INTRODUCTION TO THE OPHTHALMIC LITERATURE OF AN UNUSUAL CAUSE OF PAPILLEDEMA AND SUBSEQUENT OPTIC ATROPHY: X-linked hypophosphatemic rickets (XLH).Case report of a 3-year-old female presenting with papilledema resulting from craniosynostosis secondary to XLH.Early intervention with craniofacial surgery prevented the development of optic atrophy.Children with XLH should be screened for ophthalmic evidence of elevated intracranial pressure to aid early intervention and prevention of permanent loss of vision