Biomedical subjects

Eiichi Yukawa

Publications and source records attributed to Eiichi Yukawa.

14 recordsLinked to original sources

PubMed2006

Frequency doubling technology perimetry after clear and yellow intraocular lens implantation.

PURPOSE: To evaluate the effect of intraocular lens (IOL) color on frequency doubling technology (FDT). DESIGN: Randomized clinical trial. METHODS: For 26 eyes of 26 patients, FDT perimetry (24-2-threshold test) was measured three months after cataract surgery. An acrylic IOL was randomly selected from clear (VA60BB, HOYA) and yellow-tinted lenses (YA60BB, HOYA), which only differed by color. As a control, a further 14 cataractous eyes with visual acuity > or =20/30 were examined. We analyzed mean deviation (MD) and pattern standard deviation (PSD) among the three groups. RESULTS: After cataract surgery, MD significantly improved (Fisher protected least significant difference (PLSD): P < .05), but PSD did not change (analysis of variance (ANOVA): P = .94) compared with control values. There was no significant difference between the two IOLs for either MD (Mann-Whitney test; P = .15) or PSD (Mann-Whitney test; P = .84). CONCLUSIONS: When interpreting the results of FDT, the effect of cataract should be considered but that of IOL color does not need consideration.

Color↗

PubMed2006

Pattern-reversal visual evoked potentials in patients with human T-lymphotropic virus type 1 uveitis.

PURPOSE: The purpose of this study was to evaluate the possible injury in the optic pathway by measuring P100 peak latency of pattern-reversal visual evoked potentials (PVEPs) in patients with human T-lymphotropic virus type 1 uveitis (HU). METHODS: The P100 peak latency of PVEP was measured during the period without macular abnormalities observed by fluorescein angiography in 23 patients (46 eyes) with HU and 24 patients (48 eyes) with Vogt-Koyanagi-Harada disease (VKH) with a corrected visual acuity of 20/25 or more. To determine the normal upper limit of P100 peak latency, PVEPs were measured in 31 normal subjects (31 eyes). In addition, in the HU patients, the serum anti-HTLV-1 antibody titer was measured by particle agglutination assay within 3 months of PVEP recording, and the period of HU was retrospectively surveyed. RESULTS: Delayed latency was observed in 4 (7 eyes) of the 23 patients (46 eyes) with HU but none of the 24 patients (48 eyes) with VKH. All four patients with delayed latency showed a serum anti-HTLV-1 antibody titer of more than x4000. The HU period in the HU patients was 0.2-14.0 years, and the HU periods in the four patients with delayed latency were 0.8, 2.7, 4.2, and 14.0 years, respectively. CONCLUSIONS: We measured pattern-reversal visual evoked potentials and observed delayed P100 peak latency in 7 of the 46 eyes in 4 (17.4%) of the 23 HU patients. This suggests injury in the optic pathway including the optic nerve by HTLV-1 in some patients with HU. In the future, consideration should also be given to the possible development of optic neuropathy due to HTLV-1.

Adolescent↗

PubMed2006

Traumatic optic neuropathy caused by blunt injury to the inferior orbital rim.

A 48-year-old woman was struck on the right inferior orbital rim by a gardening device and immediately developed complete visual loss in the right eye. Clinical and imaging evaluations failed to disclose any damage to the globe or optic nerve or to their nearby soft tissues and bones. Within months, ipsilateral optic disc pallor, a nerve fiber bundle visual field defect, and a persistently subnormal visual acuity developed. We attribute the visual loss to indirect optic nerve injury. To our knowledge, blunt injury to the inferior orbital rim has not been reported as a cause of this phenomenon.

Eye Injuries↗

PubMed2006

Effect of static visual acuity on dynamic visual acuity: a pilot study.

The aim of this pilot study was to evaluate whether dynamic visual acuity changes with or without refractive correction. 42 healthy enrolled subjects with normal vision were divided into two age-matched groups. In Group A, dynamic visual acuity was measured first with the refractive error fully corrected and then without. In Group B, dynamic visual acuity measurements were taken in the reverse order of that performed by Group A. The measurements were binocularly performed five times using free-head viewing after dynamic visual acuity values were stable. Significant changes in dynamic visual acuity (static visual acuity 20/20 vs 12/20) were observed in both Group A (171.6 +/- 36.0 deg./sec. vs 151.8 +/- 39.6 deg./sec., Wilcoxon test, p < .001) and Group B (169.8 +/- 30.0 deg./sec. vs 151.2 +/- 36.0 deg./sec., Wilcoxon test, p < .001). The interaction was significant (F1.20 = 8.12, p = .009). These results indicated that refractive correction affected dynamic visual acuity.

Adult↗

PubMed2006

Use of multifocal visual evoked potential tests in the objective evaluation of the visual field in pediatric epilepsy surgery.

OBJECT: To evaluate objectively the visual fields of patients with pediatric epilepsy who are uncooperative with perimetry and in whom postoperative visual field deficits are expected, the authors investigated the usefulness of the multifocal visual evoked potential (VEP) method. METHODS: Normal waves in multifocal VEP were determined in 21 healthy children (21 eyes) 6 to 15 years of age (mean 11.4 years). Responses from eight sites in each child were divided into four quadrants (superior and inferior temporal and superior and inferior nasal). In each quadrant, two response waves were grouped and averaged. The peak latency and amplitude at approximately 100 msec were used for assessment. In three cases involving patients with epilepsy, multifocal VEP measurements were also recorded and compared with the peak latency and amplitude in the healthy children. In these children, no significant differences were observed in the peak latency of amplitude among four quadrants using one-way analysis of variance. In each patient, multifocal VEP tests showed abnormal waves in the quadrant corresponding to the lesion demonstrated in neuroradiological images. This result was useful in the treatment of choice and the postoperative evaluation. CONCLUSIONS: Multifocal VEP tests can be useful in evaluating the visual field of children objectively. They can also be valuable in assessing preoperative visual field defects and revealing changes in the visual field after treatment.

Adolescent↗

PubMed2006

[Clinical application of multifocal visual evoked potentials in children with epilepsy caused by intracranial disease].

PURPOSE: We investigated whether visual field defects could be objectively evaluated using multifocal visual evoked potential(m-VEP) in two children with epilepsy caused by intracranial disease in whom it was difficult to measure the visual field. METHODS: To determine normal waves in m-VEP, recording was performed using a visual evoked response imaging system(VERIS)Junior Science program (Mayo, Aichi, Japan) in 20 healthy children (20 eyes); peak latency and amplitude were used for assessment. In the two children with epilepsy, m-VEPs were recorded, and compared with the results of static perimetry or the lesions observed by Magnetic Resonance Imaging (MRI). RESULTS: In the 20 healthy children, there was no significant difference in the peak latency or amplitude among 4 quadrants by one-way analysis of variance. m-VEP in the children with epilepsy showed abnormal waves, corresponding to the visual field defects in the static perimetry or the lesions observed by MRI. CONCLUSIONS: Objective evaluation of visual field defects using m-VEP may be useful in children with epilepsy caused by intracranial disease in whom kinetic/static perimetry as a subjective examination is difficult.

Brain Diseases↗

PubMed2006

[Objective evaluation of the visual field defects in a patient with cerebral infarction using multifocal VEPs].

PURPOSE: We investigated whether visual field defects can be objectively evaluated using multifocal visual evoked potentials (mVEP) in a patient with cerebral infarction in whom it is difficult to measure the visual field. METHODS: To determine normal waves in mVEP recording was performed using a VERIS Junior Science (Mayo, Aichi, Japan) in 20 healthy subjects (20 eyes), peak latency and amplitude were used for assessment. In a patient with cerebral infarction, mVEP were recorded, and compared with the lesion observed by computed tomography. RESULTS: In 20 healthy subjects, the waveforms in the nasal and temporal quadrants were very similar but the waveforms in the superior and inferior quadrants were mirror images. The mVEP in patient with cerebral infarction showed abnormal waves, corresponding to the visual field defects in the lesion observed by computed tomography. CONCLUSIONS: Objective evaluation of visual field defects using mVEP may be useful in patients with cerebral infarction in whom kinetic/static perimetry as a subjective examination is difficult.

Aged↗

PubMed2005

Influence of intraocular lens optical design on high-order aberrations.

PURPOSE: To compare differences in high-order aberrations (HOAs) between 2 intraocular lens (IOL) optical designs. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHOD: Sixty eyes that had uncomplicated phacoemulsification and IOL implantation were assigned to 1 of 2 groups based on the type of IOL optical design: more posteriorly curved biconvex shape (AcrySof MA30BA, Alcon) (n=30 eyes) or more anteriorly curved biconvex shape (AcrySof MA30AC) (n=30 eyes). All patients had best corrected visual acuity better than 20/25. High-order aberrations were measured using a Hartmann-Shack aberrometer at 4.0 mm and 6.0 mm wavefront aperture diameters. RESULTS: At 4.0 mm aperture diameters, there were no differences between the 2 groups in HOAs (P>.05, Mann-Whitney U test) in the cornea and the whole eye. At 6.0 mm aperture diameters, MA30AC eyes had a smaller amount of spherical-like aberrations (P=.043) than MA30BA eyes; however, there were no significant differences between the 2 groups in coma-like aberrations and total aberrations in the whole eye (P>.05). At 6.0 mm aperture diameters, there were no differences between the 2 groups HOAs in the cornea. (P>.05). CONCLUSION: The optical design of the spherical IOL influenced the spherical-like aberrations in the whole eye. This may reduce retinal image quality.

Acrylic Resins↗

PubMed2005

Effect of tilt of 2 acrylic intraocular lenses on high-order aberrations.

PURPOSE: To investigate the high-order aberrations (HoAs) in pseudophakia between 2 foldable acrylic intraocular lenses (IOL) with differences in the tilt of IOL. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHOD: Sixty-four eyes that had uncomplicated phacoemulsification and IOL implantation were assigned to 1 of 2 groups: Acryfold 60BB (HOYA [n=30 eyes]) and AcrySof MA60AC (Alcon [n=34 eyes]). All patients had best corrected visual acuity better than 20/25. High-order aberrations were measured using the Hartmann-Shack aberrometer at 4.0 mm and 6.0 mm wavefront aperture diameters, and the IOL tilt and decentration were measured using Scheimpflug videophotography. RESULTS: There was a significant difference in the IOL tilt (60BB=2.22 degrees +/- 1.44 (SD), 60AC=3.18 +/- 1.84 degrees; P=.041, Mann-Whitney U test), but no difference in IOL decentration (P>.05). In the cornea, there were no differences between the 2 groups in HoAs at 4.0 mm and 6.0 mm aperture diameters (P>.05, Mann-Whitney U test). In the whole eye, there was no difference between the 2 groups in spherical-like aberrations, coma-like aberrations, and total aberrations at the 4.0 mm and 6.0 mm aperture diameters (P>.05). The compensation of the internal optics with the 60BB group was better than with the 60AC group for coma-like (P=.037) and total aberrations (P=.010) at 6.0 mm aperture diameter. CONCLUSION: The smaller tilt of the IOL induced more compensation for the coma-like and total aberrations at the 6.0 mm aperture diameter. The IOL tilt should be small, especially in a large pupil, with regard to HoAs.

Aberrometry↗

PubMed2005

A child with epilepsy in whom multifocal VEPs facilitated the objective measurement of the visual field.

PURPOSE: We investigated whether visual field defects can be objectively evaluated by using multifocal visual evoked potential (multifocal VEP) in children with epilepsy in whom it is difficult to measure the visual field. METHODS: First, to determine normal waves in multifocal VEP, recording was performed by using a VERIS Junior Science (Mayo, Aichi, Japan) in 21 healthy children (21 eyes) consisting of 12 boys and nine girls aged 6 to 15 years (mean age, 11.4 years). Responses from eight sites in each subject were divided into four quadrants (superior and inferior temporal quadrants and superior and inferior nasal quadrants). In each quadrant, two response waves were grouped and averaged; peak latency and amplitude were used for assessment. In a child with epilepsy in whom kinetic or static perimetry was impossible, multifocal VEPs were recorded and compared with the peak latency and amplitude in the healthy subjects. RESULTS: In the 21 healthy children, no significant differences were observed in the peak latency or amplitude among four quadrants by one-way analysis of variance. Multifocal VEPs in the child with epilepsy showed abnormal waves in the right hemivisual field, which corresponded to the lesion observed with magnetic resonance imaging. CONCLUSIONS: The objective evaluation of visual field defects by using multifocal VEP may be useful in children with epilepsy in whom kinetic/static perimetry as a subjective examination is difficult.

Adolescent↗

PubMed2004

High-order aberrations with Hydroview H60M and AcrySof MA30BA intraocular lenses: comparative study.

PURPOSE: To compare differences in high-order aberrations between 2 intraocular lenses (IOLs), the Hydroview H60M (Bausch & Lomb) and AcrySof MA30BA (Alcon). SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHOD: Twenty-four eyes of 14 patients with a Hydroview IOL and 25 eyes of 20 patients with an AcrySof IOL who had uneventful phacoemulsification and a best corrected visual acuity better than 20/16 from 6 to 12 months after surgery were evaluated. High-order aberrations were measured using a Hartmann-Shack aberrometer at 4.0 mm and 6.0 mm wavefront aperture diameters, and IOL tilt and decentration were assessed by Scheimpflug videophotography. RESULTS: There were no differences between the 2 groups in IOL tilt and decentration (P>.05, Mann-Whitney U test). In the cornea, there were no differences between the 2 groups in high-order aberrations at 4.0 mm and 6.0 mm aperture diameters (P>.05, Mann-Whitney U test). In the whole eye, there was a significant difference between Hydroview (mean 0.441 microm +/- 0.147 [SD]) and AcrySof (0.696 +/- 0.287 microm) IOLs in spherical-like aberrations at the 6.0 mm aperture diameter (P =.00008, Mann-Whitney U test); there were no differences between the 2 groups in other aberrations. CONCLUSIONS: The type of IOLs influenced spherical-like aberrations. The IOL's shape was a particularly important factor in spherical-like aberrations. The aberrations may affect night driving in certain individuals.

Acrylic Resins↗

PubMed2004

Influence of intraocular lens tilt and decentration on wavefront aberrations.

PURPOSE: To investigate the influence of intraocular lens (IOL) tilt and decentration on higher-order aberrations (HOAs) using wavefront analysis. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: Forty eyes of 40 patients with a 5.5 mm optic, foldable acrylic IOL were examined 4 to 48 months postoperatively. Ocular wavefront aberrations of the central 4.0 mm aperture diameter were measured using a Hartmann-Shack aberrometer. Higher-order aberrations from the 3rd to 4th order were calculated using Zernike polynomials. The relationship between IOL tilt and decentration, measured with a Scheimpflug camera, and ocular HOAs were investigated. RESULTS: The correlation between IOL tilt and coma-like aberrations was significant (r=0.431, Spearman rank correlation coefficient; P=.007). However, the correlation between IOL tilt and the spherical-like and total aberrations was not significant (P>.05), nor was the correlation between IOL decentration and coma-like, spherical-like, and total aberrations (P>.05). CONCLUSIONS: Intraocular lens tilt influenced ocular coma-like aberrations. The quality of the retinal image may improve by reducing IOL tilt.

Aged↗

PubMed2002

Indocyanine green angiography in patients with human T cell-lymphotropic virus type 1 uveitis.

PURPOSE: To determine the indocyanine green (ICG) angiographic features and to evaluate the choroidal involvement of human T-cell lymphotropic virus type 1 (HTLV-1)-associated uveitis. METHODS: We performed ICG angiography using scanning laser ophthalmoscopy in 54 eyes of 27 patients (8 men and 19 women) diagnosed with HTLV-1 uveitis. The patient's mean age was 51.5 years with a range of 24-65 years. RESULTS: The early phase of ICG angiography revealed ICG leakage from the choroidal vessels in the posterior pole, hyperfluorescent spots that which were not detected with fluorescein angiography, and small hypofluorescent lesions in the macula which most likely corresponded to microcirculatory disturbances in the choriocapillaris. CONCLUSIONS: We suggest that the ICG angiographic findings reflect choroidal lesions such as infiltration with leukocytes and edema. ICG angiography may provide useful information on choroidopathy in HTLV-1 uveitis.

Adult↗

PubMedDate not supplied

Volume phase transition of bovine vitreous body in vitro and determination of its dynamics.

The phase equilibrium property and structural and dynamical properties of bovine vitreous body was studied by macroscopic observation of swelling behavior and dynamic light scattering under various conditions. It was found that the vitreous body collapses into a compact state isotropically or anisotropically depending on the external conditions. The vitreous body collapses while maintaining the shape when the pH (</= 4) and the concentration of calcium ions (</= 1 mol/L) are changed, whereas it collapses along the orbital axis in a mixed solvent of methanol and water. From observations of the dynamics of light scattered by the vitreous body, intensity autocorrelation functions that revealed two independent diffusion coefficients, D(fast) = 7.8 +/- 1.5 x 10 (- 8) cm(2)/s and D(slow) = 3.8 +/- 0.60 x 10 (-9) cm(2)/s, were obtained. The diffusion coefficients were found to be statistically independent of position within a focal depth range of 1-1.5 mm. Divergent behavior in the measured total scattered light intensities and diffusion coefficients was observed as the concentration of calcium ion approached the critical threshold, 1 mol/L. Namely, a slowing down of the dynamic modes accompanied by increased "static" scattered intensities was observed. The divergent behavior in the scattered light intensities and diffusion coefficients was reversible. This is indicative of the occurrence of a phase transition upon calcium ion concentration.

Animals↗