Somewhere around the age of 40, most people’s eyes lose the ability to focus on close-up objects. This condition is called presbyopia. You may start holding reading material farther away, because it is blurry up close. Reading suddenly gives you eyestrain. You might wonder when manufacturers started

Myopia, or nearsightedness, means that your eyes can see close objects clearly but struggle to see things in the distance. Nearly 30 percent of Americans are nearsighted. This condition usually develops in children and teenagers, up to about the age of 20. A teacher or parent might notice a child squinting