Defects of Vision And Their Correction

Defects in the eye happen due to many reasons. Due to growing age, the vision also decreases, and when the focal length alters, the vision also alters. 

When the eye loses its ability to adjust its focal length, problems appear like a person cannot see the image correctly (blurring of vision), unable to view nearby objects or far away objects. When the defect in the refractive index occurs, the person cannot see the objects comfortably and distinctly. If not taken timely care of, the eyes might completely lose the power of accommodation.

Refractive Defects of Vision

Some of the common defects of vision are:

(i) Myopia or near-sightedness

(ii) Hypermetropia or far-sightedness

Myopia or Near-Sightedness

Myopia is commonly known as near-sightedness. In this condition, the person can see the objects nearby but cannot see distant objects clearly. Faraway objects appear blurry, and a person will not be comfortable seeing them. Myopia condition takes place when the shape of the eyes leads the light rays to bend in a wrong way, focusing images in front of the retina rather than focusing on the retina.

Myopia is explained in the figure below.

Symptoms:

• Blurry vision.
• Difficulty in seeing while driving, particularly during night times.
• Headaches due to eyestrain.

Correction : When a concave lens of suitable power is used, it assists in focusing the image onto the retina.