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289 result(s) for "Kimura, Shuhei"
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Assessment of tilt and decentration of crystalline lens and intraocular lens relative to the corneal topographic axis using anterior segment optical coherence tomography
To investigate the tilt and decentration of the crystalline lens and the intraocular lens (IOL) relative to the corneal topographic axis using anterior segment ocular coherence tomography (AS-OCT). A sample set of 100 eyes from 49 subjects (41 eyes with crystalline lenses and 59 eyes with IOLs) were imaged using second generation AS-OCT (CASIA2, TOMEY) in June and July 2016 at Okayama University. Both mydriatic and non-mydriatic images were obtained, and the tilt and decentration of the crystalline lens and the IOL were quantified. The effects of pupil dilation on measurements were also assessed. The crystalline lens showed an average tilt of 5.15° towards the inferotemporal direction relative to the corneal topographic axis under non-mydriatic conditions and 5.25° under mydriatic conditions. Additionally, an average decentration of 0.11 mm towards the temporal direction was observed under non-mydriatic conditions and 0.08 mm under mydriatic conditions. The average tilt for the IOL was 4.31° towards the inferotemporal direction relative to the corneal topographic axis under non-mydriatic conditions and 4.65° in the same direction under mydriatic conditions. The average decentration was 0.05 mm towards the temporal direction under non-mydriatic conditions and 0.08 mm in the same direction under mydriatic conditions. A strong correlation was found between the average tilt and decentration values of the crystalline lens and the IOL under both non-mydriatic and mydriatic conditions (all Spearman correlation coefficients, r ≥ 0.800; all P < 0.001). When measured using second generation AS-OCT, both the crystalline lens and the IOL showed an average tilt of 4-6° toward the inferotemporal direction relative to the corneal topographic axis and an average decentration of less than 0.12 mm towards the temporal direction. These results were not influenced by pupil dilation and they showed good repeatability.
En face image-based classification of diabetic macular edema using swept source optical coherence tomography
This retrospective study was performed to classify diabetic macular edema (DME) based on the localization and area of the fluid and to investigate the relationship of the classification with visual acuity (VA). The fluid was visualized using en face optical coherence tomography (OCT) images constructed using swept-source OCT. A total of 128 eyes with DME were included. The retina was segmented into: Segment 1, mainly comprising the inner nuclear layer and outer plexiform layer, including Henle’s fiber layer; and Segment 2, mainly comprising the outer nuclear layer. DME was classified as: foveal cystoid space at Segment 1 and no fluid at Segment 2 (n = 24), parafoveal cystoid space at Segment 1 and no fluid at Segment 2 (n = 25), parafoveal cystoid space at Segment 1 and diffuse fluid at Segment 2 (n = 16), diffuse fluid at both segments (n = 37), and diffuse fluid at both segments with subretinal fluid (n = 26). Eyes with diffuse fluid at Segment 2 showed significantly poorer VA, higher ellipsoid zone disruption rates, and greater central subfield thickness than did those without fluid at Segment 2 ( P  < 0.001 for all). These results indicate the importance of the localization and area of the fluid for VA in DME.
Assessment of epiretinal membrane formation using en face optical coherence tomography after rhegmatogenous retinal detachment repair
PurposeTo investigate epiretinal membrane (ERM) formation using en face optical coherence tomography (OCT) after vitrectomy for rhegmatogenous retinal detachment (RRD).MethodsWe retrospectively reviewed the medical records of 64 consecutive eyes (64 patients) with RRD treated by vitrectomy without ERM and internal limiting membrane peeling. ERMs and retinal folds were detected by B-scan and en face imaging. The maximum depth of retinal folds (MDRF) was quantified using en face imaging. ERM severity was staged using B-scan imaging. Main outcome measures were ERM detection rate with B-scan and en face imaging, MDRF, ERM staging, postoperative best-corrected visual acuity (BCVA; logarithm of the minimum angle of resolution), and risk factors for ERM formation.ResultsThe detection rate for ERM formation was significantly higher with en face imaging (70.3%) than with B-scan imaging (46.9%; P = 0.007). There was no significant difference in postoperative BCVA between eyes with ERM formation (0.06 ± 0.26) and those without ERM formation (0.01 ± 0.14; P = 0.298). Forty of 45 (88.9%) eyes with ERM formation were classified as stage 1. Twenty-seven of 45 (60.0%) eyes with ERM formation developed parafoveal retinal folds. The mean MDRF was 27.4 ± 32.2 μm. Multiple retinal breaks and a maximum retinal break size of ≥ 2 disc diameters were significantly associated with ERM formation (P = 0.033 and P = 0.031, respectively).ConclusionAlthough ERM formation was observed in 70.3% patients after RRD repair, the formed ERM was not severe and had minimal impact on the postoperative visual acuity.
Results of lamellar macular hole-associated epiretinal proliferation embedding technique for the treatment of degenerative lamellar macular hole
PurposeTo investigate the outcomes of embedding lamellar hole-associated epiretinal proliferation (LHEP) into retinal cleavage for the surgical treatment of degenerative lamellar macular hole (LMH).MethodsWe retrospectively reviewed the medical records of 34 consecutive eyes of degenerative LMH patients who underwent vitrectomy with LHEP embedding and who were followed up for at least 12 months. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), and macular structure preoperatively and at the final follow-up were compared.ResultsThe mean (±SD) follow-up period was 30.0 ± 17.7 months. Twelve patients (35.3%) were men, and the mean age was 69.6 ± 10.1 years. Twenty-three eyes (67.6%) underwent simultaneous cataract surgery. BCVA was significantly improved at the final visit, from 0.31 ± 0.25 logarithm of the minimum angle of resolution units to 0.10 ± 0.25 (P < 0.01). This improvement in mean BCVA at the final postoperative visit occurred regardless of whether the eyes underwent simultaneous cataract surgery, from 0.30 ± 0.26 preoperatively to 0.04 ± 0.16 (P < 0.01) in the “with cataract surgery” group and from 0.32 ± 0.26 preoperatively to 0.21 ± 0.35 (P < 0.05) in the “without cataract surgery” group. CRT was also significantly improved at the final visit, from 123.2 ± 42.6 μm preoperatively to 191.2 ± 42.6 μm (P < 0.01). External limiting membrane and ellipsoid zone defects were detected in 17 (50.0%) and 15 (44.1%) eyes, respectively, but these were resolved in 10 (58.8%) and 7 (46.7%) eyes, respectively, at the final visit. No intraoperative or postoperative complications were observed.ConclusionsEmbedding LHEP may be an effective and safe procedure to treat degenerative LMH.
Factors affecting foveal avascular zone in healthy eyes: An examination using swept-source optical coherence tomography angiography
To examine factors affecting foveal avascular zone (FAZ) area in healthy eyes using swept-source optical coherence tomography angiography (OCTA). This prospective, cross-sectional study included 144 eyes of 144 individuals (77 women, 67 men) with a best corrected visual acuity of at least 20/20 and no history of ocular disorders. The area of the superficial FAZ was assessed using OCTA. Age, gender, central retinal thickness (CRT), retinal vascular density, refractive error, and axial length were examined to determine associations with FAZ area. The mean age of the subjects was 42.1 ± 20.2 years (range: 10-79 years). The mean FAZ area was 0.32 ± 0.11 mm2, while the mean retinal vascular density was 35.53 ± 0.92%. Multivariate regression analysis was performed using FAZ area as the dependent variable and age, gender, CRT, retinal vascular density, refractive error, and axial length as independent variables. The results of this analysis demonstrate that CRT and retinal vascular density were significantly associated with FAZ area in our sample (P < 0.001, R2 = 0.425). Age, gender, refractive error, and axial length were not significantly correlated with FAZ area, while CRT and retinal vascular density were negatively correlated with FAZ area (CRT: P < 0.001, R2 = 0.356; retinal vascular density: P < 0.001, R2 = 0.189). OCTA results suggest that CRT and retinal vascular density negatively affect FAZ area in healthy eyes.
Effect of rhegmatogenous retinal detachment on preoperative and postoperative retinal sensitivities
This retrospective study investigated foveal and perifoveal retinal sensitivities using microperimetry before and after surgery for rhegmatogenous retinal detachment (RRD). Consecutive patients with RRD who underwent vitrectomy or scleral buckling were included. Comprehensive ophthalmological examinations, including microperimetry and swept-source optical coherence tomography, were performed before and 6 months after surgery. Pre- and postoperative retinal sensitivities at the fovea and 4 perifoveal measurement points farthest from the fixation point, both vertically and horizontally (superior, inferior, nasal, and temporal) were examined. A total of 34 foveal and 136 perifoveal measurement points in 34 eyes of 34 patients were evaluated. The postoperative retinal sensitivity was significantly higher than the preoperative value at foveal and perifoveal points with ( P  < 0.001 for both) and without (fovea: P  = 0.005, perifovea: P  < 0.001) RRD. The postoperative retinal sensitivity was significantly lower at foveal ( P  < 0.01) and perifoveal ( P  < 0.001) points with preoperative RRD than at points without preoperative RRD; furthermore, it was significantly better at points with ellipsoid zone (Ez) continuity than at points with Ez discontinuity (fovea: P  < 0.01, perifovea: P  < 0.001). RRD deteriorates retinal sensitivity, regardless of its presence or absence at the measurement point before surgery. Postoperative Ez continuity is important for good postoperative retinal sensitivity.
A factor for predicting simultaneous internal limiting membrane peeling during epiretinal membrane removal: swept-source optical coherence tomography-based evaluation of epiretinal membrane adhesion to the retina
Purpose To investigate preoperative factors associated with simultaneous internal limiting membrane (ILM) peeling during epiretinal membrane (ERM) removal. Study design Observational cross-sectional study. Methods We retrospectively reviewed 60 eyes with idiopathic ERM that underwent vitrectomy. The gap between the ERM and ILM was visualized using en face optical coherence tomography. The depth and width of the ERM–ILM gap at the initiation site of ERM removal were measured, and the relationship between preoperative factors including these parameters and simultaneous ILM peeling during ERM removal was investigated. Results The ILM was simultaneously peeled during ERM removal in 30 eyes, but not in the other 30 eyes. Age was significantly higher (P = 0.017) and the width of the ERM–ILM gap was significantly smaller (P < 0.001) in the simultaneous ILM peeling (+) group than in the simultaneous ILM peeling (–) group. Multivariate logistic regression analysis confirmed the width of the ERM–ILM gap as a significant negative predictor for simultaneous ILM peeling (odds ratio, 0.992; 95% confidence interval, 0.986–0.997; P = 0.003). Receiver operating characteristic curve analysis of the width of the ERM–ILM gap revealed that the optimal cutoff for predicting simultaneous ILM peeling was 187.1 µm. Conclusion The small width of the ERM–ILM gap at the initiation site of ERM removal was significantly associated with simultaneous ILM peeling, indicating that the adhesion strength between the ERM and ILM at the initial ERM grasping site determines whether simultaneous ILM peeling will occur during ERM removal.
Cytotoxic effects of alteplase, a recombinant tissue plasminogen activator, on human retinal pigment epithelial cells
Purpose To evaluate the cytotoxic effects of alteplase, a recombinant tissue plasminogen activator, and its additives on human retinal pigment epithelial (hRPE) cells. Study design Laboratory study. Methods We evaluated the cytotoxic effects of alteplase on human fetal RPE (hfRPE) cells, human induced pluripotent stem cell-derived RPE (hiPS-RPE), and ARPE-19 cells, as well as the cytotoxic effects of L-arginine and polysorbate 80, two additives of alteplase, on hfRPE cells. The effects of alteplase on the production of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) from hfRPE cells and the transepithelial resistance (TER) of hiPS-RPE cells were also assessed. The type of cell death induced by alteplase was investigated using ethidium homodimer III and FITC-Annexin V staining and terminal transferase deoxyuridine triphosphatase nick-end labeling. Results Alteplase reduced the viability of hfRPE cells significantly in a dose- and time-dependent manner. The reaction of hiPS-RPE and ARPE19 cells to alteplase was similar to that of hfRPE cells. Out of L-arginine and polysorbate 80, only treatment with L-arginine significantly reduced the viability of hfRPE cells. Alteplase (83 μg/ml, 6 h) had no significant effect on the production of VEGF and PEDF from hfRPE cells. Alteplase decreased the TER of hiPS-RPE cells in a dose- and time-dependent manner and induced necrosis as the type of cell death. Conclusion Alteplase can be cytotoxic to human RPE cells in a concentration- and time-dependent manner, with L-arginine being a possible causative factor.
Unlocking sperm chromatin at fertilization requires a dedicated egg thioredoxin in Drosophila
In most animals, the extreme compaction of sperm DNA is achieved after the massive replacement of histones with sperm nuclear basic proteins (SNBPs), such as protamines. In some species, the ultracompact sperm chromatin is stabilized by a network of disulfide bonds connecting cysteine residues present in SNBPs. Studies in mammals have established that the reduction of these disulfide crosslinks at fertilization is required for sperm nuclear decondensation and the formation of the male pronucleus. Here, we show that the Drosophila maternal thioredoxin Deadhead (DHD) is specifically required to unlock sperm chromatin at fertilization. In dhd mutant eggs, the sperm nucleus fails to decondense and the replacement of SNBPs with maternally-provided histones is severely delayed, thus preventing the participation of paternal chromosomes in embryo development. We demonstrate that DHD localizes to the sperm nucleus to reduce its disulfide targets and is then rapidly degraded after fertilization. In many animals, sperm DNA compaction is achieved by disulfide bonds between the sperm nuclear proteins that replace the histones. Here, the authors provide evidence that Drosophila maternal thioredoxin Deadhead is required to unlock the sperm chromatin upon fertilization.
Accuracy of ultrasound vs. Fourier-domain optic biometry for measuring preoperative axial length in cases of rhegmatogenous retinal detachment
Purpose To identify a method for accurately measuring preoperative axial length (AL) in cases of rhegmatogenous retinal detachment (RRD). Study design Retrospective study. Methods This retrospective study included 83 eyes of 83 patients who underwent vitrectomy for RRD and had both preoperative and postoperative data for AL. Preoperative AL measurements for the affected eye were obtained using ultrasound (aUS-AL) and compared with those for affected and fellow eyes measured using optical biometry (aOB-AL and fOB-AL, respectively). Absolute differences between preoperative aUS-AL, aOB-AL, or fOB-AL measurements and postoperative AL (aPost-AL) were examined. Results In the 41 eyes without macular detachment, the absolute difference between aOB-AL and aPost-AL (0.06±0.07 mm) was significantly smaller than between aUS-AL and aPost-AL (0.21±0.18 mm) and that between fOB-AL and aPost-AL (0.29±0.35 mm) (P = 0.017 and P < 0.001, respectively). In the 42 eyes with macular detachment, the absolute difference between aOB-AL and aPost-AL (1.22±2.40 mm) was significantly larger than between aUS-AL and aPost-AL (0.24±0.24 mm) and between fOB-AL and aPost-AL (0.35±0.49 mm) (P = 0.006, P = 0.016, respectively). Conclusion The current findings suggest that aOB-AL is more accurate than aUS-AL or fOB-AL in cases of RRD without macular detachment, while aUS-AL or fOB-AL is more accurate than aOB-AL in cases with macular detachment.