The Laryngeal Mask Airway ProSeal™ (LMA-ProSeal™; Laryngeal Mask Company Limited) is a reusable supraglottic airway device developed to enhance supraglottic airway protection and extend the benefits of the classic LMA (Laryngeal Mask Airway) to greater number of patients. Added features include an additional drain tube to channel fluid away from the airway and a tighter seal against the glottic opening with no increase in mucosal pressure. Clinicians have extended the use of the LMA-ProSeal™ inside and outside the operating theatre including use for difficult airway management and airway rescue. However, even these new devices have their limitations. We report an unforeseen acute airway obstruction caused by LMA-ProSeal™ malfunction during ophthalmic surgery. The cuff of the device was deformed with herniation to one side upon insufflation of the balloon.