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Biomedical subjects

Hiroshi Shimojyo

Publications and source records attributed to Hiroshi Shimojyo.

4 recordsLinked to original sources
PubMed2006

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

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

Adult↗
PubMed2006

Wavefront analysis of eye with monocular diplopia and cortical cataract.

PURPOSE: To determine whether higher-order aberrations can explain the monocular diplopia reported by a patient. DESIGN: Observational case report. METHODS: A patient complaining of monocular diplopia was examined with the Hartmann-Shack aberrometer to determine if the higher-order wavefront aberrations could account for the diplopia. The patient had a mild cortical cataract, and measurements were made before and after lensectomy. In addition, the retinal image was simulated using Zernike polynomials. RESULTS: Spherical aberration (0.20 microm for 4-mm pupil) and secondary astigmatism (-0.12 microm) were increased in the eye. The simulated retinal image had a double configuration that was approximately the same as the subjective image reported by the patient. After cataract surgery, the diplopia disappeared, and the spherical aberrations and secondary astigmatism were considerably decreased. CONCLUSIONS: The monocular diplopia probably stemmed from the combined effects of spherical aberration and secondary astigmatism caused by the cortical cataract.

Adult↗
PubMed2002

Effect of simultaneous oblique muscle surgery in foveal translocation by 360 degrees retinotomy.

PURPOSE: To assess the effect of simultaneous oblique muscle surgery during foveal translocation surgery with 360 degrees retinotomy in patients with neovascular maculopathy. METHODS: Foveal translocation with 360 degrees retinotomy was performed on 31 eyes of 31 patients with neovascular maculopathy (21 with age-related macular degeneration 9 with myopic neovascular maculopathy, and 1 with idiopathic neovascular maculopathy). All eyes had simultaneous torsional muscle surgery with recession of the superior oblique muscle and tucking of the inferior oblique muscle. Visual acuity, binocular vision, and degree of cyclotorsion were assessed pre- and postoperatively. The angles of retinal and global rotation, distance of foveal shift, and surgical complications were also investigated. RESULTS: With a mean postoperative follow-up of 10.0 months, vision improved (>0.2 log MAR units) in 13 eyes, was unchanged in 9 eyes, and worsened (>0.2 log MAR units) in 9 eyes. Ten of 31 eyes (32%) had a final visual acuity of 20/50 or better. Eleven patients had binocular fusion, 13 patients showed suppression, and 7 patients developed diplopia that was managed by spectacles with prisms or by secondary muscle surgery. The mean retinal and global rotations were 30.3 degrees and 23.7 degrees, respectively. The average size of the choroidal neovascular membrane was 1.3 disc diameters (DD), while the average shift of the fovea was 1.5 DD. After the primary surgery, six eyes developed retinal detachment, two eyes macular hole, and three eyes proliferative vitreoretinopathy. These complications were successfully managed by additional surgery. CONCLUSION: Foveal translocation with 360 degrees retinotomy is effective in restoring vision in 40% of patients with neovascular maculopathy. Simultaneous oblique muscle surgery was effective in rotating the globe by about 20 degrees, corresponding to to a foveal shift of 1.5 DD. While the development of torsional diplopia is generally prevented by simultaneous oblique muscle surgery, the relatively high incidence of surgical complications with this procedure should be taken into account.

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