Leber's Optic Atrophy-DTI

18 yr old student has developed sudden visual loss in one eye with history of maternal uncles having been blind in youth. Clinical exam and eye evaluation suggested hereditary optic atrophy . MRI showed symmetrical thinning of the optic nerves in introorbital regions consistent with lebers variety of hereditary optic atrophy. Case by Dr MGK Murthy and Mr Hari Om.

Teaching points

• It is mitochondrial neurodegenerative disease acquired through the mutated genes. Females pass it on and affected males do not
• It is bilateral with simultaneous(25%) or sequential (75%)involvement of both eyes
• Starts in young age with males(24 years mean) affected earlier than females(31years)
• Sometimes coexists with Multiple sclerosis when it is called Hardings syndrome
• LHON plus is referred to the Lebers Atophy with other diseases like movement disorders and cardiac arrhythmias
• Pathology is limited to retinal ganglion cell layer with reduced glutamate transportation

Optic nerve has various components and MRI can delineate them all

1. Intraocular component 1mm
2. Intraorbital 25 mm
3. Intracanalicular 5mm
4.  Intracranial 10 mm

Visual pathway
Optic nerves- optic chiasma- optic tracts- lateral geniculate bodies in the pulvinar –superior colliculi of brainstem-visual cortex of occipital lobes . This could be effectively depicted on Diffusion Tractography