Is Second Eye Involvement in Leber's Hereditary Optic Neuropathy Due to Retro-Chiasmal Spread of Apoptosis?

Late-Onset Leber's Hereditary Optic Neuropathy with Concurrent Retinal Detachment and Retrobulbar Visual Pathway Involvement

We report a case of late-onset Leber's hereditary optic neuropathy (LHON) with concurrent retinal detachment, mild retinal pigment epithelial changes, cataract and hyperintensity on fluid-attenuated inversion recovery magnetic resonance imaging affecting the entire retrobulbar visual pathway. We also documented that progression of the visual field defect correlated with retinal nerve fibre layer and ganglion cell layer-inner plexiform layer changes on optical coherence tomography. Our case provides further understanding of LHON as a disorder of the entire pre-geniculate pathways and also highlights that detailed history taking in addition to recognition of typical sequential optic disc appearance and visual field characteristics at different stages of LHON remain critical even in this era of modern imaging, autoimmune biomarkers and genetic testing.

Leber Hereditary Optic Neuropathy Associated with Bilateral Macular Holes

Leber hereditary optic neuropathy (LHON) causes visual loss, predominantly in healthy young men. We recently examined a patient who previously had bilateral macular holes and subsequently developed LHON at 74 years of age. Although his central scotomas were initially attributed to the macular holes, his visual acuity declined following an initial improvement after operative closure of the macular holes; thus, other diagnoses, including LHON, were considered. Furthermore, macular optical coherence tomography (OCT) images remained unchanged in this time. A mitochondrial genetic analysis identified a 11778G→A mutation. From this case, we propose that LHON remains in the differential diagnosis even in older patients, as has previously been reported.

Raised intraocular pressure as a potential risk factor for visual loss in Leber Hereditary Optic Neuropathy

Leber Hereditary Optic Neuropathy (LHON) is an important cause of inherited mitochondrial blindness among young adults. The majority of patients carry one of three mitochondrial DNA (mtDNA) point mutations: m.3460G>A, m.11778G>A and m.14484T>C, all of which affect critical complex I subunits of the mitochondrial respiratory chain. LHON is characterised by marked incomplete penetrance, clearly implying that the mtDNA mutation is insufficient on its own to trigger retinal ganglion cell dysfunction and visual loss. In this case series of three affected patients harbouring the m.11778G>A mutation, we provide evidence suggesting that raised intraocular pressure could be a risk factor triggering visual loss in at-risk LHON carriers.

Initial temporal field defect in Leber hereditary optic neuropathy

PURPOSE

To determine the site of the initial field defect in patients with Leber hereditary optic neuropathy (LHON).

METHODS

We studied nine eyes of nine consecutive LHON patients with the 11778 mitochondrial DNA mutation who had no visual loss (four eyes) or only minimal visual loss (five eyes). When unilateral visual loss was observed, Humphrey field analysis (HFA) (HFA 30-2 program and sometimes the HFA 10-2 program) was immediately and repeatedly performed on the better eye.

RESULTS

For the 12 centralmost points in the visual field, a loss of sensitivity (P<0.02) was initially found in the upper temporal field of nine eyes and in the lower temporal field of three eyes. These results indicate that it was possible to detect the initial site of sensitivity loss in the centralmost temporal test points in all nine cases. The HFA 10-2 program confirmed the sensitivity loss in the temporal field in two cases.

CONCLUSIONS

The centralmost temporal visual field appears to be the most susceptible site in eyes of LHON patients. This suggests that the most susceptible cells during the early stages of LHON are the retinal ganglion cells located in the corresponding region of the retina.