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4 Problems with hearing and sight

The ear is one of the most sensitive parts of the human body. Some diseases GLOSSARY
that can affect it are: deafness: hearing loss

Otitis Vertigo Ménière’s disease
It is inflammation of the Vertigo is a feeling of It is a disease of the
ear, usually due to an movement or spinning inner ear, of unknown
infection. It is separated that is often known as cause. It can cause
into external otitis and dizziness. It is due to a severe dizziness,
otitis media. Otitis problem in the part of hearing loss, and a
media is the most the inner ear that pressure sensation or
common. controls balance. ear pain. It is a common
cause of deafness.

Diseases that affect the eye are classified into refractory and
non-refractory diseases.
Refractory diseases affect accommodation; the image is not focused
correctly on the retina and vision becomes blurred or distorted. The most
common refractory diseases are:

REFRACTORY VISION DISEASES

Myopia Astigmatism Farsightedness

Blurred distant Deformed image Defocused close
vision view

It is due to an excessive length of It occurs when the cornea has an It is due to a short length of the
the eyeball, which causes objects to irregular curvature. This causes eyeball, which causes objects to be
be drawn in front of the retina. blurred and distorted vision. drawn behind the retina. People
Short-sighted individuals clearly see The irregular structure of the cornea with farsightedness can focus on
nearby objects, while distant ones is usually genetic, or can be caused distant objects, but nearby objects
blur. To correct this, glasses with after surgery. It is corrected using look blurry.
divergent lenses are used. cylindrical lenses.

The most common non-refractory diseases are cataracts, colour blindness,
glaucoma, and conjunctivitis.

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