Abstract
Purpose::
In ischemic optic neuropathy (ION) or in traumatic optic neuropathy (TON), the visual decrease is often severe and there is no established treatment that can restore the vision. Recently we have developed a new treatment using transcorneal electrical stimulation (TES) and have applied it to patients with these diseases (Fujikado, et al 2006). The effect of TES treatment has been subjectively evaluated by visual acuity, central flicker fusion frequency, and visual field. In this study, we investigated if the effect can be evaluated objectively by pupillary reflex.
Methods::
Consecutive patients with ION and TON who visited the Osaka University Hospital between March in 2003 and April in 2006 who has been followed up for more than half a year after TES treatment was investigated. Bilateral cases were excluded. The number of patients was 22 in ION and 7 in TON. The visual acuity ranged from hand motion to 1.0 (20/20) (average: 0.05(20/400)) in the affected eye and was equal or better than 20/20 in the fellow eye. An infrared pupillometer, the IRISCORDER® (Hamamatsu Photonics K.K., Japan), was used to measure the pupillary responses evoked by light stimulation (LS) or by TES (1000±200µA). In TES examination, electrical current was applied to the retina through Burian-Allen contact lens electrodes (current; 600-1000µA, frequency; 20Hz, duration; 10msec). We defined an index of pupillary reflex (IPR) by dividing the relative amplitude of indirect pupillary reflex of the affected eye by that of direct pupillary reflex of the fellow eye. IPR was plotted against the logMAR value of the affected eye in both LS and TES.
Results::
In both ION and TON, the IPR correlated with logMAR value either in LS or TES. (LS on ION: r = - 0.65, P<0.0001, TES on ION: r= - 0.44, P<0.0001; LS on TON: r = - 0.50, P<0.01, TES on TON: r = - 0.38, P<0.01).
Conclusions::
In ION and TON, IPR of LS or TES significantly correlated with logMAR. Therefore, we concluded that IPR can be an objective parameter to evaluate the effect of TES treatment on optic neuropathy.Keyword (Ischemic Optic Neuropathy, Traumatic Optic Neuropathy, Pupillary Reflex , Flash light, Trans-corneal Electrical Stimulation )
Keywords: neuro-ophthalmology: optic nerve • trauma • ischemia