Septo-optic dysplasia with unilateral optic nerve hypoplasia: case report

Septo-optic dysplasia (de Morsier syndrome) is a well-described entity that includes optic nerve hypoplasia and the absence of the septum pellucidum with or without pituitary abnormalities. We describe a case with unilateral optic nerve hypoplasia and absence of a septum pellucidum. A 6-year-old boy was referred to our clinic because of poor visual acuity. His best-corrected visual acuity was counting fingers at 15 cm in the right eye and 1.0 in the left eye. Extraocular muscle movements were normal, and exotropia of 30 prism diopters by Hirschberg test in the right eye was present. The pupils were equal and reactive to light with a mild Marcus Gunn pupillary response in the right eye. Perimetry revealed small visual fields in the superior quadrants of the right eye, while the left eye was normal. Ophthalmoscopic examination showed a small pale optic disc in the right eye; the optic disc of the left eye was normal. Magnetic resonance imaging showed the absence of the septum pellucidum. Endocrine studies revealed no evidence of pituitary insufficiency.