Ganglion Cell Complex Thickness and Visual Function in Chronic Leber Hereditary Optic Neuropathy

Area of Science:

• Ophthalmology
• Neuroscience
• Genetics

Background:

• Leber hereditary optic neuropathy (LHON) is a mitochondrial disease causing acute or subacute vision loss.
• Macular ganglion cell complex (GCC) thickness, assessed by optical coherence tomography (OCT), is a key indicator of retinal nerve fiber layer damage.
• Automated OCT segmentation can introduce errors in GCC thickness measurements, potentially impacting disease monitoring in chronic LHON.

Purpose of the Study:

• To evaluate the correlation between manually corrected macular ganglion cell complex (GCC) thickness and visual function in chronic Leber hereditary optic neuropathy (LHON).
• To assess the impact of automated segmentation errors on GCC thickness measurements in LHON patients.

Main Methods:

• Twenty-six chronic LHON subjects were enrolled, with 60% receiving idebenone or CoQ10 treatment.
• Optical coherence tomography (OCT) scans were analyzed using the Iowa Reference Algorithm, with manual correction of segmentation in nine macular sectors.
• Visual function was assessed using best-corrected visual acuity (BCVA) and visual field tests (Esterman and custom 30° tests).

Main Results:

• Automated segmentation overestimated GCC thickness by 16–30 µm across macular sectors compared to manual correction (P < 0.001).
• Corrected GCC thickness in all sectors significantly correlated with BCVA, mean defect, and Esterman score.
• The external temporal sector showed the strongest correlation with visual function parameters (e.g., BCVA: r = 0.604, P < 0.001).
• Treated subjects had better BCVA (P = 0.017), but no significant differences in GCC thickness or visual field scores were observed between treated and untreated groups.

Conclusions:

• Manually corrected GCC thickness measurements correlate well with visual function in chronic LHON.
• Segmentation errors in automated OCT analysis can be misleading for monitoring LHON progression and treatment efficacy.
• Precise GCC measurements, achieved through careful OCT segmentation evaluation, are essential for monitoring structural changes in LHON.