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Graefes Arch Clin Exp Ophthalmol. 2006 Oct;244(10):1283-92. Epub 2006 Mar 21.

Evaluation of residual retinal function by pupillary constrictions and phosphenes using transcorneal electrical stimulation in patients with retinal degeneration.

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  • 1Department of Applied Visual Science, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.



To evaluate inner-retinal function by pupillary constrictions and phosphenes evoked by transcorneal electrical stimulation (TES) in patients with hereditary retinal degeneration.


Consecutive 20 eyes of 20 patients (16 with retinitis pigmentosa (RP); and four with cone-rod dystrophy (CRD)) whose visual acuity was equal to or worse than 20/2000 at Osaka University Hospital and eight eyes of eight healthy subjects were enrolled. TES was performed on with a contact lens stimulating electrode. The electrically evoked pupillary response (EEPR) was recorded by a pupillometer, and the phosphenes by the subjective responses. Three electrical current thresholds were determined: T1, threshold current for initial phosphene; T2, threshold for eliciting a phosphene extending into the central field; and P, threshold for a relative pupillary constriction > or = 3%. The EEPR and phosphene thresholds were compared with the visual acuity or the visual field.


All T1, T2 and P were significantly higher in patients than in normals (Mann-Whitney, P<0.001). Both T1 and T2 were not correlated with visual acuity but depended on the area and location of the residual visual field. T1 and T2 in RP eyes with a EEPR was significantly lower than that in RP eyes without an EEPR. During TES, all subjects and patients had no pain, and no complications except for a slight corneal superficial punctuate keratopathy.


The safety and the efficacy of TES to estimate the residual inner-retinal function in patients with retinal degeneration indicate that TES can be used as one of the most important test to select candidates for retinal prostheses.

[PubMed - indexed for MEDLINE]
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