How are Some people Nearsighted and Others Farsighted?!
Question:
How are Some people Nearsighted and Others Farsighted?
As people lose their vision, what makes some of them nearsighted and others farsighted. I can't understand how a person can be able to see an object that is far away more clearly than one that is up close to their face. How does your vision deteriorate like that?
Answers:
Well it’s really depending on what age group you are talking about. In younger people it’s not actually a deterioration of vision; it is just a natural change that happens especially with growth spurts.
When a person is farsighted (hyperopic) their eyeball is too short and the light coming into their eyes is focusing behind the retina. The light needs to focus on the retina in order for a person to be able to see clearly. When a person is nearsighted (myopic) their eyeball is too long and the light coming into their eyes comes into focus in front of the retina! Astigmatism is due the cornea or crystalline lens being shaped more cylindrical like a football then spherical like a baseball.
So basically people with different types of refractive errors (nearsighted, farsighted and astigmatism) are due to their eyes or parts of their eyes being sized/shaped differently.
As a person ages the crystalline lens in the eye that normally changes shape to focus on objects at near starts to loose its elasticity. As it looses its ability to flex we begin loose our ability to focus on objects at near (reading). This usually starts to become noticeable around age 40 and reading glasses are needed to read! This is a natural part of aging and has nothing to do with being nearsighted/farsighted!
Actual detoration of vision usually only happens in older persons with age related conditions such as macular degeneration or in medical illnesses!
Anyways hope this helps a bit :)