Optic nerve hypoplasia in patients with septo optic dysplasia (SOD) and isolated optic nerve hypoplasia (ONH)
E Stone, J Kirk, H Willshaw & P Goode
Introduction: Optic nerve hypoplasia (ONH) can be bilateral or unilateral. It may be found either as an isolated finding or as part of other conditions such as septo-optic dysplasia (SOD), a variable triad of ONH, midline brain defects, and hypopituitarism. We have analysed data on patients with ONH within our regional cohort.
Patients and methods: Ophthalmology and endocrinology case records from 136 patients with SOD (56) or ONH (79) were analysed. ONH was diagnosed on clinical examination, electrodiagnostic assessment and ultrasound examination of ON diameters. Endocrine dysfunction was categorised as multiple (MPHD) or isolated pituitary hormone deficiency. High resolution MRI images were also obtained
Results: Of all patients with ONH, 44/123 (36%) had SOD; 35/81 (43%) had bilateral ONH. There was increased M:F ratio in bilateral ONH 1.9:1 compared to 0.5:1 in unilateral ONH. No significant difference in perinatal history between uni- and bilateral ONH in patients with SOD was found. SOD patients with bilateral ONH are more likely to have MPHD than those with unilateral ONH. Nearly 50% of patients with bilateral ONH with SOD had GH, ACTH and TSH deficiency compared 22% of patients with unilateral ONH.7/35 (20%) of bilateral ONH SOD had all 3 components of triad, including MPHD, were blind or had severe visual impairment.
Conclusions: Bilateral ONH itself is not predictive of SOD, although patients with bilateral ONH and SOD are more likely to be severely affected.