But, in fact, the pain and irritation it causes can significantly affect a person’s quality of life.
In DES, also known as keratoconjunctivitis sicca, the eye does not produce enough quality tears to stay lubricated and nourished.
Tears are essential for clear vision and for eye health. When the eye does not produce enough of them, the result is visual disturbance and even damage to the surface of the eye. DES is a common, often chronic, eye disease that is especially prevalent among older adults.
Research has shown that inflammation — both systemic and local — plays an important role in the development of DES. Many chronic inflammatory diseases, including diabetes mellitus, rheumatoid arthritis, allergic diseases, and irritable bowel syndrome, have been associated with DES.
Interestingly, many of these diseases are also associated with low levels of 25-hydroxyvitamin D (25(OH)D) or inadequate sunlight exposure. So researchers decided to investigate whether vitamin D levels and sunlight exposure are directly associated with DES risk.
In a cross-sectional data analysis that included 17,542 non-institutionalised adults who participated in the Korean National Health and Nutrition Examination Survey 2010–2012, researchers looked at information collected about sunlight exposure, as well as serum 25(OH)D and zinc levels.
After adjusting for confounding variables — age, sex, obesity, diabetes, rheumatoid arthritis, depression, thyroid disorder, atopic dermatitis, prior eye surgery, exercise and occupation — the researchers found that low serum vitamin D levels and insufficient sunlight exposure were both risk factors for DES.
This study suggests that for people with DES and those at risk (including those suffering from chronic inflammatory diseases) may benefit by increasing sunlight exposure and/or supplementing with vitamin D.