Final answer:
The percentage of people in the United States who have cataracts by age 75 is 50%, with age being a predominant factor for the development of this condition. Statistics note that 60% of individuals aged 65 to 74 experience cataracts, emphasizing high prevalence in older age groups.
Step-by-step explanation:
The correct answer to the question of what percentage of people in the United States has a cataract by age 75 is C. 50%. According to the information provided, cataracts are a significant health issue that affects the clarity of the lens in the eye, leading to cloudiness and a potential loss of vision. As a person ages, the likelihood of developing cataracts increases, with statistics indicating that 60% of individuals between the ages of 65 and 74 are affected by this condition.
Vitamins A and C play a role in protecting the eye from the formation of cataracts, and sunglasses, especially those made of plastic that shield from UV rays, can help prevent the condition. When cataracts do form, treatment is typically straightforward and involves replacing the clouded lens with an artificial one. While cataract formation can be influenced by factors like exposure to UV-B rays, age remains the predominant factor contributing to its development.