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Biomedical subjects

Yozo Miyake

Publications and source records attributed to Yozo Miyake.

At least 19 recordsLinked to original sources
PubMed2004

The relationship between intraocular pressure and refractive error adjusting for age and central corneal thickness.

PURPOSE: To investigate the relationship between intraocular pressure (IOP) and refractive errors after adjusting for age, central corneal thickness (CCT), and other related factors. METHODS: IOP, CCT and refractive errors were measured in the right eyes of 1855 subjects, aged 40-82 years, in a cross-sectional study design. Subjects were divided into groups by refractive status: hyperopia, emmetropia, mild myopia, moderate myopia, or high myopia. With adjustments for age, CCT, blood pressure, obesity, education, hypertension, diabetes, and smoking status, IOP was estimated for each refractive status using a general linear model. RESULTS: IOP increased with advancing degrees of myopia, even after adjustment for age, CCT, and other related factors (p = 0.011). Estimated IOP of moderate myopia was significantly higher than that of emmetropia (p = 0.022). CONCLUSIONS: Our results confirm the positive association between IOP and increasing degrees of myopia. This finding would support the hypothesis that the relationship between glaucoma and myopia might be pressure mediated.

Adult↗
PubMed2004

Delayed regeneration of foveal cone photopigments in Vogt-Koyanagi-Harada disease at the convalescent stage.

PURPOSE: To evaluate the physiological characteristics of the macula in patients with Vogt-Koyanagi-Harada disease during the convalescent stage with specific reference to the kinetics of foveal cone photopigment regeneration. METHODS: Six eyes of three patients at the convalescent stage of Vogt-Koyanagi-Harada disease were studied. All the eyes had best corrected visual acuity of 1.0 or better and had had no recurrence of inflammation for at least 12 months after the last episode. Foveal cone densitometry (FCD), focal macular electroretinograms, color vision tests, two-color perimetry, and optical coherence tomography (OCT) were performed. RESULTS: No regeneration of cone photopigments was detected within the 7-minute testing time by FCD in all eyes at the first examination after the last episode. However, the other functional tests were normal, and the OCT-determined macular morphology was also normal. The regeneration kinetics of the foveal cone photopigment improved in three of six eyes at 36, 37, and 19 months after the last episode, whereas the other three remained delayed at 18, 18, and 49 months. CONCLUSIONS: These findings suggest that a disorder of the foveal cone photopigment regeneration, and its recovery, requires a significantly longer time than that of other macular functions in some patients with Vogt-Koyanagi-Harada disease.

Adult↗
PubMed2003

Retinal and optic disc atrophy associated with a CACNA1F mutation in a Japanese family.

OBJECTIVE: To describe retinal and optic disc atrophy and a progressive decrease of visual function in 2 Japanese brothers. Both had a mutation in the CACNA1F gene, the causative gene of incomplete congenital stationary night blindness (CSNB). METHODS: We studied observational case reports and performed comprehensive ophthalmologic examinations including best-corrected visual acuity, biomicroscopy, ophthalmoscopy, fundus photography, and electroretinography. Genomic DNA was extracted from the peripheral blood, and all 48 exons of the CACNA1F gene were directly sequenced. RESULTS: The 2 brothers had retinal and optic disc atrophy and a progressive reduction of visual acuity with increasing age. Although these clinical features are not typical of previous patients with incomplete CSNB, both patients had an in-frame mutation with deletion and insertion in exon 4 of the CACNA1F gene. In both patients, the bright-flash, mixed rod-cone electroretinogram had a negative configuration, a characteristic of incomplete CSNB. However, the full-field scotopic and photopic electroretinograms were nonrecordable, indicating severe, diffuse retinal malfunction, which is not typical in incomplete CSNB. CONCLUSION: These findings indicate that a mutation of the CACNA1F gene may be associated with retinal and optic disc atrophy with a progressive decline of visual function. Clinical Relevance In patients with retinal and optic disc atrophy associated with negative-type electroretinograms, a CACNA1F gene mutation should be considered.

Amino Acid Sequence↗
PubMed2003

Mapping posterior vitreous detachment by optical coherence tomography in eyes with idiopathic macular hole.

PURPOSE: To determine the relationship between posterior vitreous detachment and idiopathic macular hole. DESIGN: Observational case series. METHODS: In a prospective study, the posterior hyaloid face was scanned from the posterior pole to the far periphery by optical coherence tomography in 25 eyes (22 patients) with an idiopathic macular hole (stage 1 = 1, stage 2 = 7, stage 3 = 10, and stage 4 = 7), and a map of the posterior vitreous detachment was constructed. RESULTS: One eye with a stage 1 macular hole had a posterior vitreous detachment confined to the vascular arcade, but attached to the fovea. In all seven eyes at stage 2, the detached posterior hyaloid enlarged upward beyond the superior vascular arcade, but stopped at the margin of inferior vascular arcade. In two cases, the posterior vitreous detachment also extended temporally and superonasally. In all cases, the vitreous face remained attached to the fovea. Six of the 10 eyes at stage 3 had larger partial posterior vitreous detachment that extended not only upward, but also beyond the inferior vascular arcade, while in the other four eyes, the size and position of the posterior vitreous detachment was similar to stage 2 macular holes. However, unlike stage 2, the posterior vitreous detachment included the fovea in all eyes. All seven eyes with a stage 4 macular hole had complete posterior vitreous detachment that extended to the far periphery in all directions. CONCLUSION: There is a close correlation between the stage of the macular hole and the degree of posterior vitreous detachment. This close correlation suggests that progression of idiopathic macular hole is related to enlargement of the posterior vitreous detachment.

Aged↗
PubMed2003

Reduced oscillatory potentials of the full-field electroretinogram of eyes with aphakic or pseudophakic cystoid macular edema.

PURPOSE: To report reduced oscillatory potentials (OPs) in the full-field electroretinogram (ERG) of eyes with aphakic or pseudophakic cystoid macular edema (CME). DESIGN: Observational case series. METHODS: Bright white flash full-field ERGs were recorded from 19 eyes of 19 patients (ages, 53-84 years) with aphakic or pseudophakic CME. Seven of the cases had uncomplicated phacoemulsification (PE) with implantation of a posterior chamber intraocular lens (PC-IOL) and 6 had posterior capsular rupture during phacoemulsification and aspiration with implantation of a PC-IOL. Four additional patients had uncomplicated intracapsular cataract extraction (ICCE), and 2 had secondary anterior chamber intraocular lens after ICCE. Their fellow eyes without CME served as controls. Cystoid macular edema was diagnosed as clinically significant by slit-lamp examination and by fluorescein angiography. The grading for severity of CME was based on the fluorescein angiography. The visual acuity ranged from 20/200 to 20/16. RESULTS: There were no significant differences in the mean amplitudes and implicit times of the a-waves and b-waves between the affected eyes and the fellow eyes. The mean summed amplitude of the OPs was significantly reduced in the affected eyes (P =.0003, Wilcoxon signed rank test). This decrease was strongly correlated with visual acuity (r =.779, P <.0001). The mean implicit time of the first OP was significantly delayed in the affected eyes (P =.0089, Wilcoxon signed rank test). CONCLUSIONS: Because the peripheral retina contributes more significantly to full-field ERGs than the macula, the reduced OP amplitudes of the full-field ERGs in eyes with aphakic or pseudophakic CME suggest a functional impairment not only in the macula but also throughout the retina.

Aged↗
PubMed2003

Foveal thickness in occult macular dystrophy.

PURPOSE: Occult macular dystrophy (OMD) is an inherited macular dystrophy characterized by a progressive macular dysfunction without any visible fundus abnormality. We studied the foveal thickness in patients with OMD using optical coherence tomography (OCT). DESIGN: Observational case series. Foveal thickness by OCT images. METHODS: Foveal thickness obtained from 22 eyes of 11 patients with OMD was compared with that from 27 eyes of 20 age-matched normal controls. RESULTS: Mean foveal thickness in the patients group (96.5 +/- 19.5 microm) was significantly thinner than that in the normal controls (133.3 +/- 9.0 microm, P <.0001, Mann-Whitney U test). Eighteen of 22 eyes with OMD had foveal thickness that were thinner than the lower limit of the normal range. There was no statistically significant correlation between the foveal thickness and visual acuity, age, or duration from onset. CONCLUSION: These results demonstrated that there are significant anatomic changes in the macula of patients with OMD.

Adolescent↗
PubMed2003

Macular dystrophy in a Japanese family with fundus albipunctatus.

PURPOSE: To report a Japanese family with fundus albipunctatus and macular dystrophy associated with a mutation in the 11-cis retinol dehydrogenase (RDH5) gene. DESIGN: Observational case report. METHOD: Ophthalmic examinations and DNA analysis were performed. RESULTS: The fundi of a 56-year-old man and his 51-year-old sister showed numerous yellow-white punctata. He also had bull's-eye maculopathy and prepappillary arterial loops, whereas she did not, and his best-corrected visual acuity was impaired, whereas hers was normal. Their kinetic visual fields did, however, show central or paracentral scotoma, and both had tritanomalous color vision. Their scotopic electroretinograms were typical of fundus albipunctatus, and photopic electroretinograms were significantly reduced. A homozygous Gly107Arg mutation in the RDH5 gene was detected in both siblings. CONCLUSIONS: We suggest that the macular dystrophy is caused by the RDH5 gene mutation as a phenotype variation in fundus albipunctatus.

Alcohol Oxidoreductases↗
PubMed2003

Optical coherence tomography and focal macular electroretinogram in eyes with epiretinal membrane and macular pseudohole.

PURPOSE: To determine the morphology of macular pseudoholes (MPHs) and the relationship of morphology to macular function. DESIGN: Observational case series. METHODS: Optical coherence tomography (OCT) was performed on 42 eyes of 42 consecutive patients with an epiretinal membrane (ERM) and an MPH. The diameters of the MPH, and the thickness of the foveal and parafoveal retina were measured. Of these 42 eyes, focal macular electroretinograms (FMERGs) were recorded from 22 eyes of 22 patients with a 15 degree stimulus; FMERGs were also recorded with a 5 degree stimulus from 9 eyes of these 22 eyes. RESULTS: In 42 eyes, the mean +/- Standard deviation (SD) diameter (437.7 +/- 172.8 microm) and geometrical shape of the MPHs were not significantly correlated with the visual acuity. The MPHs were divided into 2 types from the OCT images at the base of MPHs; group A had normal thickness (100-199 microm; n = 29), and group B (n = 13) had thicknesses of >or= 200 microm, or thickness < 100 microm, or irregular base. The visual acuity in group A (logarithm of the minimum angle of resolution [log MAR] mean +/- SD:.083 +/-.144) was significantly better than group B (log MAR,.407 +/-.212, P <.0001). There was a significant reduction in the amplitude of all components of FMERGs elicited by the 15 degree stimulus in the affected eyes (mean +/- SE, A-wave: 1.26 +/-.12 microv, B-wave: 3.07 +/-.27 microv, oscillatory potentials: 1.23 +/-.25 microv) compared with the normal fellow eyes (A-wave: 1.58 +/-.13 microv, B-wave: 4.14 +/-.27 microv, oscillatory potentials: 2.35 +/-.29 microv). A significant correlation was found between the relative amplitudes of the B-wave elicited by the 5 degree stimulus and the visual acuity (r =.918, P =.0005). CONCLUSIONS: In eyes with an ERM and an MPH, the visual acuity is generally correlated with the OCT images. Macular function of eyes with an MPH resembles eyes with an ERM without an MPH. The effect of the ERM appears to be different on the base and parafovea of the MPHs.

Adult↗
PubMed2003

Morphologic and angiographic assessment of the macula after macular translocation surgery with 360 degrees retinotomy.

PURPOSE: To compare the optical coherence tomographic assessment of retinal thickness and the fluorescein angiographic appearance after macular translocation surgery for subfoveal choroidal neovascularization. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Twenty-three consecutive eyes. INTERVENTION AND TESTING: Optical coherence tomography and fluorescein angiography were performed before and 6 to 15 months (mean +/- standard error [SE], 10.4+/-0.7) after macular translocation surgery with a 360 degrees retinotomy in 23 patients, ages 48 to 79 years, with age-related macular degeneration (12 eyes), polypoidal choroidal vasculopathy (2 eyes), and high myopia (9 eyes). The diameter of the choroidal neovascularizations ranged from 0.3 to 2.6 disc diameters (mean +/- SE, 1.2+/-0.2), and the angle of rotation of the retina ranged from 11 degrees to 45 degrees (mean +/- SE, 29.1+/-2.1 degrees ). RESULTS: The preoperative best-corrected visual acuity ranged from hand motions to 20/100, and the postoperative best-corrected visual acuity ranged from 20/667 to 20/25. Optical coherence tomography demonstrated a concave foveal configuration after surgery in all 23 eyes, with a mean foveal thickness of 150+/-11 micro m (mean +/- SE). Fluorescein angiography showed various degrees of fluorescein leakage with a pattern similar to cystoid macular edema in 16 of 23 eyes (70%). CONCLUSIONS: The newly located macula after macular translocation surgery with a 360 degrees retinotomy had cystoid macular edema on fluorescein angiography and normal macular configuration with normal thickness in optical coherence tomography.

Aged↗
PubMed2003

RDH5 gene mutations and electroretinogram in fundus albipunctatus with or without macular dystrophy: RDH5 mutations and ERG in fundus albipunctatus.

The aim of this study was to analyze the RDH5 gene in patients with fundus albipunctatus with and without macular dystrophy, and correlate the identified mutations with the electrophysiological results. Twenty-one patients from 19 unrelated Japanese families with fundus albipunctatus were examined. Ten unrelated patients had macular dystrophy. In 18 patients, either a homozygous or a compound heterozygous mutation in the RDH5 gene was identified. The bright-flash, mixed rod-cone ERG had a negative configuration with reduced a-wave amplitudes after a short period of dark-adaptation (20 or 30 min). After a prolonged dark-adaptation period (2 or 3 h), the waveform attained normal amplitudes in patients without macular dystrophy but the a-waves were still subnormal in patients with macular dystrophy. The photopic ERG responses were significantly reduced in patients with macular dystrophy, indicating that they also had cone dystrophy. The photopic ERGs were reduced in only some of the patients without macular dystrophy. In patients without macular dystrophy, the scotopic b-wave amplitudes were nonrecordable or significantly reduced after a short dark-adaptation period but then improved to normal levels. However, they did not fully recover in some patients with macular dystrophy. Three patients with macular dystrophy in whom a RDH5 gene mutation could not be detected by our routine method had atypical ERG responses. We conclude that RDH5 gene mutations cause a progressive cone dystrophy or macular dystrophy as well as night blindness. The clinical phenotype including electrophysiological responses varied among patients with the RDH5 gene mutations.

Adolescent↗
PubMed2003

Functional rescue of N-methyl-N-nitrosourea-induced retinopathy by nicotinamide in Sprague-Dawley rats.

PURPOSE: A single intraperitoneal injection of 60 mg/kg body weight of N-methyl-N-nitrosourea (MNU) into rats results in retinal degeneration over a 7-day period in all treated animals. The purpose of this study was to determine whether nicotinamide (NAM) can lead to a functional rescue of the MNU-induced retinopathy. METHODS: NAM, a water-soluble B-group vitamin (vitamin B( 3)), was administered immediately after MNU injection, and retinas were examined morphologically and functionally. RESULTS: Morphologically, 1000 mg/kg NAM completely suppressed and 50 mg/kg NAM partially suppressed the photoreceptor cell loss. Functionally, scotopic and photopic electroretinographic (ERG) recordings showed that both rod and cone photoreceptor cells were well protected from MNU damage by 1000 mg/kg NAM and partially protected by 50 mg/kg NAM. CONCLUSIONS: NAM can protect photoreceptor cells from MNU-induced retinopathy both structurally and functionally.

Alkylating Agents↗
PubMed2003

Function and morphology of macula before and after removal of idiopathic epiretinal membrane.

PURPOSE: To study the function and morphology of the macula of the eye before and after the removal of unilateral idiopathic epiretinal membrane (ERM). METHODS: Focal macular electroretinograms (fmERGs) elicited by a 15 degrees stimulus were recorded in 37 eyes of 37 patients with a unilateral ERM. The amplitudes of the a- and b-waves and the oscillatory potentials (OPs) were compared with the corresponding waves in the normal fellow eyes before and after removal of the ERM. In 29 eyes followed up for more than 6 months after surgery, the fmERGs and foveal and parafoveal thicknesses, measured by optical coherence tomography (OCT), were evaluated. RESULTS: Before surgery, the mean amplitudes of all components of the fmERGs were significantly smaller than in the fellow eyes, with the decrease largest for the OPs, followed by the b-waves and then the a-waves. The eyes with less severely reduced a-wave amplitude (>70% of the fellow eyes) had significantly lower b-wave to a-wave (b/a) ratios. After surgery, the amplitudes of the b-wave and OPs were still significantly smaller in the affected eyes. The mean foveal and parafoveal thicknesses were significantly less after surgery; however, the thickness was still more in the affected eyes. The decrease of the OPs remained after surgery and correlated with increased parafoveal thickness (r = -0.460, P = 0.011). CONCLUSIONS: The decreased fmERGs indicate that macular function is impaired in eyes with ERM. The decrease of the b-wave and OPs in the 29 eyes examined after vitrectomy may be due to the still thickened macular retina.

Aged↗
PubMed2003

Multifocal electroretinograms in X-linked retinoschisis.

PURPOSE: To study local retinal cone function in patients with X-linked retinoschisis (XLRS) by multifocal ERGs (mfERGs). METHODS: mfERGs were recorded from seven eyes of seven patients with XLRS (mean age +/- SD, 22.1 +/- 3.2 years; range, 18 to 25 years). Five eyes had microcystic changes in the macula and two eyes had nonspecific macular degeneration. Two eyes had peripheral retinoschisis, and some of the stimuli fell on this area. The stimulus array consisted of 103 hexagons and the total recording time was set at approximately 4 minutes. The amplitudes and implicit times of both focal and summed responses for the first- and second-order kernels were analyzed. RESULTS: The amplitudes of the first-order kernel were markedly reduced in the central retina in all eyes. A large variation was observed in the amplitudes outside the fovea. The amplitudes of the focal cone ERGs at the peripheral retinoschisis did not differ from those recorded from adjacent retinal loci without the retinoschisis. The implicit times of the first-order kernel were significantly delayed, and the amplitudes of the second-order kernels were more affected than the first-order kernels across the whole field in all XLRS eyes. CONCLUSIONS: The cone-mediated retinal responses were more impaired in the central than peripheral retina in eyes with XLRS. Delayed implicit times of the first-order kernel and reduced second-order kernel across the whole testing field in all XLRS eyes suggest that there is widespread cone-system dysfunction in XLRS.

Adolescent↗
PubMed2003

Changes in focal macular electroretinograms and foveal thickness after vitrectomy for diabetic macular edema.

PURPOSE: To evaluate the changes in the focal macular electroretinogram (FMERG) and foveal retinal thickness after vitrectomy for diabetic macular edema (DME). METHODS: FMERGs were elicited from 25 eyes of 21 patients (ages 29-75 years) who underwent vitrectomy for DME by a 15 degrees stimulus. A posterior vitreous detachment (PVD) was created during surgery in 19 eyes (group 1), and 4 eyes had a PVD before surgery (group 2). In the remaining 2 eyes, a PVD could not be created (group 3). FMERGs were recorded before and 3, 6, and 12 months after vitrectomy. The foveal thickness, determined by optical coherence tomography (OCT), and visual acuity were measured on the same day as the FMERG recordings. RESULTS: The postoperative visual acuity (logarithm of the minimum angle of resolution [logMAR]) improved gradually after the surgery and was significantly better at 12 months in eyes in group 1 (P = 0.0393). The postoperative mean foveal thickness was significantly less at 3 months after surgery in group 1 eyes (P = 0.0006), and there was a further decrease thereafter. In the 2 eyes in group 3, the decreased foveal thickness 3 and 6 months after surgery became thicker at 12 months. The mean b-wave amplitude of the FMERGs increased significantly at 12 months in group 1 eyes (P = 0.0297). The mean implicit time of a- and b-waves was more delayed at 3 months, and the change in a-wave was statistically significant in group 1 eyes (P = 0.0474). There was a wide range of changes in the b-wave amplitude at 12 months, however, the increase in the b-wave was correlated with the decrease in foveal thickness (r =.49, P = 0.012). CONCLUSIONS: A disparity in the time course and degree of recovery of the foveal thickness and macular retinal function was found in eyes with DME after vitrectomy. Part of the functional recovery could be attributed to decreased retinal thickness and the absorption of the subretinal fluid.

Adult↗
PubMed2003

Stereopsis in idiopathic macular hole with special reference to the size of the hole and its effect on stereoacuity.

PURPOSE: To identify the characteristics of binocular vision in unilateral idiopathic macular hole (MH) regarding the size of the hole and its effect on stereopsis. SUBJECTS AND METHODS: Twelve patients with idiopathic MH were tested using the Amsler Grid, Bagolini Striated Glasses, Starlight Test, Titmus Stereotest (the Titmus) and Lang Stereotest (the Lang). The results were analyzed with reference to two parameters: visual acuity and the size of the MH. RESULTS: The size of the MH in 12 subjects ranged from 0.67 degrees to 2.13 degrees (mean, 1.29 degrees). The MHs caused distorted central vision under binocular conditions. Visual acuities ranged from 0.3 to 0.06. Nine out of the 12 patients (75%) failed the 800 seconds of arc (") with the Titmus, but all 12 patients (100%) demonstrated stereoacuity of 550" to 600" with the Lang. CONCLUSION: The discrepancy of measured stereoacuity between the Titmus and the Lang was hypothesized to be due to the different size of the test charts and their targets and the pattern of the visual deficit. The pass rate of 92% (550") with the Lang is better than rates for other patients with higher visual acuities, such as children with amblyopia (62-70%) or adults undergoing visual screening (67%). In cases of MH, intact overlapped visual field beyond the central 0-2 degrees played an important role in maintaining stereoscopic vision.

Aged↗
PubMed2002

Macular dystrophy in a 9-year-old boy with fundus albipunctatus.

PURPOSE: To report a 9-year-old boy with fundus albipunctatus and macular dystrophy. DESIGN: Observational case report. METHODS: A complete ophthalmic examination was performed. The 11-cis retinol dehydrogenase gene (RDH5) was examined by direct genomic sequencing. RESULTS: The fundi of the 9-year-old boy showed numerous yellow-white punctata as well as foveal atrophic lesions in both eyes. His corrected visual acuity was RE: 0.5 and LE: 0.3. Scotopic full-field electroretinograms were not present after 20 minutes of dark-adaptation but were normal after 3 hours of dark-adaptation. Full-field cone and 30-Hz flicker electroretinograms were normal; however, focal macular cone electroretinograms were significantly reduced. A compound heterozygous mutation of Tyr281His and Leu310GluVal in RDH5 was detected. CONCLUSION: We suggest that the macular dystrophy is caused by the RDH5 mutation as a phenotype variation in fundus albipunctatus.

Alcohol Oxidoreductases↗
PubMed2002

Enhanced S-cone syndrome with subfoveal neovascularization.

PURPOSE: To report a case of enhanced S-cone syndrome associated with subfoveal neovascularization. DESIGN: Observational case report. METHODS: A 23-year-old man, who was first examined at age 9 years, was found to have enhanced S-cone syndrome by clinical, electrophysiological, and molecular genetic examinations. RESULTS: At 9 years of age, a subfoveal neovascularization was present in his right eye and corrected visual acuity was RE: 0.15 and LE: 1.0. After he was 20 years old, cystoid changes in the macula of the left eye appeared and visual acuity, in the left eye, decreased from 1.0 to 0.02. CONCLUSION: The clinical course of enhanced S-cone syndrome is progressive, and we suggest that the subretinal neovascularization is a phenotypic variation of enhanced S-cone syndrome.

Adult↗