Millions of people around the world take medicine every day to control high blood pressure.
High blood pressure, also called hypertension, is often known as a “silent killer” because it can damage the heart, brain, and blood vessels without causing obvious symptoms.
Medicines that lower blood pressure have saved many lives by reducing the risk of heart attacks and strokes. One widely used group of medicines is called calcium channel blockers, often shortened to CCBs. These drugs work by relaxing and widening blood vessels so blood can flow more easily and the heart does not have to work as hard.
However, a new study has raised questions about whether these medicines might have an unexpected effect on eye health.
Researchers from Moorfields Eye Hospital and University College London in the United Kingdom found that people taking calcium channel blockers appeared to have a higher chance of developing glaucoma, a serious eye disease that can lead to permanent vision loss.
The researchers examined health information from more than 427,000 adults in the United Kingdom. More than 33,000 of these people were taking calcium channel blockers. The scientists carefully considered other factors that could influence the results, including age, smoking, and other medical conditions.
Even after taking these factors into account, they found that people who used calcium channel blockers were more likely to have glaucoma than people who were not using these medicines.
Interestingly, this connection was not found in people taking other kinds of blood pressure drugs. This finding caught the attention of researchers because it suggests there may be something unique about calcium channel blockers that affects the eyes.
Glaucoma is one of the leading causes of blindness around the world. The disease damages the optic nerve, which carries visual information from the eye to the brain. In many cases, glaucoma develops when pressure inside the eye becomes too high.
Over time, the damage can slowly reduce a person’s side vision and eventually affect central vision as well. One of the biggest challenges with glaucoma is that it usually develops very slowly and often causes no symptoms in its early stages. Many people do not realize anything is wrong until significant and permanent vision loss has already occurred.
One of the most surprising findings in this study was that the increased risk of glaucoma was also seen in people who had normal pressure inside their eyes.
This suggests that calcium channel blockers may affect the eyes through another pathway that scientists do not yet fully understand. Researchers believe more work is needed to discover exactly how these medicines could influence the optic nerve and eye health.
Because calcium channel blockers are commonly prescribed around the world, the findings could potentially affect many people. The study does not prove that these medicines directly cause glaucoma.
Instead, it shows an association, which means there appears to be a link between the medicine and the disease. More studies are needed before doctors can know for certain whether the medicines are responsible.
The researchers say these findings highlight the importance of regular eye examinations, especially for people who take blood pressure medicine and those who already have risk factors for glaucoma, such as older age or a family history of the disease.
Since glaucoma often develops without early warning signs, eye tests remain the best way to detect the condition before serious damage occurs.
People who are currently taking calcium channel blockers should not stop their medication because of this study. Untreated high blood pressure can lead to life-threatening complications.
Instead, patients should speak with their doctors if they have concerns. A doctor can help decide whether extra eye checks are needed or whether another type of blood pressure medicine may be more suitable.
Some of the researchers involved in the work have connections with pharmaceutical companies. This does not mean the results are incorrect, but experts say it is always important to consider such information when evaluating scientific studies.
The findings were published in the journal JAMA Ophthalmology and add to growing efforts to better understand how medicines used for one health problem may sometimes affect other parts of the body in unexpected ways.
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