Geographical distribution of optic nerve hypoplasia and septo-optic dysplasia in Northwest England.

OBJECTIVE: To study the distribution of septo-optic dysplasia (SOD) and optic nerve hypoplasia (ONH) in the Greater Manchester and Lancashire (GM&L) region of Northwest England, and to analyze occurrence by location and over time. STUDY DESIGN: A population-based incidence study was undertaken for cases of SOD/ONH from GM&L. Standardized incidence ratio (SIR) for each district, relationships between SIRs and possible geographically varying risk factors, and spatial and space-time clustering were analyzed. RESULTS: Eighty-seven cases had a confirmed diagnosis of ONH/SOD giving an incidence of 10.9/100,000 per year in GM&L. SIRs ranged widely but were significantly elevated (lower confidence limit >100) in three districts: 167%, 192%, and 198%, respectively. All three were high population density, inner-city locations. SIRs were significantly correlated with higher rates of unemployment (r = 0.49, P = .01), dependent children in non-earning households (r = 0.47, P = .02), underage conceptions (r = 0.46, P = .02), and underage pregnancies (r = 0.44, P = .03). There was no evidence of spatial or space-time clustering. CONCLUSIONS: The incidence of ONH/SOD in GM&L was higher than that reported elsewhere. Cases were more common in areas that had higher unemployment and teenage pregnancy rates.

Optic nerve size evaluated by magnetic resonance imaging in children with optic nerve hypoplasia, multiple pituitary hormone deficiency, isolated growth hormone deficiency, and idiopathic short stature.

OBJECTIVE: To objectively define criteria for intracranial optic nerve (ON) size in ON hypoplasia (ONH) on magnetic resonance imaging (MRI) scans. STUDY DESIGN: Intracranial ON sizes from MRI were compared between 46 children with ONH diagnosed by ophthalmoscopy (group 1, isolated ONH, 8 children; and group 2, ONH associated with abnormalities of the hypothalamic-pituitary axis and septum pellucidum, 38 children) and children with multiple pituitary hormone deficiency (group 3, multiple pituitary hormone deficiency, 14 children), isolated growth hormone deficiency (group 4, isolated growth hormone deficiency, 15 children), and idiopathic short stature (group 5, idiopathic short stature, 10 children). Intracranial ON size was determined by the cross-sectional area, calculated as [pi x (1/2) height x (1/2) width]. RESULTS: Groups 1 and 2 had lower intracranial ON size than did groups 3, 4, and 5 (P < .001). No patients in groups 3 through 5 who had MRI after 12 months of age (when 95% adult size of ONs is attained) had ONs <2.9 mm 2 . Visual acuity correlated significantly with ON size (P < .01). CONCLUSIONS: Magnetic resonance imaging of the ONs with cross-sectional area <2.9 mm 2 in a short child more than 12 months of age, with or without hypothalamic-pituitary axis abnormalities, confirms the clinical diagnosis of ONH.