Abstract
Purpose: :
Nonarteritic anterior ischemic optic neuropathy (NAION) and traumatic optic neropathy (TON) are optic nerve diseases accompanied by a sudden decrease of vision but there is no established treatment that can restore the vision. We have shown that the survival of retinal ganglion cells (RGCs) after axotomy of the optic nerve was significantly increased if transcorneal electrical stimulation (TES) with a contact lens electrode was applied just after the axotomy in adult rats (Morimoto,et al, IOVS, 2005). Based on this animal experiment, we investigated the efficacy and safety of TES as a method of improving and preserving the function of the optic nerve fibers in eyes with NAION and TON after obtaining the informed consent in full compliance with the institutional review board.
Methods: :
TES (600–800 µA, 20 Hz, 30 minutes) was applied once to 8 eyes, 3 with NAION and 5 with TON, of 8 consecutive patients at Osaka University Hospital using a contact lens–type (Burian–Allen) of stimulating electrode. The interval between the visual loss and the time of the TES treatment was 4 to 24 months (median 6 months) in the NAION group and 3 weeks to 11 months (median 4 weeks) in the TON group.The primary outcome measure was the change of visual acuity at 1 to 3 months after TES. An improvement of visual acuity was defined as a change of ≥0.3 log minimum angle of resolution (log MAR) units. The side effects of TES were also investigated.The procedures used conformed to the tenets of the Declaration of Helsinki.
Results: :
The visual acuity improved in 2 patients with NAION, and 4 patients with TON after the TES application. The visual acuity did not worsen in any of the eyes. Only a mild superficial punctuate keratopathy was observed in all eyes just after TES, which was healed by the next day.
Conclusions: :
The visual acuity can be improved after TES without major complications in some patients with NAION or TON in the chronic stage. These results suggest that TES can be considered as a new treatment for eyes with optic neuropathy.
Keywords: neuro-ophthalmology: optic nerve • neuroprotection • electrophysiology: clinical