Ryo Obata

Dr. Ryo Obata


Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2009 in Ophthalmology
Verified
Journal Article
Closed access
TUTakashi Ueta
Takashi Ueta
RORyo Obata
Ryo Obata
YIYuji Inoue
Yuji Inoue
AIAya Iriyama
Aya Iriyama
HTHidenori Takahashi
Hidenori Takahashi
YYYasuo Yanagi
Yasuo Yanagi

1 June 2013 in Retina
Verified
Journal Article
Closed access
RORyo Obata
Ryo Obata
HTHidenori Takahashi
Hidenori Takahashi
TUTakashi Ueta
Takashi Ueta
KYKentaro Yuda
Kentaro Yuda
KKKayo Kure
Kayo Kure
YYYasuo Yanagi
Yasuo Yanagi
To describe detailed clinical features of eyes with focal choroidal excavation. Twenty-one eyes of 17 patients with focal choroidal excavation were retrospectively studied. All eyes underwent thorough examination including funduscopy, visual field analysis, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, and B-scan ultrasonography. Patients' age ranged between 25 years and 70 years. Four patients (24%) were affected bilaterally. Spherical equivalent of refractive error ranged from 0.5 diopters to -10.0 diopters (D). Funduscopic examination showed hypopigmentation (n = 12) and yellowish plaquelike appearances (n = 2). Indocyanine green angiography showed not only filling defects at the excavation (n = 16) but also choroidal vascular hyperpermeability (n = 7) and punctate hyperfluorescent spots (n = 7). Cicatrized subretinal neovascularization was seen in three eyes. The mean follow-up period was 37 months (6-66 months). There was no change in the appearance of excavation. Central serous chorioretinopathy (n = 1) and choroidal neovascularization (n = 1) developed during follow-up. Background factors and ophthalmic findings are similar to those that have been reported previously, including relatively stable findings even after a long observation and the occurrence of central serous chorioretinopathy and choroidal neovascularization. Bilateral cases are not rare in the current cohort, and choroidal vascular hyperpermeability is frequently observed in indocyanine green angiography, suggesting there were choroidal hemodynamic changes around the excavation.

11 November 2020 in Scientific Reports
Verified
Journal Article
Open access
PDF file
MYMasahiro Yamanari
Masahiro Yamanari
MMMutsuki Mase
Mutsuki Mase
RORyo Obata
Ryo Obata
MMMitsuhiro Matsuzaki
Mitsuhiro Matsuzaki
TMTakahiro Minami
Takahiro Minami
YKYasuo Kurimoto
Yasuo Kurimoto
Imaging of melanin in the eye is important as the melanin is structurally associated with some ocular diseases, such as age-related macular degeneration. Although optical coherence tomography (OCT) cannot distinguish tissues containing the melanin from other tissues intrinsically, polarization-sensitive OCT (PS-OCT) can detect the melanin through spatial depolarization of the backscattered light from the melanin granules. Entropy is one of the depolarization metrics that can be used to detect malanin granules in PS-OCT and valuable quantitative information on ocular tissue abnormalities can be retrived by correlating entropy with the melanin concentration. In this study, we investigate a relationship between the melanin concentration and some depolarization metrics including the entropy, and show that the entropy is linearly proportional to the melanin concentration in double logarithmic scale when noise bias is corrected for the entropy. In addition, we also confirm that the entropy does not depend on the incident state of polarization using the experimental data, which is one of important attributes that depolarization metrics should have. The dependence on the incident state of polarization is also analyzed for other depolarization metrics.

1 July 2008 in American Journal of Ophthalmology
Verified
Journal Article
Closed access
TUTakashi Ueta
Takashi Ueta
AIAya Iriyama
Aya Iriyama
JFJasmine Francis
Jasmine Francis
HTHidenori Takahashi
Hidenori Takahashi
TATomoko Adachi
Tomoko Adachi
YYYasuo Yanagi
Yasuo Yanagi

1 August 2006 in Journal of Ocular Pharmacology and Therapeutics
Verified
Journal Article
Closed access
HTHidenori Takahashi
Hidenori Takahashi
RORyo Obata
Ryo Obata
YTYasuhiro Tamaki
Yasuhiro Tamaki
An oral, multitargeted receptor tyrosine kinase inhibitor, SU11248, inhibits vascular endothelial growth factor receptor 2 (VEG FR2, kinase domain receptor F1K1), platelet-derived growth factor receptor, stem cell factor receptor (Kit), and fetal liver tyrosine kinase 3. In this study, we administered SU11248 beyond the completion of an experimental choroidal neovascularization (CNV) model to determine whether CNV growth can be inhibited in vivo. C57B6J mice were treated with daily oral administration (40, 80, and 150 mg/kg) of SU11248 during 5 days after diode laser endophotocoagulation and subjected to angiographic examination and histological analysis. Intensity of fluorescein leakage from the experimental CNV decreased significantly compared to the control eyes. Histological study also revealed that the volume of CNV membrane was significantly reduced in the SU11248-treated eyes. Oral administration of this compound is potentially beneficial in treating CNV caused by age-related macular degeneration (AMD) and other causal diseases. Considering the tolerance the clinical studies for malignant tumors previously demonstrated, further studies to evaluate the clinical efficacy of the drug for AMD might be indicated.

27 August 2019 in Scientific Reports
Verified
Journal Article
Open access
PDF file
AFAsahi Fujita
Asahi Fujita
YAYurika Aoyama
Yurika Aoyama
STSaori Tsuneyoshi
Saori Tsuneyoshi
ASAya Sugiura
Aya Sugiura
KAKeiko Azuma
Keiko Azuma
RORyo Obata
Ryo Obata
Central serous chorioretinopathy (CSC) usually resolves spontaneously; however, in some patients, it can be chronic and visual impairment remains even after resolution of the serous retinal detachment. The impaired photoreceptor cells often present with disrupted ellipsoid zone (EZ) on optical coherence tomography (OCT). In this study, the integrity of EZ was quantified by calculating the index of residual EZ, identified on binarized OCT images from 25 eyes of 23 patients with resolved CSC. To estimate residual EZ, integrity of residual EZ with the central horizontal line on the fovea (rEZc) and average integrity of residual EZ within 3 × 3-mm macular area (rEZave) were investigated. The interrater reliability of the method was assessed using the intraclass correlation coefficient (ICC). The relationship between LogMAR VA and age, central retinal thickness, central choroidal thickness, rEZc, and rEZave were evaluated using the linear mixed model. Retinal sensitivity was measured with the MP-3 microperimeter and similar analyses were iterated for mean retinal sensitivity (MS). ICC values were 0.938 with rEZc and 0.979 with rEZave. rEZc was significantly related to LogMAR VA (p = 0.039). rEZave was significantly related to MS (p < 0.001). These results suggested potential usefulness of residual EZ to predict visual function in resolved CSC.