At least 2.2 billion people around the world have some form of visual impairment, even though many cases, practically half, could be prevented or treated simply, with glasses or surgery. Avoidable visual impairment continues to be, today, a major public health challenge in numerous countries. In Sahrawi refugee camps, in Mozambique, or in Bolivia, the difficulties in accessing specialized health services in vulnerable communities prevent prevention and early diagnosis and, therefore, the indication of treatments.