Drinking a cup of hot tea at least once a day is useful for eyes and decreases risks of developing glaucoma, which is a serious eye condition. However, drinking decaffeinated and caffeinated coffee, decaffeinated tea, iced tea, and soft drinks does not seem to make any difference to glaucoma risk, according to a study.
Glaucoma is a group of diseases that can damage the eye’s optic nerve and result in vision loss and blindness. It is one of the main causes of blindness in the United States and worldwide. However, with early treatment, you can often protect your eyes against serious vision loss. Therefore, it is very important that it be diagnosed, according to the US National Eye Institute (NEI).
About 57.5 million people are currently affected by glaucoma, and the number is expected to increase to 65.5 million by 2020.
According to a new study published in the British Journal of Ophthalmology, glaucoma causes fluid pressure to build up inside the eye (intraocular pressure), damaging the optic nerve.
Although previous research suggests that caffeine can alter intraocular pressure, no study so far has compared the potential impact of decaffeinated and caffeinated drinks on glaucoma risk, the authors say in the study.
To get to their findings, the researchers examined data of the US nationally representative annual survey of around 10,000 people from the 2005-2006 National Health and Nutrition Examination Survey (NHANES).
That survey includes interviews, physical examinations, and blood samples designed to gauge the health and nutritional status of US adults and children. It also included eye tests for glaucoma.
According to the findings of the study, among the 1,678 participants who had full eye test results, including photos, 84 adults (5%) had developed the condition. They were asked how often and how much they had drank caffeinated and decaffeinated drinks, including soft drinks and iced tea, over the preceding 12 months, using a validated questionnaire.
The findings showed that, compared with those who didn’t drink hot tea every day, those who did had a lower glaucoma risk. It also showed that hot tea-drinkers were 74% less likely to have glaucoma, after taking account of potentially influential factors, such as diabetes and smoking.