An 8-year-old boy presented with complaints of blurred vision in both eyes for 1 month. Recent frequent falling and inattention in the classroom were cited. Hearing impairment and frequent water drinking were also noted by his parents. The patient’s family history included the fact that he was adopted as a 10-day-old and his biological parents were known drug abusers. He was a premature baby with a gestational age of 35 weeks and a birth weight of 2300 g. Ophthalmoscopic examination revealed a best-corrected visual acuity of 6/60 in both eyes. Anterior segments were normal. Pupils were symmetric, and no relative afferent pupillary defect (RAPD) was found. Enlarged cupping was noted in both optic discs (Fig. 23.1). OCT showed decreased thickness of the naso-temporal peripapillary nerve fiber layer in both eyes (Fig. 23.2). A visual field examination revealed near total obscuration in both eyes (Fig. 23.3). A routine blood test including CBC, differential count, renal function, liver function, and electrolyte was normal. MRI revealed high signal lesions over the periventricular and deep white matter of bilateral parieto-occipital areas on T2-weighted and FLAIR images. There was also noted involvement of the splenium of the corpus callosum, bilateral lateral geniculate bodies, bilateral margins of the midbrain and pons, and bilateral middle cerebellar peduncles. There was marginal enhancement on T1-weighted images (Fig. 23.4), which was compatible with the MR findings of X-linked adrenoleukodystrophy.