Main causes of blindness worldwide

Blindness is the total or partial loss of luminous sensitivity.
The main causes of blindness worldwide are cataracts, glaucoma, age-related macular degeneration, diabetic retinopathy, trachoma and childhood eye conditions, such as those caused by vitamin A deficiency.
Age-related blindness and that due to uncontrolled diabetes are increasing worldwide, while infectious-cause blindness is decreasing thanks to public health measures.
According to the World Health Organization (WHO) the estimated number of people with visual disabilities is 253 million: 36 million with blindness and 217 million with moderate to severe visual impairment
90% of the world's blind are in developing countries, and African and Asian women account for two thirds of the total blind.
Three quarters of cases of blindness are preventable or treatable.
Among the causes of blindness we have those that can be reversed with medical or surgical treatment such as cataracts and irreversible ones, such as glaucoma.
Within the population with greater risks we have patients older than 50 years, who are more predisposed to suffer from visual disability due to chronic eye diseases and, at the other extreme, we have children under 15 years of age. It is estimated that the number of children with visual disabilities amounts to 19 million, of which 12 million suffer from it due to refractive errors. Approximately 1.4 million under 15s suffer irreversible blindness and need access to visual rehabilitation services to optimize their functioning and reduce disability.
As we mentioned, many of these causes can be determined with a complete ophthalmological examination performed by a medical professional. In the same, the ophthalmologist will not only determine if the patient needs corrective glasses, but will observe signs of possible asymptomatic alterations that could cause an irreversible loss of vision. It is also possible to detect secondary alterations to systemic diseases such as diabetes and hypertension and even signs of brain tumors.
According to WHO there are four levels of visual acuity (VA): normal vision, moderate visual impairment (VA <20/40), severe visual impairment (VA <20/200) and blindness (VA <20/400). Most blind people in developing countries live in rural areas, while most ophthalmological services and hospitals are in cities. 90% of blind people in developing countries can not work, which causes a reduction in social status and their ability to make decisions. The life expectancy is half or less if we compare with people without any type of visual disability.