Blindness is a complete or partial lost of ones sight, a condition where the physiological function of the eyes is impaired

Causes of blindness and visual impairment

In spite of the progress made in surgical techniques in many countries during the last ten years,

cataract (47.9%) remains the leading cause of visual impairment in all areas of the world, except for developed countries.

Other main causes of visual impairment are

glaucoma (12.3%),

age-related macular degeneration (AMD) (8.7%),

corneal opacities (5.1%),

diabetic retinopathy (4.8%),

trachoma (3.6%), and onchocerciasis (0.8%).

here also are listed life style that might be damaging to our sights and they include;

excessive use of mobile phone and chatting,

this kills your retina, can also cause long or shot visions

insomia, sleeplessness at the night,

excessive watching of movies, zee world and co

lack of checkup by the optometrics

not washing the eye when washing the face in the morning,

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Source: http://generalhealthinfo.com/2017/12/16/things-might-make-loose-sight/