Millions of people around the world take medicine every day to control high blood pressure. High blood pressure often has no obvious symptoms, but over time it can damage the heart, brain, kidneys, and blood vessels.
Treating it is one of the best ways to lower the risk of heart attack and stroke. One group of medicines commonly used for this purpose is called calcium channel blockers, often shortened to CCBs. These medicines help relax blood vessels so blood can flow more easily, lowering blood pressure.
A new study from the United Kingdom has found that these widely used medicines may also be linked to a higher risk of glaucoma, a serious eye disease that can slowly steal eyesight if it is not found and treated early.
The research was led by Dr. Alan Kastner and his team at Moorfields Eye Hospital and University College London. The findings were published in JAMA Ophthalmology.
The researchers examined health information from more than 427,000 adults. Around 33,000 of them were taking calcium channel blockers for high blood pressure.
After taking into account factors such as age, lifestyle, and other medical conditions, the team found that people using CCBs were more likely to have glaucoma than people who were not taking these medicines. The same increase in risk was not seen in people using other common blood pressure medicines.
One of the most surprising discoveries was that the higher glaucoma risk did not appear to be caused by increased pressure inside the eye. Eye pressure is usually considered one of the main causes of glaucoma. This finding suggests that calcium channel blockers may affect the eyes through another pathway that scientists do not yet fully understand.
Glaucoma is often called the “silent thief of sight” because it usually develops slowly without warning signs. Most people notice no pain or changes in vision during the early stages. As the disease progresses, it damages the optic nerve, which carries visual information from the eye to the brain.
Once the optic nerve is damaged, the lost vision cannot be restored. This is why regular eye examinations are so important, especially for older adults and people with known risk factors.
The study also found that people taking calcium channel blockers showed changes in the eye that are commonly seen in the early stages of glaucoma. These changes were detected during eye imaging tests, even in some people who had not yet developed vision problems. This suggests that eye scans may help identify warning signs before noticeable sight loss occurs.
Even though the findings are important, they do not prove that calcium channel blockers directly cause glaucoma. This was an observational study, which means it found a link but could not show cause and effect.
More research is needed to understand why the connection exists. Scientists believe the medicines may change blood flow to the optic nerve, but other explanations are also possible.
People who are taking calcium channel blockers should not stop their medicine without talking to their doctor. High blood pressure is a serious condition that needs proper treatment. For most people, the benefits of controlling blood pressure are still very important.
However, patients who have a family history of glaucoma or other risk factors, including diabetes, older age, or African, Asian, or Hispanic background, may wish to discuss regular eye examinations with their healthcare provider.
The researchers also noted that some members of the research team have connections with pharmaceutical companies. However, the study did not show that these relationships affected the results.
This research highlights that medicines can sometimes have effects on parts of the body that were not expected. It also shows why scientists continue to study medicines even after they have been used safely for many years.
Learning more about both the benefits and the possible risks of treatments can help doctors and patients make better decisions and protect long-term health.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and natural coconut sugar could help reduce blood pressure and artery stiffness.
For more information about blood pressure, please see recent studies about How to eat your way to healthy blood pressure and results showing that Modified traditional Chinese cuisine can lower blood pressure.
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