One local doctor in Japan completed a study that shows that Japanese men with high blood pressure had a higher chance of having an impairment in seeing colors.
High blood pressure could damage certain parts of the eye, ultimately leading to vision loss, according to Dr. Saadia Rashid, an ophthalmologist from Montefiore Medical Center in New York, who was not involved in the study. “It will be great if acquired color vision impairment can be a harbinger of future hypertension-related complications, however it is premature to state that,” Rashid told Reuters. The study was small and is the first to make the connection between blood pressure and impaired vision, so more research will be needed for more conclusive evidence.
It was Dr. Takuhei Shoji of Saitama Medical University in Japan who decided to examine the link between eye disease and cardiovascular risk factors, as well as lifestyle habits. The study reviewed 872 men in the Japanese Self Defense Force in Kyoto, between the ages of 20 and 60; they were given two tests to see how well they could see and determine various colors. In one test, 130 failed, and 31 failed the other. The research team examined the participants’ medical records, weight, cholesterol, blood sugar levels, and any eye diseases. They discovered the higher the participants' blood pressure was, the greater the chances of having impaired color vision.
The study is limited because it didn't give researchers a chance to look at vision changes or blood pressure levels across time. In addition, the link between impaired vision and high blood pressure is a correlation, not necessarily causation. But the researchers believe that “[t]he data are useful and important for further investigations of many of these associations,” they wrote.
“Future research is needed to popularize this idea, and perhaps come up with simpler ways of checking color vision, on modalities such as home smartphones and devices as a home screening tool,” Rashid said. “We have to wait for the research to catch up.”
Source: Shoji T, Sato H, Chihara E, Sakurai Y. “Are Middle-Age Blood Pressure Levels Related to Color Vision Impairment? The Okubo Color Study.” American Journal of Hypertension, 2014.