Mountainfilm audiences have come to know the hyper-achieving Dr. Geoff Tabin, a world-class climber who has ascended the Seven Summits and who is best known for dramatically changing the rates of curable blindness in Nepal and Rwanda. Tabin and his team from the Moran Eye Center in Park City, Utah,  took their operation to South Sudan to work with John Dau (one of the original Lost Boys of Sudan whose remarkable story of survival was featured in the film God Grew Tired of Us 2007). Duk County, which was directed by Jordan Campbell, tells the story of this collaboration in which the sight of more than 200 people was restored. Unfortunately — and perhaps inevitably — this triumph is tainted by the ongoing conflict in South Sudan.