Diagnostic value of magnetic resonance imaging and planimetric measurementof optic disc size in confirming optic nerve hypoplasia

Purpose: This study set out to evaluate magnetic resonance imaging (MRI) an d measurement of optic disc size as diagnostic tools for confirming the dia gnosis of optic nerve hypoplasia (ONH) in children with impaired growth. Me thods: MRI was performed to study the size of the intracranial visual pathw ays, and image analysis measurements of fundus photographs were performed t o determine the size of the optic disc. Results from these investigations w ere compared with those using the gold standard for diagnosis of ONH, which was the clinical eye examination (visual function, ophthalmoscopic signs, or both). Forty children (median age, 9 years; range, 3 to 19 years) with i mpaired growth were included in the study. Results:The prevalence of ONH am ong the children was 15%. MRI classification of the visual pathways had a h igher positive predictive value than image analysis measurement of the opti c disc size (1.0 vs 0.6). Conclusions: MRI is a good tool for confirming th e diagnosis of ONH and may thus facilitate early detection. On the other ha nd, a small optic disc per se is not a definite indicator of ONH but should encourage further investigation with MRI, especially if there is a clinica l suspicion of ONH.