Search PubMed⌕ Search

Biomedical subjects

H G Trier

Publications and source records attributed to H G Trier.

36 records · Page 2Linked to original sources

[Use of ultrasound in ophthalmology].

In ophthalmology, ultrasound is applied in diagnostics as well as in surgery and therapy. This paper gives a short survey on both applications. Ultrasonic phacoemulsification is of considerable practical importance for modern cataract micro-surgery with intraocular lens implantation. Applications of that kind require consideration of ultrasonic bioeffects and equipment safety. Diagnostic use of ultrasound includes biometry (echometry), tissue examination and characterization, and vascular investigations in eye and orbit. The application of diagnostic ultrasound on in-patients, its individual indications, and the appropriate methods (A, B, automatic biometric devices for axial length measuring, M, Doppler) are described. Examples of commercially available instruments for the different applications are given. In comparison with other disciplines ophthalmic A-mode and B-mode echography is characterized by: refined depth resolution and lateral resolution; the important part of quantitative methods for clinical evaluation of echograms; and the advanced level of quality assurance for equipment performance. Refined tissue evaluation requires optimized and reproducible equipment parameters. To ensure these conditions the clinical echographer must be educated and willing to test performance and quality of his equipment. Finally, a perspective of actual research in diagnostic ultrasound of the eye is given.

Equipment Design↗

[An ocular toxicity study with flupirtine as an example of evaluation of possible ocular drug side effects in human volunteers (author's transl)].

Animal experiments do not provide complete information on all the possible ocular side effects and the toxicity of a new drug. Several functional or dynamic parameters of vision can only be tested in humans as they are either do not exist in laboratory animals or their assessment requires a subjective contribution by the test person. A study was carried out on a new analgesic substance (Flupirtine) in which a large number of such parameters were tested in young healthy volunteers. The results were subjected to statistical analysis with a two-factor partlyhierarchical anova and no toxic effects were detected. The study shows how such parameters of visual function can be tested in humans.

Adult↗

[Quality assurance for diagnostic ultrasonic equipment in A- and B-mode in ophthalmology (author's transl)].

Quality assurance for diagnostic ultrasound in ophthalmology is of growing importance and will be the subject of new standards and regulations. Methods for equipment performance testing by means of electric test signals in A- and B-mode equipment are described, both for comparative evaluation of equipment and for routine quality assurance tests. Newly developed test signal generator for checking the time scale in ultrasonic biometry of the eye are presented.

Eye Diseases↗

[New technique of ultrasonic biometry (author's transl)].

A new measuring system for echo return times is described, which renders it possible to measure simultaneously the three axial lengths of the living eye (length of cornea plus anterior chamber, length of the lens and of the vitreous) with ultrasound in real time and to process the data numerically. The repetition rate for the measurements is optimized up to the limit: each transmitted wave is registered. The computer either generates a measuring protocol with statistical data (mean value, standard deviation) or the variation of the three echo return times is displayed graphically. In clinical practice the unit is used routinely for rapid determination of optimal implant lenses, etc.

Anterior Chamber↗

[First experiences with an instrument for TV display of digitally encoded text information for the visually handicapped (author's transl)].

An instrument was developed which allows the display, in enlarged form--especially for visually handicapped persons--of text information as used in modern data-acquisition systems such as writing automats, screen editing devices, and television text display (in England, Ceefax). With the aid of electronic character generators, the text is displayed continually, moving from right to left in one line on the screen of a commercial TV set. Rate of movement, size, brightness, and color of the characters (and/or the background) can be selected arbitrarily. We performed a preliminary reading test with visually handicapped subjects from a rehabilitation center for blind persons. The resulting optimal parameters for text display and the achieved reading speed with the system are discussed.

Adult↗

[Ultrasound diagnosis in simulated middle-ear-effusions in isolated human temporal bones (author's transl)].

By means of simulated middle-ear effusions in isolated human temporal bones it could be demonstrated, that ultrasonic echos of the drum show typical patterns if the middle-ear is filled with fluid or not. In normal air-filled drums there is only the echo of the tympanic membrane, whereas in fluid-filled drums a second echo from the bony medial wall of the tympanon appears. --A method is described how to perform ultrasonograms under visual observation of the tympanic membrane.

Ear Diseases↗

[Normal glasses].

Explore the source record for details and available documents.

Eyeglasses↗