As a child, Joshua James Amberson was diagnosed with pseudoxanthoma elasticum, a rare genetic condition that may eventually lead to sightlessness. “In my own mild way,” his book opens, “I like to obsess,” and what follows is a relentlessly curious series of detours through oft-ignored aspects of vision and vision loss. Deftly weaving together such disparate subjects as Bette Davis’s career, the daily challenges of eye contact, and his own decade-long saga of periodic eye injections, Amberson digs deeply into the physical and existential consequences of living with such uncertainty. Staring Contest is wise, generous, and—given the subject matter—surprisingly funny.