Dr Yeoh went on a charitable cataract screening and surgical expedition to the Amazon forest in central Brazil where the isolated Indian tribes live far from civilisation and modern medical care. In the two week trip, together with the non-governmental organisation called Forest Doctors, they visited two tribes in the forest to do eye screening and examination followed by cataract surgery on those needing it in the nearby town of Canarana, Mato Grosso. You can read more about it in Dr Yeoh’s blog : https://thenaturaltraveller.net/2018/06/19/cataract-camp-for-xingu-indians-brazil/