Vision Problems Causes

Introduction to Vision Problem Causes

The human eye gives us the sense of sight and allows us to observe the adjacent world. We use our eyes in almost every activity, e.g. reading, working, watching television, writing a letter, driving a car, and in countless ways. Sight is the sense that is most valued as compared to the other sense organs.

The eye allows us to see various shapes, colors, and dimensions of objects in the world by processing the light.  The eye is able to sense bright light or dim light, and it is not possible to intellect objects when light is absent. I like to share this What Causes Static Electricity with you all through my article.

Problems of Vision & their Causes:

Following are the vision problems and their causes:

1) Myopia (Shortsightedness)

A person having this defect can see objects at short distance clearly but cannot see distant objects. The cause for this defect is

1. The eye ball becomes too long, so the rays coming from infinity get focussed in front of retina.

2. The focal length of the eye lens decreases. In this case also, the image is formed in front of retina when rays are coming from a distant object.

Myopia is corrected by placing a diverging lens (concave lens) of suitable focal length in front of the eye.

2) Hypermetropia (Long Sightedness)

A person with this defect can see distant objects distinctly but cannot see the near objects clearly. This defect is caused by

1) The eye ball gets too short so that image of objects is formed a little beyond the retina.

2) The focal length of eye lens increases. Because of this image is formed beyond the retina.

Hypermetropia is corrected by placing a converging lens (convex lens) of suitable focal length in front of the eye. Due to the converging lens, the rays get converged (focussed) on the retina. Please express your views of this topic Power Equation Physics by commenting on blog.

Defects of Vision & their Causes (continued)

3) Astigmatism:

In certain persons, the cornea of the eye is not absolutely spherical in shape but is distorted. It is also possible that it bulges out at certain points. Such a person suffers from astigmatism. If such a person looks at a wire gauge cross then its horizontal part will appear properly focused while the vertical one will appear blurred. So the person may be able to see in one plane but not in the other plane. Horizontal and vertical lines of a wire-gauge cannot be seen distinctly simultaneously. This defect is corrected by using appropriate cylindrical lens.

4) Presbyopia

This defect occurs due to aging. A person suffering from this defect can see neither nearby objects nor distant objects clearly/distinctly. This is because the power of accommodation of the eye decreases due to the gradual weakening of the capillary muscles and decreasing flexibility of the eye lens.

This defect can be corrected by using bi-focal lenses. Its lower part consists of a convex lens and is used for reading purposes, whereas the upper part consists of a concave lens and is used for seeing distant objects.

These days it is possible to correct these defects with the help of contact lenses or through LASIK-surgery.