Presbyopia, or age-related farsightedness, is caused by changes in proteins in lens fiber cells. It is considered the most common eye condition, affecting the lives of around 1.8 billion people around the globe up to the year 2015. As one ages, one gradually loses their accommodative ability in the eye because of a decrease in the concentration of alpha-crystallin in human lenses, rendering them unable to focus on objects nearby. The disease is a hindrance to day-to-day activities, especially for individuals from the ages of 50 and above.

Our team proposes a solution to this widespread eye disease. In addition to changes in lens proteins, oxidative stress induced by a decreased blood supply in the vital organ which damages retinal cells is also considered a major cause. And daily intake of antioxidants, specifically bioflavonoids, prevents the hardening of the lens. Quercetin is recognized for its antioxidant, anti-inflammatory, and anti-carcinogenic properties. We gain most of our intake of flavonoids from food like citrus fruits, onions, and green tea, because our bodies don’t produce flavonoids. The project genetically engineers Bifidobacterium, a probiotic ubiquitous in the human gastrointestinal tract, to produce quercetin within our bodies. Quercetin then travels from the gut to the eyes, where it may come into effect to inhibit the accumulation of lipids and thus inhibit lens aldol reductase, forming a self-existing flavonoid production and delivery system. Therefore, in this study, the engineered quercetin will become a part of our gut bacteria production; delivered by the nervous system, quercetin will effectively travel to our eye sites and prevent the loss of elasticity in the lens.