title: 25% cluster.
authors.affiliation: Department of Neurology, Boston University School of Medicine, Boston University Medical Center, MA, USA Michael.Perloff@bmc.org.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Perloff
authors.affiliation: Department of Neurology, Boston University School of Medicine, Boston University Medical Center, MA, USA.
authors.forename: Sok
authors.initials: S
authors.lastname: Lee
mesh_terms: D003027:Cluster Headache / Q000150:complications* / Q000175:diagnosis*; D006801:Humans; D007499:Iris Diseases / Q000175:diagnosis* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010859:Pigmentation Disorders / Q000175:diagnosis* / Q000209:etiology*; D013997:Time Factors