Researchers reviewed 12 studies that used genetic information to understand what causes retinal vein occlusion (RVO)—a serious eye condition that can lead to vision loss. By studying genetic data, scientists can identify which health factors truly cause RVO rather than just being associated with it. The review found that eye pressure, high blood pressure, weight gain, and blood sugar problems are the strongest genetic risk factors for RVO. This research suggests that controlling blood pressure, maintaining a healthy weight, and managing blood sugar levels may be the most important ways to prevent this eye condition.

The Quick Take

  • What they studied: Scientists wanted to figure out which health conditions actually cause retinal vein occlusion (when a blood vessel in the eye gets blocked) by looking at genetic studies.
  • Who participated: The review looked at 12 different genetic studies, all of which studied people of European ancestry. These studies used genetic information from thousands of people to understand disease causes.
  • Key finding: The strongest genetic risk factors for retinal vein blockage were: high eye pressure (53% increased risk), high blood pressure (58% increased risk), excess weight (94% increased risk), and high blood sugar (5 times higher risk for fasting glucose levels).
  • What it means for you: If you want to protect your eyes from this serious condition, focusing on controlling blood pressure, maintaining a healthy weight, and keeping blood sugar levels normal may be your best prevention strategies. However, this research is based on genetic patterns and doesn’t prove these factors will prevent the condition in every person.

The Research Details

This was a systematic review, which means researchers searched four major medical databases for all published studies that used a special genetic research method called Mendelian randomization. This method uses genetic information to figure out which health factors actually cause diseases, rather than just being linked to them. The researchers found 12 studies that met their criteria, all conducted in people of European ancestry.

Mendelian randomization works like a natural experiment. Instead of randomly assigning people to different treatments (which is hard to do for long-term health factors), scientists use genetic variations that people are born with as “proxies” or stand-ins for lifelong exposure to certain risk factors. This helps them determine cause-and-effect relationships that would be difficult to prove otherwise.

Because the studies used different methods and measured different things, the researchers couldn’t combine all the results into one big analysis. Instead, they reviewed each study individually and rated the strength of evidence for each risk factor as robust (very strong), probable (fairly strong), suggestive (weak), insufficient (not enough evidence), or non-evaluable (couldn’t assess).

This research approach is important because it helps separate true causes from mere associations. For example, people with retinal vein blockages might also have high cholesterol, but that doesn’t necessarily mean high cholesterol causes the blockage. By using genetic information, scientists can identify which factors are actually responsible for the disease, which helps doctors and patients focus prevention efforts on the most important targets.

The studies reviewed were all peer-reviewed research published in reputable journals, which is a good sign of quality. However, all 12 studies focused on people of European ancestry, so the findings may not apply equally to other ethnic groups. The researchers were transparent about this limitation and called for more diverse studies. The fact that multiple independent studies showed similar results for some risk factors (like high blood pressure and excess weight) makes those findings more reliable.

What the Results Show

The strongest and most consistent findings involved eye-related factors. Higher eye pressure increased the risk of retinal vein blockage by 53%, and genetic liability to glaucoma (a related eye disease) increased risk by 31%. These were the most robustly supported findings across the studies reviewed.

For cardiovascular (heart and blood vessel) factors, high blood pressure showed strong evidence of increasing retinal vein blockage risk by 58%. Cholesterol levels showed mixed results—higher LDL cholesterol (the “bad” kind) and total cholesterol increased risk, but the evidence wasn’t as consistent across studies.

Metabolic factors (related to how your body processes energy) showed some of the strongest associations. Fasting blood sugar levels showed a dramatic 5-fold increase in risk, and two-hour glucose levels (measured after eating) showed a 3-fold increase. Type 2 diabetes liability showed a 2.8-fold increased risk. Body weight measures were also strongly associated: higher BMI increased risk by 94%, and larger waist circumference increased risk by 140%.

Other factors showed more mixed or preliminary evidence. Blood clotting factors showed probable to robust associations, but vitamin D evidence was insufficient to draw conclusions. Gut bacteria showed preliminary evidence but needs more research.

The review found that blood clotting and platelet function (cells that help blood clot) showed probable to robust evidence of association with retinal vein blockage risk. This suggests that how easily blood clots may play a role in this condition. Vitamin D levels did not have enough evidence to determine if they affect risk. Certain types of gut bacteria showed preliminary evidence of association, but this finding is very new and needs confirmation from more studies.

These genetic findings largely confirm what doctors have observed in clinical practice—that high blood pressure, diabetes, obesity, and eye pressure problems are associated with retinal vein blockages. However, this research goes further by using genetic evidence to suggest these factors actually cause the condition rather than just occurring together by chance. The strong associations with blood sugar and weight are particularly notable and suggest metabolic health may be even more important than previously thought.

The biggest limitation is that all 12 studies focused on people of European ancestry, so we don’t know if these findings apply equally to people of African, Asian, Hispanic, or other ancestries. Genetic risk factors can vary between populations. Additionally, the studies measured slightly different things and used different methods, which made it impossible to combine all the results into one overall analysis. Some risk factors (like vitamin D) had too few studies to draw firm conclusions. Finally, genetic associations don’t tell us exactly how these factors cause the disease—just that they do. The studies also couldn’t measure some important factors like smoking or alcohol use as thoroughly.

The Bottom Line

Based on this genetic evidence, the most important prevention strategies appear to be: (1) controlling blood pressure through medication and lifestyle changes if needed—strong evidence; (2) maintaining a healthy weight through diet and exercise—strong evidence; (3) managing blood sugar levels and preventing or controlling diabetes—strong evidence; (4) having regular eye exams to monitor eye pressure and glaucoma risk—strong evidence. These recommendations have high confidence based on the genetic evidence reviewed.

Anyone concerned about eye health should pay attention to these findings, especially people with family histories of retinal vein blockages, high blood pressure, diabetes, or obesity. People with glaucoma or elevated eye pressure should be particularly vigilant. However, these findings are based on genetic patterns and may not apply equally to all ethnic groups. People of non-European ancestry should discuss these findings with their eye doctor to understand how they apply to them personally.

Improvements in blood pressure control and blood sugar management may reduce risk relatively quickly (within weeks to months), while weight loss benefits typically appear over months to years. Eye pressure changes from treatment may show effects within weeks. However, this research shows genetic associations, not guaranteed prevention—some people with excellent control of these factors may still develop retinal vein blockages, while others with less control may not.

Want to Apply This Research?

  • Track weekly averages of blood pressure readings, fasting blood sugar levels (if diabetic), and weight. Set target ranges: blood pressure below 130/80 mmHg, fasting glucose 80-130 mg/dL (if diabetic), and BMI in the healthy range for your height.
  • Use the app to set reminders for blood pressure medication, schedule regular eye exams every 6-12 months, log daily steps toward a 150-minute weekly exercise goal, and track meals to support weight management and blood sugar control.
  • Create a monthly dashboard showing trends in blood pressure, weight, and blood sugar (if applicable). Set alerts if readings consistently exceed targets. Share quarterly summaries with your doctor to adjust prevention strategies as needed. Track eye exam dates and any changes in vision or eye pressure measurements.

This research identifies genetic associations with retinal vein occlusion but does not prove that controlling these factors will prevent the condition in every person. The findings are based on studies of people of European ancestry and may not apply equally to other ethnic groups. This information is for educational purposes and should not replace professional medical advice. If you have concerns about your eye health or risk factors for retinal vein occlusion, please consult with your eye doctor or healthcare provider. Do not make changes to your medications or treatment plans without discussing them with your doctor first.