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Nearsightedness vs. Farsightedness

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The eye is a precious gift we cannot take for granted. It is the window we use to see the wonders of the world. It dictates how we move, perceive and interact in our daily life.

How does the eye work?

The reflected light of the world enters through the crystal transparency of the cornea, aqueous humor, lens and vitreous humor. These eye components then project the reflected light onto the photoreceptor of the retina, whose impulses, converge on the optic nerve and then to the brain. Once the light reaches the brain, it can then be transmitted into imagery with built-in meaning.

The eye in today’s world

In today’s world, the eyes surface constantly protect itself and adjust to changing conditions such as less sleep, contact lens, dust, computer glare, air conditioning, heat, pollution. Every blink helps our eyes natural defense system. The tear film retains moisture and maintains visual accuracy. The miraculous biology of our eyes inspires us to develop ways we can to protect and sustain comfort for these remarkable structures. After all, for all the wonders our eyes provide throughout our lives, we owe them our attention and ongoing care.

Mechanism of a normal human eye

The eye of the human is said to be normal if the eye has a near point of 25 cm and a far point of infinity. The near point is defined as the closest distance the eye can focus objects clearly, while the far point is the farthest point an eye can be seen clearly.

When a person with a healthy eye is viewing an object that is very far away, i.e., an object at infinity (object distance is infinity), the rays of light coming to the eye form the object will be parallel concerning the principal axis.

When the rays of light enter the cornea and lens, refraction of light takes place, and all these rays of light will essentially converge into a single point called the focal point found on the retina.

The main type of conditions that affect the human eye:

While there are many different conditions that can affect our vision, there are two that stand out amongst the crowds. Nearsightedness and farsightedness are by far the most common vision problems that almost everyone has heard about.

Nearsightedness (myopia)

Nearsightedness is eye condition, which the far point is not infinite, but some finite distance.

This means the eye cannot focus objects that are found very far away; a person with this kind of eye views an object far away, the object becomes blurry. An eyeball that is too long usually causes it. In such a case, the image is formed onto a point in front of the retina.

To correct this type of conditions convex lenses are used.

Farsightedness (hyperopia)

Farsightedness is a condition of the eye, which the near point is higher than 25 cm.

This means that the object viewed will appear blurred. It is usually caused by an eyeball that is too short. In such a case, the image is focused on a point that is found at the back of the retina.

This condition is corrected by using concave lenses.

Should you feel that you are dealing with nearsightedness or farsightedness, you should visit an eye care center to get a proper eye exam. Do not “manage” any eye condition, it is safer to see an optician at soon as possible.

Written by Joey Postma

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