Double ring sign in optic nerve head hypoplasia.

Double ring sign of optic nerve head is a characteristic fundus finding in cases with optic nerve head hypoplasia (ONH).[1] ONH has been associated with congenital intracranial anomalies like thinning of corpus callosum, absence of septum pellucidum and pituitary ectopia.[23] A 6-year-old male child without any significant perinatal or endocrinological history, presented with vision OD 6/6 and OS 6/18, normal anterior segments and unilateral ONH in OS [Fig. 1a]. Ratio of disc-macula distance to disc-diameter i.e., DM/DD was 3.2 (more than 3 is suggestive of ONH[4]). The MRI revealed hypoplasia of left optic nerve [Fig. 1b] and thinning of corpus callosum [Fig. 1c]. ‘De Morsier's syndrome’ was ruled out due to normal endocrinological function and normal septum pellucidum. ONH has an incidence of 1/2287 live births, and 2.4/100,000 in children less than 19-year-old.[5] The differential diagnosis of ONH include optic nerve atrophy, optic nerve coloboma, morning glory anomaly, tilted disc syndrome, and glaucoma.

Figure 1

Fundus picture of left eye (a) depicting characteristic double ring sign (black arrows) of optic nerve head, coronal section of MRI (b) showing mild hypoplasia of left optic nerve (white arrow), sagittal section of MRI (c) showing thinning of distal body (white triangle) and splenium (white arrow) of corpus callosum

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