Amidst the plethora of ocular complications of
leprosy, involvement of the posterior segment or optic nerve is extremely rare. The mechanism of
optic neuritis in
leprosy is poorly understood. A 47 year-old man presented with a single lesion suggestive of mid-borderline (BB)
leprosy over left periorbital region; the histology showed
borderline lepromatous (BL)
leprosy with a BI of 3+. After initial improvement with WHO MDT-MB and
prednisolone (40 mg/d) he developed sudden and painless
diminished vision in the left eye, about 3 weeks later. His visual acuity was 6/9 in the left and 6/6 in the right eye, and there was left
optic disc edema,
hyperemia and blurred disc margins. Treatment with
prednisolone (60 mg/d) along with WHO MDT-MB continued. A month later he returned with painless
diminished vision in the other eye as well. Visual acuity was 6/6 in the right and 6/12 in the left eye, and there was right
optic disc edema and left optic disc
atrophy. CT of the head and MRI of the brain were normal. Inflammatory
edema of the orbital connective tissue or other surrounding structures, or direct infiltration of vasa nervosa with resultant vascular occlusion leading to
optic nerve ischemia, seems the most plausible explanation of optic nerve involvement in this case.