Abstract
Purpose: :
To determine the effect of transcorneal electrical stimulation(TES) on the visual acuity of patients with traumatic optic neuropathy (TON).
Methods: :
Consecutive twenty-six eyes of 26 patients with TON treated by TES in our hospital between 2004 and 2007 and were followed-up at least 2 months after the treatment were studied. We classified the patients into three groups by the visual acuity before treatment. Severe group, log minimum angle of resolution (logMAR)≥2, n=7, moderate group, 1≤logMAR<2, n=10, and mild group, logMAR<1, n=9. TES (650-1000 µA, 20 Hz, 30 minutes) was applied using a contact lens-type stimulating electrode. Followed-up period was 2 to 21 months (average, 7.1 months) We measured the visual acuity, the threshold current to evoke phosphene in the peripheral visual field (Th1),and the current to evoke phosphene in the central visual field (Th2).
Results: :
The visual acuity improved equal or more than 0.3 logMAR units in 10 patients (1 in severe group. 6 in moderate group. 3 in mild group). The visual acuity did not worsen more than 0.3 logMAR units in any of the patients. Except for the severe group, visual acuity was significantly improved. (P=0.01 in moderate group and p=0.03 in mild group, Signed Rank Test). Th1 was significantly improved except for the severe group (P=0.01 in moderate group and p=0.03 in mild group). Threshhold of the central phosphene was significantly improved only in the mild group (p=0.016) . No side effect was observed except for a mild superficial keratopathy after TES.
Conclusions: :
The visual acuity and the threshold current to evoke phosphene improved after TES in some patients with TON without major complications. The treatment effect may not be expected in severely injured cases (logMAR≥2). These results suggest that TES could be considered as a new treatment for eyes with mild to moderate TON.
Keywords: neuro-ophthalmology: optic nerve • trauma • optic nerve