The purpose of this study was to objectively analyse changes in the optic canal opening and conductibility of the optic nerve following allogenic hematopoietic stem cell transplantation (HSCT) in patients with osteopetrosis. 3D CT imaging was used along with visual electrophysiological technique to compare optic canal diameter in 20 patients (five male, 15 female aged 0.2-26 months) versus 22 controls (eight females, 14 male aged 3-40 months). Patient characteristics included good fixation in six, poor fixation in 14, strabismus in three, nystagmus in four, VII in three and optic atrophy in seven. Fourteen underwent HSCT; 11 gained hematopoietic reconstitution and three died of implant failure. Follow-up was from one year. From the fourth to fifth month after HSCT, the bone mineral density decreased gradually and medullary regions were visible in bones. Pre-treatment, the mean optic canal diameter was 1.65±0.54mm increasing to 2.72±0.66mm in 11 cases after one to two years. The authors conclude HSCT can relieve the progression of optic canal stenosis and control deterioration of visual function. Early treatment is associated with favourable outcomes.