It's difficult to find anything bad to say about a movie featuring six adorable blind Tibetan children who are determined to climb a 23,000-foot peak just north of Mount Everest. The subjects are everything a documentarian might wish for: charming, emotive, and optimistic in spite of their tragic backstories: Tashi was abandoned by his family and forced to beg on the streets of Lhasa; Kyila's father and twin brothers are blind, too, and they're forced to keep house by themselves after her mother's death. Their sorrows are only compounded by Tibet's horrendous treatment of its blind — Buddhists there consider the malady a punishment for sins in previous lives. Luckily, Blindsight's director, Lucy Walker, does justice to the full range of these children's experiences, treating them as intellectual and emotional equals and refusing to patronize or exoticize them. The mountain climbing at the center of the film is, paradoxically, its least compelling aspect. Watching the group of Gore-Tex-clad figures stumble up a stony path left me with a few too many questions about the structure and purpose of the expedition: The kids seem dangerously unprepared for the altitude — it's unclear whether they trained for the climb — and their American guides come off as clueless and self-absorbed. Blindsight works best when it casts off the constraints of the adventure tale it wasn't meant to be and settles into a deft and humanistic treatment of blindness in Tibet.