Pedrotti E, et al. - In this trial, the authors determined the prevalence of obstructive sleep apnea (OSA) in subjects having keratoconus (KCN). They also evaluated the relationship between the severity of KCN and OSA. As measured by overnight home sleep apnea testing, among patients with KCN, OSA was seen to be 10 to 20 times more prevalent than the rate reported for the general population. They found that the rate lied between the prevalence estimated from sleep study data of self-reported diagnosis of OSA and the risk of developing OSA as determined by the Berlin Questionnaire.