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Biomedical subjects

L Z Wu

Publications and source records attributed to L Z Wu.

At least 19 recordsLinked to original sources
PubMed1992

[A study on sexual differences of postero-anterior cephalometrics among Chinese in Taiwan with different occlusions].

The main purpose of this study is to investigate the characteristics of cranio-dento-facial morphology among Chinese in Taiwan with different occlusions by the postero-anterior cephalograms and to examine the differences between sexes in the cranio-dento-facial width as well as morphology. Our study comprised three hundred and seventy three patients with preorthodontic treatment records. They were divided into 12 groups with respect to the Angle's classification, sex, and age. Summarizing the differences of the various cephalometric analyses, 31 kinds of measurement, including 20 values of width dimension and 11 values of the width ratio, were employed. The results of using the Student t-test to study the sex differences of cranio-dento-facial width and morphology are summarized as follows: (1) The sexual dimorphism of the cranio-dento-facial width occurs as early as the age of 9-12. The deviation is augmented continuously with growth and, hence, it is more pronounced in adults. (2) Regardless of the class of occlusion or the stage of maturity, the cranio-dento-facial size of the male is significantly larger than that of the female. However, their cranio-dento-facial morphology is similar. (3) The sexual dimorphism of the cranio-dento-facial width dimensions is most pronounced in the zygoma, the mandibular angle and the condyles.

Adult↗
PubMed1991

[The characteristic electroretinogram anomalies in age-related macular degeneration].

The color stimulated electroretinogram (ERG) was found abnormal in 104 eyes of 64 cases of age-related macular degeneration (AMD). The number of a-wave troughs with dark adapted red stimulation decreased in 69 eyes, of which 27 eyes also showed diminished a- and b-waves under dark and light adaptation. Among the remaining 35 eyes that demonstrated no decrease in the number of a-wave troughs, there were 6 eyes with a- and b-wave diminution under dark and light adaptation. The findings indicated that the ERG anomalies in AMD were detected more readily with dark adapted red stimulation, particularly evident in the wet type of AMD, thus conducive to the judgement of visual impairment and prognosis.

Age Factors↗
PubMed1990

Model parameters of the smooth pursuit eye movement system with electrooculogram.

The visual pursuit test is a method that collects and analyzes the characteristics of pursuit eye movements and examines the function of the eye movement system. This paper analyzes the model parameters of the smooth pursuit eye movement system in order to explore a method for improving the analysis. The input-output relationship of the smooth pursuit system can be expressed by a quasilinear model. We compute the model parameters (gain, phase, spectral purity, cross covariance) by digital signal processing. Eye movement is recorded by electrooculogram. Both eyes are tested individually. The visual target moves at frequencies of 0.2, 0.4, 0.8, 1.2, and 1.6 Hz. Ranges are gain, 1.01 to 0.70; phase, -0.1 degree to -66 degrees; spectral purity, 0.97 to 0.70; and cross covariance, 0.99 to 0.26. We tested 40 normal subjects as well as patients with ataxia (8), vertigo (18), and ophthalmoplegia (9). The oculomotor system of normal subjects functions as a linear system in the performance of this test at 0.2 to 0.8 Hz. The spectral purity dropped to about 0.70 at 1.6 Hz. The variability of all measures increases greatly at 1.6 Hz, which indicates that this target motion exceeds the tracking ability of many normal subjects and that the oculomotor system of normal subjects functions as a nonlinear system in this condition. Statistical tests show no significant differences between sex, age, and the two eyes. The model parameters tentatively proved effective in clinical application.

Adolescent↗
PubMed1990

Objective measurement of contrast sensitivity using the steady-state visual evoked potential.

Contrast sensitivity functions (CSFs) were determined electrophysiologically with the steady-state visual evoked potential (VEP). Psychophysical CSFs obtained by the method of increasing contrasts were also measured concurrently with the VEP trials. The VEP contrast thresholds were obtained using a rapid recording technique in which the contrast of a counterphase sinewave modulated at a temporal frequency of 7.5 Hz was swept from 0.5% to 40% over a period of 22 s in 39 equal logarithmic steps. For this pattern reversal stimulus, the amplitude and phase of the second harmonic response as a function of contrast were measured using a discrete Fourier transform (DFT). Contrast sensitivities at five spatial frequencies ranging from 0.5 to 14.9 cpd were measured. The VEP contrast thresholds were determined by a linear extrapolation to zero amplitude. The contrast threshold obtained by the two methods correlated at 0.816 for 14 subjects. For all five spatial frequencies there were no significant differences between the contrast sensitivities derived from the two methods.

Adult↗
PubMed1989

The electroretinogram in Marfan's syndrome.

Marfan's syndrome (MS) is an inherited disease of connective tissue. The most characteristic ocular change is dislocation of lens, but myopia and retinal detachment also can occur. We examined 11 MS patients using electroretinography (ERG). 6 cases showed normal ERG. 5 cases had abnormal ERG. One had retinal detachment. 3 had myopia and 1 case suffered from secondary glaucoma. The defects of visual function were shown by electrophysiological test in those MS patients.

Adolescent↗
PubMed1989

Clinical study of low vision. Part I: Refraction and the aided distance vision.

Eighty three cases of low vision patients (144 eyes) were examined with distant visual aids. The average visual acuity of the 144 eyes before refraction was approximately 0.07, while the counterpart afterwards was about 0.1 (p less than 0.01). With the 4x monocular focusable aid, acuity improved in 142 eyes out of the 144 eyes. The combined use of clip-on distance aid and the spectacle reading aid was observed to be especially suitable for partially sighted students. The mean MEF of 142 eyes was 0.9435 +/- 0.2068. The paired T-test between the difference of actual magnification and theoretical magnification was not significant at the 5% level. The factors contributing to the variance of MEF were discussed.

Adolescent↗
PubMed1989

Visual field versus visual evoked potentials in maculopathies and optic neuropathies.

Both kinetic and static visual fields and visual evoked potential (VEP) were tested in 52 patients with maculopathies and in 29 patients with axial optic neuropathies. The results of central static quantitative perimetry and pattern reversal VEP were compared. The amplitude and latency of P100 were correlated with the total loss of central visual threshold in maculopathies. While the P100 latency was not correlated with the total loss of the central visual threshold in neuropathies, their latency delay was more obvious than that in maculopathies. We arrived at the conclusion that both VEP and visual field are necessary for assessing function loss and reflecting different pathological mechanisms in macular and optic nerve diseases.

Adolescent↗
PubMed1989

[Early abnormalities of visual functions in aging macular degeneration].

Visual functions in aging macular degeneration were observed by contrast sensitivity, color vision (FM 100-hue, Panel D-15), visual field (dynamic perimetry, suprathreshold static perimetry and static perimetry profile), with simultaneous recordings of pattern electroretinogram and pattern evoked potential. The results showed that even in AMD eyes with normal visual acuity, 34.0-79.1% had abnormal visual psychophysical function or electrophysiological measurements, suggesting that many abnormalities in visual function appeared in early AMD. The factors of abnormal early visual function changes in AMD were discussed.

Aging↗
PubMed1989

[Study of aging macular degeneration].

Aging macular degeneration (AMD) is an important ocular disease causing blind. The study of epidemiology, pathogenetic factors and visual function of AMD show that it has become a disease worth noticing in aged. Although most AMD cases were of the dry type and the patients had rather good visual acuity, various determination of visual function showed different degrees of impairment. Controlling light exposure and improving trace element metabolism may be helpful for early prevention and treatment of AMD. It will also be an important factor in the prevention of blindness in Asian nations.

Aged↗
PubMed1988

Hereditary characteristics of enzyme deficiency and dermatoglyphics in congenital color blindness.

The hereditary characteristics of enzyme deficiency and dermatoglyphics in congenital color blindness (CCB) were studied. We propose that there is a linkage between the two loci on the X-chromosome determining CCB and glucose-6-phosphate dehydrogenase (G6PD), based on our study of a high incidence of G6PD deficiency in 156 male cases with CCB. The CCB gene is closely linked with that of G6PD deficiency from our pedigree investigations. The rise in the frequency of eight or more whorls, the low value of atd angle and the presenting rate of real palmar patterns of the thenar, hypothenar and I, areas presented the hereditary traits of congenital color blindness.

Color Vision Defects↗