What Are the Risk Factors for Cataract

What Are the Risk Factors for Cataract

What Are the Risk Factors for Cataract?

• Age. Aging accelerates free radical–induced oxidative damage to the lenses and alters the structure of alpha crystalline proteins, leading to opacity of the lenses and cataracts. This is the main reason cataracts tend to occur in old age.

• Diabetes. High blood glucose stimulates the activity of aldose reductase, an enzyme that converts glucose to sorbitol, resulting in an increased sorbitol concentration in the eyes. The accumulation of sorbitol increases intraocular pressure and induces damage to alpha crystalline proteins in the lenses, causing cataracts.

• Obesity. Fat tissues release leptin, a protein that informs the brain that the body has stored enough energy and can stop eating. Leptin resistance is common in obese individuals whose brains ignore the messages sent by leptin, bringing about the feeling of being hungry all the time, even right after having a meal. Leptin resistance triggers fat tissues to produce more leptin in obese people. The high amount of leptin enters the bloodstream and travels to the eyes, where leptin induces damage to alpha crystalline proteins in the lenses and causes cataracts.

• Alcohol. Moderate alcohol consumption may not hurt the eyes. However, heavy alcohol consumption can disrupt calcium homeostasis in the lenses. High concentrations of calcium in the lenses increase the risk of cataracts. In addition, excessive alcohol can also denature and alter the shapes of alpha crystalline proteins and lead to cataracts.

• Smoking. Cigarette smoke contains harmful chemicals that enter the bloodstream and travel to the eyes. These toxic chemicals induce a surge of free radical production, including superoxide anion radical and hydroxyl radical, and cause oxidative damage to alpha crystalline proteins in the lenses. Toxic chemicals from cigarette smoke can also deplete the zinc contents of the lenses. Zinc- dependent enzymes exhibit strong antioxidant properties. Insufficient zinc weakens the antioxidant capacity of the lenses, increasing the risk of cataracts.

• Sun exposure. People who do not wear sunglasses outdoors have a higher risk of cataracts. Ultraviolet rays from sun exposure induce a surge of free radical production in the lenses, which can cause oxidative damage to alpha crystalline proteins in them and lead to cataracts.

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