To understand long sightedness, it first helps to understand how the eye works.
Long sightedness is a refractive error caused by an imperfection in the eye. The imperfection changes the way your eye focuses the light rays that pass into it. This can happen when:
- The eyeball is shorter than normal
- The cornea is less curved than normal
- The lens is thinner than normal
When any of these imperfections occur, it changes the focusing point of the eye so that light rays focus behind your retina, instead of onto it. This makes close-up objects look blurry. Distance objects still appear clear, because they don’t need as much focusing power, so they focus on your retina properly.
Hyperopia is believed to be an inherited condition, which means you’re more likely to suffer long sightedness if one of your parents has it. Hyperopia can develop in childhood, although symptoms are most common among adults.
Presbyopia is age-related long-sightedness.