Hiroki Sano, Kazuhiko Namekata, Masanori Niki, Kentaro Senba, Fumiko Murao, Takayuki Harada and Yoshinori Mitamura : Ocular expression of cyclin-dependent kinase 5 in patients with proliferative diabetic retinopathy., Journal of Diabetes Investigation, Vol.13, No.4, 628-637, 2022.
(要約)
Inhibition of peroxisome proliferator-activated receptor gamma (PPARγ) phosphorylation mediated by cyclin-dependent kinase 5 (Cdk5) is one of the main mechanisms of action of antidiabetic drugs. In this study, we analyzed the ocular expression and activation of Cdk5 in patients with proliferative diabetic retinopathy (PDR).
Yoshinori Mitamura, Tserennadmid Enkhmaa, Hiroki Sano, Masanori Niki, Fumiko Murao, Mariko Egawa, Shozo Sonoda and Taiji Sakamoto : Changes in choroidal structure following intravitreal aflibercept therapy for retinal vein occlusion., The British journal of Ophthalmology, Vol.105, No.5, 704-710, 2021.
(要約)
RVO induces substantial oedema of the choroidal stromal area that is detectable by binarisation of EDI-OCT images. This stromal oedema likely stems from high intraocular vascular endothelial growth factor levels. Changes in choroidal structure may be used to assess severity and prognosis of RVO.
Toshihiko Nagasawa, Hitoshi Tabuchi, Hiroki Masumoto, Shoji Morita, Masanori Niki, Zaigen Ohara, Yuki Yoshizumi and Yoshinori Mitamura : Accuracy of Diabetic Retinopathy Staging with a Deep Convolutional Neural Network Using Ultra-Wide-Field Fundus Ophthalmoscopy and Optical Coherence Tomography Angiography., Journal of Ophthalmology, Vol.2021, 2021.
(要約)
The combination of Optos and OCTA imaging with DCNN could detect DR at desirable levels of accuracy and may be useful in clinical practice and retinal screening. Although the combination of multiple imaging techniques might overcome their individual weaknesses and provide comprehensive imaging, artificial intelligence in classifying multimodal images has not always produced accurate results.
Fumiko Murao, Takamasa Kinoshita, Takashi Katome, Hiroki Sano, Masanori Niki and Yoshinori Mitamura : Suspected Gentamicin-Induced Retinal Vascular Occlusion after Vitrectomy., Case Reports in Ophthalmology, Vol.11, No.2, 473-480, 2020.
(要約)
Retinal vascular occlusion after ocular surgery is a rare but serious complication. A history of cardiovascular diseases, retrobulbar anesthesia injection, high intraocular pressure during the perioperative period, and drug toxicity have been reported as possible causative factors. We report here two cases of multiple retinal vascular occlusions after the subconjunctival injection of gentamicin at the end of uncomplicated 25-gauge vitrectomy. Case 1 was a 61-year-old man who developed a macular hole in the right eye. Phacovitrectomy with gas tamponade was performed. On postoperative day (POD) 1, dot hemorrhage was observed on the temporal side of the optic disk. On POD10, macular whitening, retinal hemorrhage, and multiple occlusion of retinal arteries and veins were observed. Case 2 was a 51-year-old woman who was diagnosed with rhegmatogenous retinal detachment in the right eye and underwent phacovitrectomy with gas tamponade. On POD3, macular whitening with cotton wool spots and retinal hemorrhage were observed with macular ischemia owing to occlusion of retinal arteries and veins. In both cases, subconjunctival injection of gentamicin given at the end of surgery was the most suspected cause of retinal vascular occlusion.
Mariko Egawa, Yoshinori Mitamura, Masanori Niki, Hiroki Sano, Gen Miura, Akihiro Chiba, Shuichi Yamamoto, Shozo Sonoda and Taiji Sakamoto : CORRELATIONS BETWEEN CHOROIDAL STRUCTURES AND VISUAL FUNCTIONS IN EYES WITH RETINITIS PIGMENTOSA, Retina, Vol.39, No.12, 2399-2409, 2019.
(要約)
To investigate the choroidal structures in the enhanced depth imaging optical coherence tomographic images in eyes with retinitis pigmentosa (RP) and to determine correlations between the choroidal structures and visual functions. The enhanced depth imaging optical coherence tomographic images of 100 eyes with typical RP and 60 age-, sex-, and axial length-matched normal eyes were binarized using ImageJ. The cross-sectional luminal and stromal areas of the inner and outer subfoveal choroid of 1,500-µm width were measured. The inner choroid included the choriocapillaris and medium vessel layer, and the outer choroid included the larger vessel layer. In the inner choroid, the luminal area and the ratio of luminal/total choroidal area (L/C ratio) were significantly smaller in RP than in controls (P = 0.010, P < 0.001, respectively), whereas the stromal area was not significantly different (P = 0.114). The inner choroidal L/C ratio was significantly correlated with the best-corrected visual acuity, mean deviation, foveal sensitivity, width of the ellipsoid zone, and central foveal thickness in RP after adjusting for the axial length, age, and sex (all P < 0.005). The significant correlations between the inner choroidal structures and the visual functions and retinal structures indicate that the choroidal structures are altered in association with the progression of RP.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
Daisuke Nagasato, Hitoshi Tabuchi, Hiroki Masumoto, Hiroki Enno, Naofumi Ishitobi, Masahiro Kameoka, Masanori Niki and Yoshinori Mitamura : Automated detection of a nonperfusion area caused by retinal vein occlusion in optical coherence tomography angiography images using deep learning., PLoS ONE, Vol.14, No.11, 2019.
(要約)
We aimed to assess the ability of deep learning (DL) and support vector machine (SVM) to detect a nonperfusion area (NPA) caused by retinal vein occlusion (RVO) with optical coherence tomography angiography (OCTA) images. The study included 322 OCTA images (normal: 148; NPA owing to RVO: 174 [128 branch RVO images and 46 central RVO images]). Training to construct the DL model using deep convolutional neural network (DNN) algorithms was provided using OCTA images. The SVM used a scikit-learn library with a radial basis function kernel. The area under the curve (AUC), sensitivity and specificity for detecting an NPA were examined. We compared the diagnostic ability (sensitivity, specificity and average required time) between the DNN, SVM and seven ophthalmologists. Heat maps were generated. With regard to the DNN, the mean AUC, sensitivity, specificity and average required time for distinguishing RVO OCTA images with an NPA from normal OCTA images were 0.986, 93.7%, 97.3% and 176.9 s, respectively. With regard to SVM, the mean AUC, sensitivity, and specificity were 0.880, 79.3%, and 81.1%, respectively. With regard to the seven ophthalmologists, the mean AUC, sensitivity, specificity and average required time were 0.962, 90.8%, 89.2%, and 700.6 s, respectively. The DNN focused on the foveal avascular zone and NPA in heat maps. The performance of the DNN was significantly better than that of SVM in all parameters (p < 0.01, all) and that of the ophthalmologists in AUC and specificity (p < 0.01, all). The combination of DL and OCTA images had high accuracy for the detection of an NPA, and it might be useful in clinical practice and retinal screening.
Takamasa Kinoshita, Hiroko Imaizumi, Miho Shimizu, Junya Mori, Akira Hatanaka, Shuichiro Aoki, Hirotomo Miyamoto, Masanori Iwasaki, Fumiko Murao, Masanori Niki, Hiroki Sano, Shozo Sonoda, Taiji Sakamoto and Yoshinori Mitamura : Systemic and Ocular Determinants of Choroidal Structures on Optical Coherence Tomography of Eyes with Diabetes and Diabetic Retinopathy., Scientific Reports, Vol.9, No.1, 2019.
(要約)
Knowledgeof the choroidal structures in eyes with diabetes and diabetic retinopathy (DR) should provide information on the pathogenesis of DR. A prospective study was performed to determine the systemic and ocular factors that affect the choroidal structures in eyes with diabetes. Two-hundred consecutive diabetic subjects consisted of 160 treatment-naïve patients with different stages of DR and 40 patients with proliferative DR with prior panretinal photocoagulation (PRP). All underwent blood and urine tests and enhanced depth imaging optical coherence tomography (EDI-OCT). The cross-sectional EDI-OCT images of the subfoveal choroid were binarized to measure the total choroidal area (TCA), luminal area, and stromal area. Multivariate regression analyses were performed to determine the systemic and ocular factors that were significantly correlated with the choroidal structures. The subfoveal choroidal thickness, TCA, luminal area, and stromal area were larger at more advanced stage of DR, and smaller in eyes with PRP than those without (P < 0.001). The TCA and stromal area were significantly and positively correlated with the degree of albuminuria (P = 0.034, P = 0.025, respectively). The choroidal lumen and stroma may increase as the stages of DR progress and decrease after PRP. Albuminuria may be associated with the choroidal stromal edema.