Introduction: Frontonasal dysplasia is a rare condition of congenital structure malformations of the midface. Ophthalmologic abnormalities have been estimated to occur in 87% of cases of frontonasal dysplasia.
Case report: We report a case of type I frontonsal dysplasia in a 15-year old boy after the correction of severe hypertelorism, median nasal cleft w~ith a broad nasal root and associated decompensated intermittent exotropia with overaction. of the inferior oblique muscles and V pattern. He underwent bilateral lateral rectus recessions of 6.0 mm for intermittent exotropia when he was six years old. The correction of hypertelorism was performed with orbital rotation surgery when he was thirteen years old. For some time after strabismus surgery, the ocular alignment improved, but it deteriorated gradually. The ocular alignment improved after the hipertelorismus correction; however, intermittent exotropia deteriorated gradually again six to seven months later. On the last ophthalmologic examination, he had the ocular alignment on the level of small angle exotropia and associated hypertropia and occasionally even.small angle esotropiaat near. There was bilateral overelevation in addiction and V pattern, which remained unchanged after extensive facial bones surgical procedures.
Conclusion: The high incidence of ocular abnormalities, particularly exodeviations, indicates that the early assessment by an ophthalmologist should be a part of the initial evaluation of patients with frontonasal dysplasia to detect treatable visual or ocular problems.