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Biomedical subjects

G H van Lith

Publications and source records attributed to G H van Lith.

At least 19 recordsLinked to original sources
PubMed1987

Visual function and pattern visual evoked response in optic neuritis.

The disparity between clinical visual function and pattern visual evoked response (VER) was studied in 53 patients who had suffered an attack of optic neuritis (ON) more than six months before. The visual functions tested included Snellen visual acuity, colour vision, visual field, and contrast sensitivity. The effect of pattern presentation, check size, and luminance was tested by recording VERs with several stimulus configurations. VER amplitudes were found to be associated with the outcome of all four clinical tests, independently of check size, luminance, or the presentation method used. On the other hand VER latencies were hardly ever related to the results of any of the four clinical visual tests. These findings support the idea that VER amplitude provides information about visual spatial perception, while VER latency is more related to the extent of demyelination.

Adolescent↗
PubMed1986

Estimation of visual function after optic neuritis: a comparison of clinical tests.

A group of 53 patients who had suffered an attack of unilateral (n = 45) or bilateral (n = 8) optic neuritis more than six months before were subjected to a battery of tests to determine their spatial contrast sensitivity, visual field, and colour vision. The 106 eyes investigated were classified according to their clinical status and visual acuity at the time of the study into unaffected (n = 45), recovered (n = 33), and non-recovered (n = 28). At least one of the three tests gave an abnormal result in 67%, 88%, 100% of the three groups respectively. The results obtained with these three tests showed a significant statistical association.

Adolescent↗
PubMed1986

The pattern-elicited electroretinogram. I. A tool in the early detection of glaucoma?

The pattern-elicited electroretinogram (PERG) was recorded in 75 patients known with glaucoma, each one of them having a normal visual acuity, and compared with the results in normal test subjects. Although there is a great overlap between normal and glaucomatous eyes, a lower average amplitude and a delay in latency is recorded in the case of glaucoma. A correlation was sought between the PERG outcome on the one hand and different glaucomatous parameters (visual field loss, intraocular pressure, cup disc/ratio) on the other; this could only be confirmed for the cup/disc ratio. In beginning glaucoma the PERG is more often disturbed than the VECP.

Adult↗
PubMed1985

Blue-yellow colour vision changes as early symptoms of ethambutol oculotoxicity.

To find out the most sensitive parameter of early toxic ocular changes, a group of patients was extensively examined at regular intervals during therapy with ethambutol. Colour vision abnormalities could be detected using the desaturated panel of Lanthony in the presence of normal visual acuity, normal visual fields, normal visual-evoked potentials and a normal panel D-15 test. Major blue-yellow errors were found in treated patients without visual complaints as well as in a group of healthy volunteers, but there was a significant difference between both groups. In a later stage of intoxication, blue defects, red-green defects or tritanomalous defects can be observed, together with other symptoms of ocular intoxication.

Adult↗
PubMed1979

Interference of 50 Hz electrical cortical potentials evoked by TV systems.

Application of TV systems for generating patterned stimuli for the examination of the electrical cortical potentials has disadvantages caused by the frame frequency of 50 Hz of TV sets. Apart from a larger variability in latency times of the electrical potentials as compared to the results obtained by projector systems, a 50-Hz noise on the recordings mediated through the visual system may be seen. These disadvantages can be ameliorated by increasing the frame frequency of the TV set.

Evoked Potentials↗
PubMed1977

Differential diagnostic aspects between optic neurititis and chiasm tumors.

Two patients with a pituitary tumor were first considered to have an optic neuritis from the clinical picture. The electrophysiological examination with VECPs gave results which did not offer a definite differentiation between both diseases, whereas perimetry and X-ray examination were decisive.

Adenoma, Chromophobe↗
PubMed1976

Clinical importance of the electro-oculogram with special reference to the chloroquine retinopathy.

Examination of the EOG is surely worthwhile in cases of generalized pigment alteration and in juvenile foveal dystrophies. Its value in the control of chloroquine treatment is still doubted, but the method will become better if an EOG is made before treatment is started. EOGs made during the treatment can then be compared with those made earlier. As a result, the large interindividual variation is replaced by the much smaller intraindividual variation. In a group of normals and patients, the intraindividual standard deviation appeared to be about 10% of the original value of the EOG. Using this criterion, we think the EOG to be a valuable tool in preventing chloroquine retinopathy, although it is not yet certain if static perimetry with red light is still a better method.

Arthritis, Rheumatoid↗