Researchers conducted an exploratory study to evaluate the efficacy and safety of frequent transcutaneous electrical stimulation (ES) for patients diagnosed with Leber hereditary optic neuropathy (LHON), particularly those carrying the mitochondrial mutation mt11778 G > A. This trial marks a significant effort to find effective treatments for this inherited condition, which leads to substantial vision loss, primarily affecting young adults.
Leber hereditary optic neuropathy is caused by genetic mutations resulting in the sudden apoptosis of retinal ganglion cells. Known for its debilitating impact on vision, LHON often results in visual acuity dropping to low levels, severely impacting patients' quality of life. Treatments to date have included idebenone, which has shown promise, and gene therapy. Yet, as LHON continues to pose challenges, researchers are investigating alternative therapeutic avenues.
Conducted at Kobe University, Japan, the study involved 14 patients aged 16 to 80, each diagnosed with LHON and confirmed to have the mt11778 G > A mutation. The trial took place over 12 weeks, with participants undergoing 30-minute sessions of ES applied every other day to one eye. The primary outcome measured was the variation in visual acuity, assessed using the logarithm of the minimal angle of resolution (LogMAR) before treatment and again at various intervals post-treatment.
Upon completing the study, results indicated no significant improvement across the board. The median LogMAR values recorded were 1.60 at baseline, 1.70 one week after the final treatment, and gradually improving to 1.50 at 8 weeks, showing fluctuations but no statistically significant changes. Secondary outcomes also reflected similar sentiments, with no marked advancements in visual fields or retinal thickness measurements.
Reporting on the findings, the researchers noted, "Frequent transcutaneous electrical stimulation did not improve visual acuity in patients with LHON carrying the mt11778 G > A mutation." They concluded with concern, noting, "There were no improvements in any secondary efficacy endpoints and no complications." This reflects on the persistent challenge of treating LHON effectively.
The observed trends suggest minimal natural variation rather than treatment-related improvement, indicating potential limitations of transcutaneous ES as an intervention for this condition. Interestingly, prior studies had hinted at possible benefits after less frequent ES, raising questions on the efficacy of treatment duration and frequency.
While some patients reported experiencing phosphenes, or temporary visual sensations elicited by stimulation, these responses did not correlate with improved visual function. One participant's notable improvement could have skewed earlier findings, yet the larger cohort indicated otherwise.
Despite the thorough methodology and ethical oversight from the Kobe University Clinical Research Ethical Committee, the study’s inability to demonstrate beneficial effects has raised both technical and clinical questions. Variability among disease onset durations among participants and possible differences between stimulation techniques could contribute to the overall findings.
Currently, with no improvement witnessed, the call for new approaches to LHON management becomes ever more pressing. Future research may benefit from exploring modified stimulation protocols or integrating complementary therapeutic strategies alongside ES.
Although the current study did not provide the hoped-for advances, the continued investigation highlights the persistence of the scientific community to seek effective treatments for challenging conditions like LHON.