What makes our vision go blury (so we need glasses)??

Question

What makes our vision go blury (so we need glasses)??

Answer 1

When you become nearsighted (can see up close but not far away), it is because either the eyeball itself is too long or the cornea is overly curved, making the that image you see only in focus in front of the retina (the T.V. screen for your brain basically).

When you become farsighted (can see far away, but not up close), it is because the image is in focus behind the retina.  This happens if the eyeball becomes smaller or cornea isn't curved enough.

When you become presbyopic (the condition that makes you need reading glasses as you get older) it is because the cornea starts to stiffen with age and makes it hard to focus on near objects.

If you are diagnosed with astigmatism, it means that the light rays that make up the image you see don't focus on only one spot, making your vision blurry at any distance. This happens because the eye is shaped more like a football than a sphere.

We believe genetics (and also age) causes these changes in our eyes. Wearing someone else's glasses or sitting too close to the T.V. won't do anything to make your eyes worse.

By wearing glasses or contacts (which you can for each of these conditions), it makes the whole image focused right on the retina.

If you need to know something else, feel free to E-mail me.

Here are  good links as well.

http://www.allaboutvision.com/conditions...

http://www.allaboutvision.com/conditions...

http://www.allaboutvision.com/conditions...

http://www.allaboutvision.com/conditions...

Answer 2

the focal point for the light rays in the eye. i personally have an astigmatism so the focal point is oddly arranged because of the outer shape of my eye.

Answer 3

i'm not sure about this, so someone correct me if i'm wrong.

i THINK there is a muscle in your eye that like hardens or isn't flexible and that causes the blurryness.

Answer 4

Refractive errors ( A refractive error, or refraction error, is an error in the focusing of light by the eye and a frequent reason for reduced visual acuity.)

are usually caused by 3 things, or a combination of these  things.

Refractive errors are frequently categorized as spherical errors and cylindrical errors:

Spherical errors (People with eyes that have curves like a basketball is round) happen  when the optical power of the eye is either too large or too small to focus light on the retina. People with refraction errors usually have blurry vision.

When the optics are too powerful for the length of the eyeball (this can arise from a cornea with too much curvature or an eyeball that is too long), one has myopia (Near sightedness.)

When the optics are too weak for the length of the eyeball (this can arise from a cornea with not enough curvature or an eyeball that is too short), one has hyperopia (Far sightedness.)



Cylindrical errors (A person would have an eye shape like a football, instead of a basketball) occur when the optical power of the eye is too powerful or too weak across one meridian of the optics. It is as if the overall lens tends towards a cylindrical shape along that meridian. People with this refraction error see contours of a particular orientation as blurred, but see contours with orientations at right angles as clear. When one has a cylindrical error, one has astigmatism.

Refractive errors are thought to happen because of a combination of genetic and environmental factors. Trauma or other specific ocular disorders such as keratoconus may induce  refractive errors.