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Featured researches published by Gen Miura.


BMC Ophthalmology | 2016

Effects of cataracts on flicker electroretinograms recorded with RETeval™ system: new mydriasis-free ERG device

Gen Miura; Yosuke Nakamura; Eiju Sato; Shuichi Yamamoto

BackgroundThe purpose of this study was to evaluate the effects of cataracts on the flicker electroretinograms (ERGs) recorded with the RETeval™ system under mydriatic-free conditions.MethodsThis was a retrospective study of 82 eyes of 60 patients with cataracts and 52 eyes of 38 patients who were pseudophakic. Flicker ERGs were recorded with the RETeval™ system (LKC Technologies, Gaithersburg, MD) under mydriatic-free condition with skin electrodes. Flicker ERGs were elicited by white light delivered at a frequency of 28.3 Hz and intensity of 8 Td-s. The implicit times and amplitudes of the ERGs recorded from the Grade 2 cataract, Grade 3 cataract, and pseudophakic groups were compared.ResultsThe mean amplitude was significantly smaller in both cataract groups than the pseudophakic group (Grade 2 cataract vs pseudophakic group, P < 0.0001; Grade 3 cataract vs pseudophakic group, P < 0.0001; Grade 2 cataract vs Grade 3 cataract, P = 0.027).The mean implicit times was significantly longer in both cataract groups than the pseudophakic group (Grade 2 cataract vs pseudophakic group, P = 0.046; Grade 3 cataract vs pseudophakic group, P = 0.0004; Grade 2 cataract vs Grade 3 cataract, P = 0.0084).ConclusionsThe results indicate that the presence of Grade 2 or more cataracts will affect both the amplitude and the implicit time of the flicker ERGs. The presence of cataracts should be taken into consideration when interpreting the flicker ERG recorded with RETeval™.


Retina-the Journal of Retinal and Vitreous Diseases | 2007

Early postoperative macular morphology and functional outcomes after successful macular hole surgery.

Gen Miura; Satoshi Mizunoya; Miyuki Arai; Masanori Hayashi; Shuichi Yamamoto

Purpose: To investigate the relationship between early postoperative macular morphology and postoperative visual acuity in eyes that had undergone successful macular hole (MH) surgery. Methods: Pars plana vitrectomy and internal limiting membrane peeling were performed during surgery for idiopathic MHs on 25 eyes. The macular configuration was determined by optical coherence tomography, and best-corrected VA (BCVA) was measured postoperatively. Results: Eleven eyes had nearly normal foveal morphology (normal group) and 14 eyes had subretinal fluid or intraretinal cysts (abnormal group) at 1 month. Among the 14 eyes in the abnormal morphology group, normal foveal morphology was confirmed in 9 eyes 3 months and in the remaining 5 eyes 6 months after surgery. Mean BCVA improved significantly from the preoperative values in both groups 6 months after surgery. Conclusions: The morphology of the macular area was abnormal in more than one half of eyes that had successful MH surgery 1 month after surgery. However, by 6 months, all eyes had normal macular configuration, and BCVA was not significantly different in the two groups. We conclude that an abnormal morphologic appearance of the macular area in the early postoperative period does not predict the final visual outcome.


Case reports in ophthalmological medicine | 2013

Choroidal Metastasis of Non-Small Cell Lung Cancer That Responded to Gefitinib

Iwao Shimomura; Yuji Tada; Gen Miura; Toshio Suzuki; Takuma Matsumura; Kenji Tsushima; Jiro Terada; Ryota Kurimoto; Emiko Sakaida; Ikuo Sekine; Yuichi Takiguchi; Shuichi Yamamoto; Koichiro Tatsumi

A 52-year-old Japanese woman presented with optical symptoms, including left-sided myodesopsia, blurred vision, narrowed visual field, and diminished visual acuity. Ocular evaluation revealed a metastatic tumor in the choroid. Further examinations identified pulmonary adenocarcinoma as the primary tumor. Because an epidermal growth factor receptor gene (EGFR) mutation was detected in a biopsy specimen, gefitinib treatment was initiated. Dramatic responses were obtained in the primary tumor and metastatic foci. Optical symptoms improved and remained stable for 5 months during the treatment, until relapse. This report demonstrates that gefitinib is effective for choroidal metastasis of pulmonary adenocarcinoma harboring an EGFR mutation.


British Journal of Ophthalmology | 2015

Relationship between retinal microstructures and visual acuity after cataract surgery in patients with retinitis pigmentosa

Yosuke Nakamura; Yoshinori Mitamura; Akira Hagiwara; Ken Kumagai; Gen Miura; Takeshi Sugawara; Mariko Egawa; Shuichi Yamamoto

Aims To study the relationship between the retinal microstructures and the best-corrected visual acuity (BCVA) after cataract surgery in patients with retinitis pigmentosa (RP). Methods 58 eyes of 43 consecutive RP patients who underwent cataract surgery were studied. The BCVA was measured before and 3 months after the surgery. The appearance of the inner segment/outer segment (IS/OS) line of the photoreceptors in the optical coherence tomographic (OCT) images at the fovea was graded; Grade 1, IS/OS line not visible; Grade 2, IS/OS line abnormal or discontinuous; and Grade 3, IS/OS line normal. The central foveal thickness (CFT) and the length of the IS/OS line were measured in the spectral-domain OCT images. Results The postoperative BCVAs in logMAR units (Grade 1, 1.04±0.36; Grade 2, 0.33±0.16; Grade 3, 0.08±0.14) and the improvements in the BCVA in logMAR units (Grade 1, 0.22±0.28; Grade 2, 0.53±0.48; Grade 3, 0.54±0.35) were significantly different among Grade 1, 2 and 3 groups (p<0.0001, p=0.0378; respectively). A postoperative BCVA of <0.2 logMAR units was achieved in 0% in Grade 1, 20% in Grade 2 and 74% in Grade 3 (p<0.0001). There was a significant correlation between the postoperative BCVA and the length of the IS/OS line (r=−0.601 p<0.0001) or the CFT (r=−0.510, p<0.0001). Conclusions The presence of normal IS/OS line in the OCT images is associated with good visual recovery after cataract surgery in RP patients. The integrity of the IS/OS line may be important for predicting good postoperative BCVA.


Clinical Ophthalmology | 2018

Flicker electroretinograms of eyes with cataract recorded with RETeval system before and after mydriasis

Gen Miura; Takayuki Baba; Toshiyuki Oshitari; Shuichi Yamamoto

Purpose The aim of this study is to determine the effect of pupil size of eyes with cataracts on the flicker electroretinograms (ERGs) elicited and recorded with the RETeval system. Patients and methods Forty-one eyes of 41 patients (mean age, 76.5±7.3 years) that had grade 2 nuclear or cortical cataract without any other abnormalities were studied. Flicker ERGs were recorded before and after mydriatic drops instillation. The ERGs were elicited by the white light delivered at the frequency of 28.3 Hz and intensities of 2, 8, and 32 Td-s. The amplitudes and the implicit times of the flicker ERGs before and after mydriasis were compared. Results There were no significant differences between the amplitudes before and after mydriasis (P=0.35, 2 Td-s; P=0.31, 8 Td-s; P=0.50, 32 Td-s). There were also no significant differences between the implicit times before and after mydriasis (P=0.86, 2 Td-s; P=0.98, 8 Td-s; P=0.95, 32 Td-s). The mean amplitudes and implicit times of the nuclear and cortical cataracts groups before the mydriasis were also not significantly different from those after mydriasis for all stimulus intensities. Conclusion The lack of significant differences in the amplitudes and the implicit times of the flicker ERG of cataractous eyes before and after mydriasis indicated that the RETeval flicker ERGs in cataractous eyes is less affected by the pupil diameter. With our earlier study, it was assumed that the effect of cataracts on the RETeval flicker ERGs was due to the opacity of the crystalline lens, and the influence of the cataract would not be reduced or increased by mydriasis.


Documenta Ophthalmologica | 2015

Correlation between N2 amplitude of multifocal ERGs and retinal sensitivity and retinal nerve fiber layer thickness in glaucomatous eyes

Fusae Kato; Gen Miura; Suguru Shirato; Eiju Sato; Shuichi Yamamoto


Japanese Journal of Ophthalmology | 2006

Foveal Retinal Detachment and Retinoschisis Without Macular Hole Associated with Tilted Disc Syndrome

Gen Miura; Shuichi Yamamoto; Naoki Tojo; Satoshi Mizunoya


Japanese Journal of Ophthalmology | 2014

A case of ophthalmic artery occlusion following injection of hyaluronic acid into the glabellar area

Nonomura S; Toshiyuki Oshitari; Gen Miura; Chiba A; Shuichi Yamamoto


Retina-the Journal of Retinal and Vitreous Diseases | 2018

CORRELATIONS BETWEEN CHOROIDAL STRUCTURES AND VISUAL FUNCTIONS IN EYES WITH RETINITIS PIGMENTOSA

Mariko Egawa; Yoshinori Mitamura; Masanori Niki; Hiroki Sano; Gen Miura; Akihiro Chiba; Shuichi Yamamoto; Shozo Sonoda; Taiji Sakamoto


BMC Neurology | 2018

Case of convulsive seizure developing during electroretinographic recordings: a case report

Yuko Hayashi; Gen Miura; Akiyuki Uzawa; Takayuki Baba; Shuichi Yamamoto

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Mariko Egawa

University of Tokushima

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