2002.
Even as an accomplished nurse practitioner, I had no knowledge about a BRVO and I wasn’t able to process how there couldn’t be any help for me in such modern times. I felt anger rising within me.
As I learned, the complications from my BRVO were severe and pervasive: retinal hemorrhaging, retinal ischemia (retinal cells dying from lack of oxygen), and a scarred macula, which permanently destroyed the central vision in my left eye.
Read Kaye’s story in its entirety to follow her personal journey through vision loss, including her discovery of support groups, coping strategies, and the restorative power of vision rehabilitation. VisionAware will continue to provide updates for this ongoing research as they become available.
Image source: BMC Ophthalmology, in accordance with the terms of Creative Commons Attribution 2.5 License.