One of the main causes of blindness in sub saharan countries are cataracts. A group of french physicians has developed a surgical kit called “Phacokit” to treat at low-cost individuals suffering from cataract and help them recover their eyesight  [fr]:
Pour vaincre la cataracte, principale cause de cécité, notamment dans les pays pauvres, des médecins français ont mis au point un kit chirurgical qui permet d’opérer en 10 min, pour seulement 25 euros. Bill Gates s'est associé à cette découverte.
To recover from cataract, the leading cause of blindness in many sub Saharan countries, French doctors have developed a surgical kit that allows surgical operations to be performed in about 10 minutes, for only 25 euros. Bill Gates has provided support for this invention.
Here is a video that explains how the surgical kit works: