AbstractPurpose To characterize the visual phenotype of asymptomatic Leber’s hereditary optic neuropathy (LHON) associated with mtDNA 11778G>A mutation in carriers from the same family.Methods Computerized psychophysical assessment methods (CCT ‐ Cambridge Colour Test and CSF ‐ Metropsis Contrast Sensitivity Function Test) were used to evaluate visual function in a population of 17 subjects of two generations of the family mentioned above (mean age ± SD = 27.94±12.97 years; mean visual acuity ± SD = 1.25±0.11) which was compared with an age‐matched control group. This evaluation was completed with electrophysiological assessment (Multifocal ERG, Pattern ERG and Pattern VEP). Stratus‐OCT3 was used for structural evaluation. Statistical analysis at a significance level of p<0.05 was performed using ANOVA, when applicable (otherwise Mann‐Whitney was used).Results CCT showed evidence for damage of all cone populations (0.0001<p<0.006), implying concomitant damage of parvo/ koniocellular pathways. No significant damage occurred in the achromatic contrast sensitivity across the spatial frequency channels studied, suggesting a relatively preservation of achromatic pathways. PERG results were normal, while mfERG (testing preganglionic pathways) showed a decrease in central ring amplitudes (p=0.006), corroborating central cone damage. Retinal thickness was decreased in the inner rings (R1:p=0.012; R2:p=0.04), irrespective of changes in macular nerve fiber layer thickness. Cortical responses (VEP) were delayed (60':p=0.002 / 15’:p=0.02) with normal amplitudes.Conclusion Our results suggest that, besides the classical concept of ganglion cell dysfunction, damage to outer retinal circuits could also contribute to subclinical impairment in LHON carriers.