Abstract
Purpose :
To assess the changes in retinal ganglion cell (RGC) and visual pathways function in patients with Leber’s hereditary optic neuropathy (LHON) during one year of follow-up.
Methods :
Twenty-two patients (mean age: 36.3±9.3 years) carrying a LHON mutation and with the onset of visual symptoms no less than 2 years, providing 44 LHON eyes, were enrolled. In LHON eyes, Pattern Electroretinograms (PERGs) and Visual Evoked Potentials (VEPs) were recorded in response to 60-minute (60’) and 15-minute (15’) checkerboard stimuli at baseline and after 6 and 12 months of follow-up. At baseline, the 95 % confidence limit of test-retest variability (CL, mean plus 2 standard deviation for VEP P100 Implicit Times- IT- and mean minus 2 standard deviation for PERG P50-N95 Amplitudes) were calculated. After 6 and 12 months of follow-up, the values of PERG and VEP parameters were considered as “unmodified” when the differences with respect to baseline were within the 95% CL; as “worsened”, when the increase in VEP P100 IT and the reduction in PERG P50-N95 Amplitudes exceeded the 95% CL; as “improved” if the shortening in VEP P100 IT and the increase in PERG P50-N95 Amplitudes exceeded the 95% CL.
Results :
Compared to baseline values, the majority of LHON eyes showed unmodified PERG and VEP values: 28/44 (63.64 %) for PERG P50-N95 Amplitudes after 12 months and 30/44 (68.18%) for VEP 60’ and 15’ P100 IT after 6 and 12 months (“unmodified” LHON eyes). The great worsening for PERG and VEP values was observed on 13/44 (27.27%) LHON eyes at 12 months of follow-up (“worsened” LHON eyes). An improvement of VEP 60’ and 15’ P100 IT was found only on 2/44 (4.55%) LHON eyes after 6 months and of PERG P50-N95 Amplitudes only on 4/44 (9.33%) LHON eyes after 12 months (“improved” LHON eyes). On average, in LHON eyes, after 6 and 12 months, not significant (ANOVA vs Baseline, p>0.05) changes in VEP 60’ and 15’ P100 IT and PERG P50-N95 Amplitude values were found with respect to baseline.
Conclusions :
In LHON, during a 12 months period of follow-up, RGC function and neural conduction along the visual pathways were substantially unmodified in the majority of studied eyes. Nevertheless, in the remaining LHON eyes it is possible to observe either a worsening (the prevalence of not “unmodified” LHON eyes) and an improvement (in an exiguous number of not “unmodified” LHON eyes) of RCG and visual pathways function.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.