Abstract
Purpose:
To determine whether the improvement of the visual acuity in eyes with traumatic optic neuropathy (TON) is associated with the current intensity of transcorneal electrical stimulation (TES).
Methods:
This was a prospective, randomized, partially blinded, clinical trial of 27 patients at the Osaka University Hospital. All patients had TES (10 ms, biphasic pulses, 20 Hz) for 30 min once a month in their TON eyes for 6 months. The patients were randomly divided into two groups; 1.0 mA (n = 17) or 0.3 mA (n = 9). The primary outcome measurement was the change in the best-corrected visual acuity (BCVA) at 3 and 6 months after the start of the TES treatment. An improvement in visual acuity was defined as a change of ≥0.2 logarithm of the minimum angle of resolution (logMAR) units. The changes in the BCVA in the two groups were compared.
Results:
The improvement in the BCVA in the 0.3 mA group was 0.10 ± 0.085 logMAR units and that in the 1.0 mA group was 0.11 ± 0.049 logMAR units at 3 month (P=0.73). The improvement in the BCVA at 6 month in the 0.3 mA treatment group was 0.04 ± 0.085 logMAR units which was significantly less than that in the 1.0 mA group of 0.26 ± 0.049 (P=0.039) logMAR units. The improvement of the BCVA was found in 22.2% of the patients in the 0.3 mA group and 23.5% of the patients in the 1.0 mA group at 3 months, and 22.2% in the 0.3 MA group and 47.1% in the 1.0 mA group at 6 months. The differences were not statistically significant (P=0.94 and P=0.21, respectively).
Conclusions:
TES at 1.0 mA can improve the VA in patients with TON more effectively than at 0.3 mA. These results indicate that there is probably an optimal neuroprotective current intensity of TES for eyes with TON. These value will provide a guideline for the use of TES in patients with TON. Further studies with larger sample sizes and longer duration are needed to confirm the findings and to define the optimal stimulation parameters.