The Optical Coherence Tomographic Profile of Leber Hereditary Optic Neuropathy.

The objective of this study was to describe the changes in the retinal ganglion cell complex (GCC) relative to the retinal nerve fibre layer (RNFL) over time in Leber hereditary optic neuropathy (LHON) patients. Average RNFL and GCC thickness was measured in seven patients in the early acute (123, 68.4 µm), late acute (113.5, 57.4 µm), and chronic (72.7, 50.8 µm) phases. Patients showed thinning of the GCC with RNFL swelling in the early acute phase. GCC thinning became severe within weeks and persisted. RNFL swelling normalised during the late acute phase with eventual thinning in the chronic phase. GCC changes appear at the commencement of visual loss and in some cases prior to vision loss. These findings define an optical coherence tomography (OCT) profile in LHON.

Distinguishing ischaemic optic neuropathy from optic neuritis by ganglion cell analysis.

PURPOSE: To determine whether a pattern of altitudinal ganglion cell loss, as detected and measured by optical coherence tomography (OCT), can be used to distinguish non-arteritic ischaemic optic neuropathy (NAION) from optic neuritis (ON) during the acute phase, and whether the rate or severity of ganglion cell loss differs between the two diseases. METHODS: We performed a retrospective, case-control study of 44 patients (50 eyes) with ON or NAION and 44 age-matched controls. Non-arteritic ischaemic optic neuropathy and ON patients had OCT at presentation and four consecutive follow-up visits. Controls had OCT at one point in time. The ganglion cell complex (GCC) was evaluated in the macula, and the retinal nerve fibre layer (RNFL) was evaluated in the peripapillary region. Ganglion cell complex thickness, RNFL thickness and GCC mean superior and inferior hemispheric difference were compared between NAION and ON patients at each time-point using unpaired t-tests and between disease and control subjects at first measurement using paired t-tests. RESULTS: Mean time from onset of symptoms to initial presentation was 10.7 ± 6.6 days in NAION and 11.7 ± 8.6 days in ON (p = 0.67). There was a significantly greater vertical hemispheric difference in GCC thickness in NAION patients than ON patients at all time-points (5.5-10.7 µm versus 3.1-3.6 µm, p = 0.01-0.049). Mean GCC thickness was significantly decreased at less than 2 weeks after onset in NAION compared to age-matched controls (72.1 µm versus 82.1 µm, p < 0.001), as well as in ON compared to age-matched controls (74.3 µm versus 84.5 µm, p < 0.001). Progression and severity of GCC and RNFL loss did not differ significantly between NAION and ON. CONCLUSION: A quantitative comparison of mean superior and inferior hemispheric GCC thickness with OCT may be used to distinguish NAION from ON.