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VISUAL DISTURBANCES AND FOCUSING IMPAIRMENT - Coggle Diagram
VISUAL DISTURBANCES AND FOCUSING IMPAIRMENT
When the eye works properly is said emmetrope.
There are the most common defects of the eye
Myopia
Hypermetropia
Astigmatism
Presbyopia
Daltonism
Myopia:
The eye refractive power is too strong.
The eyeball is too long.
The light rays are focused in front of the retina.
Concave corrective lenses are needed to focus on distant objects.
Hypermetropia:
The eye refractive power is too weak.
The eyeball is too short.
The light rays are focused behind the retina.
Convex corretive lenses are needed to get good focus on close objects.
Astigmatism:
The cornea doesn't curve corretly.
The person cannot focus on the main meridians.
We can use the special lens.
Presbyopia:
Is commen in old age.
Is caused by the gradual loss of the crystalline lens elasticity.
It reduced the ability to focus the eye on near objects.
Daltonism:
Means colour blidness for some colours. (doesn't see some colours.)
VOCABULARY
Affect:
influenzare
Blindness:
cecitÃ