Top: Fundal pictures show diffuse optic nerve pallor in a 14-year-old male (case no. 6 in the table) with methylmalonic acidemia of neonatal onset, complicated with end-stage renal failure necessitating transplant. Final visual acuity was light perception in the right eye and 6/48 in the left. Bottom: Bilateral optic atrophy in an 11-year-old female (case no. 12 in the table) with propionic acidemia diagnosed days after birth. Marked optic cupping is observed, found to have developed 24 months after acute bilateral loss of vision during a metabolic crisis. Initial cup/disc ratio was 0.2 for either eye. Visual acuity was hand movements and 6/60 for right and left eyes, respectively. Both cases had electrodiagnostics, showing absent evoked potentials and decreased dark-adapted responses on electroretinography. RNFL, retinal nerve fibre layer.