Biomedical subjects

Motohiro Shirakashi

Publications and source records attributed to Motohiro Shirakashi.

12 recordsLinked to original sources

PubMed2005

Measurement of intraocular pressure using the NT-4000: a new non-contact tonometer equipped with pulse synchronous measurement function.

PURPOSE: NT-4000 (Nidek Co. Ltd., Gamagori, Japan) is a new non-contact tonometer (NCT) equipped with pulse synchronous measurement function that can measure intraocular pressure (IOP) synchronized with the ocular pulse. The purpose of this study was to evaluate the usefulness of NT-4000 in normal subjects and in patients with glaucoma and ocular hypertension. METHODS: This study included 175 eyes of 175 subjects. Firstly, the IOP was measured using NT-4000 without the pulse synchronous measurement function (NTn). Secondly, the IOP at peak, middle, and trough phases of the pulse signal were measured using NT-4000 with the pulse synchronous measurement function (NTp, NTm, NTt, respectively). Additionally, the IOP was measured with Goldmann applanation tonometer (GT). The coefficient of variation (CV) of three readings in the NCT measurements was used to evaluate the intra-session reproducibility. Statistical comparisons were performed using Wilcoxon signed rank test and one-way analysis of variance with Scheffe's test. Linear regression analysis was used to calculate correlation coefficients. P values less than 0.05 were accepted as statistically significant. RESULTS: The CV of NTn, NTp, NTm, and NTt were 6.4%, 5.5%, 4.9%, and 5.2%, respectively. The CV of NTp, NTm, and NTt were significantly smaller than that of NTn (P = 0.007, P < 0.001, P < 0.001, respectively). NTp was significantly higher than NTt (P = 0.038). GT was significantly correlated with NTn, NTp, NTm, and NTt (r = 0.898, P < 0.001; r = 0.912, P < 0.001; r = 0.908, P < 0.001; r = 0.900, P < 0.001, respectively). CONCLUSION: NT-4000 can detect the fluctuation of IOP associated with the ocular pulse.

Adult↗

PubMed2004

Statistical evaluation of the diagnostic accuracy of methods used to determine the progression of visual field defects in glaucoma.

OBJECTIVE: To evaluate trend-type analyses to judge the progression of visual field damage (VFD) of glaucoma in terms of ratios of making judgments of progression and specificity, and to report a new method. DESIGN: Retrospective analysis of visual field (VF) results of actual glaucoma cases and those simulated by computer, and receiver operating characteristic curve analysis of performance of methods to judge the progression of VFD. PARTICIPANTS: One hundred five eyes of 105 open-angle glaucoma (OAG) patients with progressing VFD and 355 eyes of 355 clinically stable OAG patients for VF simulation from 4 university-based referral practices. METHODS: Methods using regression analysis of total deviation (TD), mean deviation (MD), mean TD of a sectored VF, and original scoring used in the Advanced Glaucoma Intervention Study (AGIS) were compared. A VF test was repeated twice in a short period on the 355 stable OAG eyes, and test-retest fluctuation, including variance at each test point and covariance between 2 test points, was calculated to simulate stable glaucomatous VF series by computer. The sensitivity of each method was calculated with 105 progressing VF series, and specificity was calculated with 10,000 simulated stable glaucomatous VF series. MAIN OUTCOME MEASURES: Sensitivity (ratios of making judgments of progression), specificity, and diagnostic power. RESULTS: The methods using the TD slope on one test location showed a sensitivity of 0.848 to 1.000, with a specificity of 0.105 to 0.721, and on 2 adjacent test locations showed a sensitivity of 0.848, with a specificity of 0.722. A significant negative MD slope with P<0.05 showed a sensitivity of 0.524, with a specificity of 0.945. The method using a sectored VF showed a sensitivity of 0.695, with a high specificity of 0.946. The AGIS method showed a sensitivity of 0.305 to 0.467, with a very high specificity of 0.999 to 1.000. The method using previously reported mathematically sectored VFs showed a sensitivity of 0.790, with a specificity of 0.900, and higher diagnostic power (1.69) than the others in this study population. CONCLUSIONS: Most of the methods using the TD slope were characterized by high sensitivity, the AGIS method had a very high specificity, and those using VF sectors had reasonable sensitivity and specificity.

Adolescent↗

PubMed2004

Relationship between indices of Humphrey perimetry and Frequency Doubling Technology Perimetry in glaucoma.

PURPOSE: To study whether the correlation between indices of Humphrey perimetry and Frequency Doubling Technology (FDT) perimetry differs in the early and later stages of glaucoma. METHODS: This study included 200 eyes of 200 patients with primary open-angle glaucoma or normal-tension glaucoma. The eyes were classified into the early and later stages by the median value (-4.51 dB) (Classification 1; n = 100 and 100, respectively) or the average value of the maximum and minimum values (-11.90 dB) (Classification 2; n = 165 and 35, respectively) of mean deviation (MD) obtained from a set of measurements with the Humphrey Full-Threshold 30-2 program in all eyes. The correlation between MD (H-MD) or pattern standard deviation (PSD) (H-PSD), as obtained from another set of measurements with the Humphrey Full-Threshold 30-2 program, and MD (F-MD) or PSD (F-PSD), as calculated by the Full-Threshold N-30 program of FDT perimetry, were evaluated using linear regression analysis. RESULTS: Overall, H-MD and H-PSD significantly correlated with F-MD (r = 0.713; P < 0.001) and F-PSD (r = 0.731; P < 0.001), respectively. In each of Classifications 1 and 2, H-MD and H-PSD significantly correlated with F-MD and F-PSD, respectively, both in the early and later stages. However, in each classification, the correlation between H-MD and F-MD differed significantly between the two stages (Classification 1; P < 0.001; Classification 2, P = 0.003), while the correlation between H-PSD and F-PSD did not differ significantly between the two stages. CONCLUSION: The degree of correlation between H-MD and F-MD differed between the early and later stages of glaucoma.

Female↗

PubMed2004

Optic disc topography as measured by confocal scanning laser ophthalmoscopy and visual field loss in Japanese patients with primary open-angle or normal-tension glaucoma.

PURPOSE: To determine whether differences in the optic disc topography and those in the relation between the optic disc topography and visual field indices exist between Japanese patients with primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG). METHODS: The study included consecutive Japanese patients with POAG (n = 60) or NTG (n = 60). Using the Heidelberg Retina Tomograph (HRT), we measured disc area, cup area, cup-to-disc area ratio, rim area, cup volume, rim volume, cup shape measure, and height variation contour. Each HRT parameter was measured in the total optic disc and in its four 90 degree quadrants (superior, temporal, inferior, and nasal). The mean deviation for the entire field and the sum of the total deviation values corresponding to each optic disc quadrant were calculated using the Humphrey full-threshold 30-2 program. RESULTS: No significant differences were found between the POAG and NTG groups for any HRT parameter either globally or regionally. There were no significant differences between the two groups in the correlation coefficients between any HRT parameter and the corresponding visual field indices either globally or regionally. CONCLUSION: No significant differences were apparent between Japanese patients with POAG and NTG both in the optic disc parameters as measured by HRT and in the degree of correlation between HRT parameter and the corresponding visual field indices.

Female↗

PubMed2004

[A case of acute angle-closure glaucoma secondary to annular ciliochoroidal detachment after unsutured cataract surgery].

BACKGROUND: We report a patient with acute angle-closure glaucoma secondary to annular ciliochoroidal detachment after unsutured cataract surgery. CASE: An 82-year-old man was diagnosed with bilateral shallow central anterior chamber depth, flat peripheral anterior chamber, and elevated intraocular pressure. One day previously he had undergone uncomplicated unsutured cataract surgery in the right eye and eight days previously, in the left eye. Ultrasound biomicroscopy revealed annular ciliochoroidal detachment in both eyes. Treatment with intravenous methyl prednisolone deepened the anterior chamber and reduced intraocular pressure. CONCLUSION: Annular ciliochoroidal detachment may lead to anterior rotation of the ciliary body and angle-closure. This clinical entity is indistinguishable from malignant glaucoma when the fundus cannot be visualized.

Acute Disease↗

PubMed2003

Relationship between optic nerve head microcirculation and visual field loss in glaucoma.

PURPOSE: To study the relationship between optic nerve head blood flow velocity and visual field loss in patients with primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG). METHODS: This study included 44 eyes of 44 patients with POAG and 44 eyes of 44 patients with NTG. To evaluate optic nerve head blood flow velocity, the square blur rate (SBR) was measured by means of laser speckle flowgraphy. The correlation between SBR and Humphrey visual field indices was evaluated with linear regression analysis. RESULTS: In the NTG group, the average SBR at the superior and inferior temporal neuroretinal rim was positively correlated with mean deviation (MD) (r = 0.349, p = 0.020). The SBR at the superior or inferior temporal neuroretinal rim was positively correlated with the sum of the total deviations in the corresponding hemifields (r = 0.299, p = 0.049; r = 0.354, p = 0.019, respectively). The correlations between SBR and MD did not differ statistically between the NTG and POAG groups; however, no significant correlation between SBR and visual field indices was observed in the POAG group. CONCLUSION: These results suggested that the change in the circulation of the optic nerve head may be related to visual field damage in the NTG group but may be less involved in visual field damage in the POAG group.

Antihypertensive Agents↗

PubMed2003

Localization and expression of chondromodulin-I in the rat cornea.

The localization and expression in the rat cornea of chondromodulin-I (ChM-I), an inhibitory angiogenesis factor, were examined by immunohistochemistry, Western blot analysis, ribonuclease protection assay, and real-time PCR assay. We found immunoreactivity for ChM-I in the epithelial layer but not the stromal layer or endothelial layer in the cornea, in addition to the positive ChM-I immunoreactivity in other sites in the eye such as the sclera, retina, and ciliary body. The ChM-I immunoreactivity was most intense at the outside of the basal cells and in their cytoplasm while the intensity of the immunoreactivity decreased gradually from the wing cells to the superficial cells in the corneal epithelial layer. No reactivity however, was detected in the Bowman's membrane or conjunctival epithelial cells which had continuity with the corneal epithelial cells. The expression of ChM-I mRNA was demonstrated in the cornea at one-third less intensity than that in the sclera with choroids and retinal pigment epithelium by ribonuclease protection assay and real-time PCR. ChM-I in the corneal epithelial layer may prevent neovascularization and maintain avascularity in the cornea.

Animals↗

PubMed2003

[A case of steroid-induced glaucoma after radial keratotomy].

BACKGROUND: We report a patient who was diagnosed as having steroid-induced glaucoma after radial keratotomy(RK) and suffered from severe visual field defect. CASE: A 29-year-old man underwent RK for both eyes. After the operation, he was treated for six months with topical medication including 0.1% and 0.01% betamethasone without measuring intraocular pressure(IOP). When he consulted an ophthalmologist, his IOP was 43 mmHg in the right eye and 51 mmHg in the left eye. At our initial examination, his IOP was 8 mmHg in the right eye and 10 mmHg in the left eye with 750 mg acetazolamide peroral, 0.5% timolol maleate, and latanoprost eyedrops. There were RK 16 incisions on the cornea and we found severe glaucomatous visual field loss. Finally we performed trabeculotomy in both eyes for IOP control with conservative therapy. CONCLUSION: As the keratorefractive surgery becomes popular, we must be careful of problems, such as steroid-induced glaucoma, and the change of refraction following the change of IOP.

Administration, Topical↗

PubMed2002

Myopia and advanced-stage open-angle glaucoma.

OBJECTIVE: To investigate the effect of myopic refraction on the central visual field in patients with advanced open-angle glaucoma (OAG). DESIGN: Multicenter cross-sectional study. PARTICIPANTS: Three hundred thirteen OAG eyes (176 eyes of 176 primary open-angle glaucoma [POAG] patients and 137 eyes of 137 normal-tension glaucoma [NTG] patients) with clear ocular media and a mean deviation (MD) <-15 dB. Patients with a recorded maximum intraocular pressure (IOP) of 22 mmHg or greater were classified as POAG, and those with an IOP of 21 mmHg or less were classified as NTG. METHODS: Multiple regression analysis was used to study the influence of refraction on 12 central test points of the C30-2 Humphrey program, and the differences in visual field defects between POAG and NTG eyes were examined using logistic discriminant analysis. In the multiple regression analysis, total deviation (TD) of the 12 test points was graded and used as the dependent variable, and MD and the spherical equivalent refraction were the explanatory variables. In the logistic discrimination analysis, TD, MD, and refraction were covariants that determined the OAG subtypes. MAIN OUTCOME MEASURES: TD values of the 12 central test points (C30-2 program). RESULTS: Higher myopic refraction was significantly associated with more damage at a point just temporal and inferior to the fixation point in POAG eyes, whereas it was significantly associated with less damage at test points just temporal and superior to the fixation point in NTG eyes. After correcting for the influence of refraction, POAG eyes had significantly more damage at a test point just temporal and inferior to the fixation point, whereas NTG eyes had significantly more damage at those test points nasal and inferior to the fixation point. CONCLUSIONS: High myopia constitutes a threat to the remaining lower cecocentral visual field and is one of the factors that interfere with the quality of vision in advanced OAG with high IOP but not low IOP.

Cross-Sectional Studies↗

PubMed2002

Specificity and sensitivity of glaucoma detection in the Japanese population using scanning laser polarimetry.

AIMS: To investigate the usefulness of the scanning laser polarimeter (GDx; GDx Nerve Fiber Analyzer) for glaucoma detection in the Japanese population, and to investigate the difference in the thickness of retinal nerve fibre layer (RNFL) between normal tension glaucoma (NTG) and primary open angle glaucoma (POAG). METHODS: 69 eyes of 69 normal subjects and 115 eyes of 115 chronic open angle glaucoma patients (60 NTG and 55 POAG patients) were studied. The thickness of RNFL was measured with GDx. An eye was diagnosed as glaucomatous, if at least one original GDx variable showed p <5%. The difference in thickness of RNFL between the NTG and POAG groups was then investigated. RESULTS: 46 normal eyes (66.7%) were diagnosed as not glaucomatous (no variables showing p <5%), and 93 glaucomatous eyes (46 NTG and 47 POAG eyes) (80.9%) were diagnosed as glaucomatous. Actual values of average thickness, ellipse average, superior average, and superior integral were significantly lower in the POAG group than those in the NTG group. CONCLUSIONS: New variables which elucidate focal RNFL defects or early changes are needed to improve the moderate detection ability found in this present study. The pattern of the change in RNFL may differ in NTG and POAG groups.

Adult↗

PubMed2002

[Changes in filtering bleb with laser treatment after non-penetrating trabeculectomy].

PURPOSE: Ultrasound biomicroscopy(UBM) was performed on filtering blebs with laser treatment including laser gonioplasty(GP), laser iridotomy(LI), and YAG laser trabeculopuncture(YLT) after non-penetrating trabeculectomy(NPT). The filtering blebs were grouped into four types, L, H, E and F, and the spaces under the scleral flap were classified into three. La, S, and N. CASES: In case 1, an F type, an S bleb was not changed despite laser treatment 9 months after NPT. In case 2, YLT was performed twice to release the incarcerated iris. The filtering bleb was changed to the L type, an La bleb. In case 3, an F type, an S bleb was turned into an H type after GP, LI, and YLT. In case 4, GP effectively released peripheral anterior synechia formation and the filtering bleb was kept as an L type, La. CONCLUSION: Appropriate laser treatment may be effective in turning a flattened and localized bleb into a good filtering bleb.

Anterior Eye Segment↗

PubMedDate not supplied

Topographic characteristics of the optic nerve head measured with scanning laser tomography in normal Japanese subjects.

PURPOSE: Few studies have been performed regarding the topographic information obtained with the Heidelberg retina tomograph (HRT) in normal Japanese. In this study, we examined the factors influencing optic disc parameters and hemisphere symmetry obtained with the HRT in normal Japanese subjects. METHODS: Mean values and the standard deviation range for the main HRT parameters were evaluated in 223 eyes of 223 normal Japanese subjects. The influence of age, sex, and disc size on HRT topographic data was analyzed. The superior and inferior hemisphere topographic parameters were compared. RESULTS: Disc area showed a significant difference by sex (P = 0.0493). Rim volume (r = -0.208, P = 0.019), height variation contour (r = -0.275, P = 0.001), and mean retinal nerve fiber layer (RNFL) thickness (r = -0.366, P = 0.001) declined with age. All parameters except height variation contour and mean RNFL thickness showed a clinically significant correlation with disc size (-0.159 < r < 0.719, P < 0.01). Cup parameters in the superior hemisphere were significantly greater than those in the inferior hemisphere. In contrast, rim parameters in the superior hemisphere were significantly smaller than those in the inferior hemisphere. CONCLUSIONS: Some factors, namely, sex, age, and disc size, affected the optic disc parameters in the HRT measurements. Possible parameter asymmetry between the two hemispheres should be considered in normal eyes.

Adolescent↗