[A.R.G.U.S. A model for an interactive visual field and visual pathway atlas]. / A.R.G.U.S. Modell für einen interaktiven Gesichtsfeld- und Sehbahnatlas.

A.R.G.U.S. is a data base that connects visual field defects directly with possible lesion sites that are presented graphically. By means of a touch screen or "mouse," scotomata can be depicted on a VDU, while on a second monitor the computer program simultaneously shows the resulting defects in the visual pathway. It is possible to page through different sections of the visual pathway; the lesion is probably located in the section where the affected fibers lie the closest to each other and where the non-affected fibers are the farthest apart. Additionally, the VDU depicting the visual pathway can show the surrounding anatomic structures in the form of brain sections. Even in these sections, lesions can be superimposed interactively; the resulting scotomata are simultaneously depicted on the "visual field VDU." Anatomic and functional details can be displayed by touching the structure of interest. If necessary, a video clip can be activated in the same way. New anatomic findings can be considered by modifying the course of the fibers of the visual pathway. This new technique is especially helpful in distributing comprehensive neuro-ophthalmological knowledge.

[A new white-noise campimeter]. / Ein neues Rauschfeldkampimeter.

In this prototype white-noise field is now generated on a high definition adjustable 19" colour monitor. With the help of a "touch-screen" the patient can draw the borders of his scotoma himself. As the white-noise stimulus is produced by software, there is a much greater variability of white-noise field specifications (brightness, intensity of noise, colour, ...). Furthermore, these parameters can be changed exclusively in circumscribed parts of the noise field (e.g. in a scotoma area). By that way a simulation or even a quantification of perceived noise field defects can be realized. Fixation is controlled with the help of an IR video camera. Input and storage of data as well as their presentation and output (on a Laserwriter) have been substantially improved.

[Fundus-oriented perimetry. Evaluation of a new visual field examination method for detecting angioscotoma]. / Fundus-orientierte Perimetrie. Evaluation eines neuen Gesichtsfeld-Untersuchungsverfahrens bezüglich der Detektion von Angioskotomen.

BACKGROUND: Conventional automated perimeters usually work with a given set of grids and thus are normally not adapted to individual conditions. This fact restricts efficiency of this method not only for any single examination but also for follow-up studies. MATERIALS AND METHODS: A new method (patent pending) is introduced which superimposes an individual perimetric grid--corrected in respect to orientation, position and size--onto a patient's fundus image. A recently developed software realizes this procedure in a comfortable manner: the digitized fundus image is loaded into the computer by e.g. photo-CD or disc, depicted on a control monitor and mirrored if necessary. Assuming a central fixation, the foveola is translationally shifted to the center of the perimetric grid by the help of a crosshair. The blind spot which has been previously determined with kinetic perimetry is then superimposed onto the optic disc of the fundus image using a rotation and zoom function. In this way, it is possible to adapt the perimetric grid directly to the underlying individual fundus findings: thus, stimuli can be spatially concentrated or more frequently tested in special regions of interest. Additionally, test points can be dragged away from delicate positions to avoid artifacts. Examinations were carried out on a high resolution colour VDU of the Tübingen Electronic Campimeter (TCC). Alternatively, suited bowl perimeters can be used. RESULTS: In order to test the precision of the superimposing procedure, fundus oriented perimetry was performed to detect angioscotomata in 13 ophthalmologically normal subjects. Using dark stimuli (12'), visual field defects in the expected region, caused by retinal vessels, could be detected in 7 cases (= 54%). The resulting attenuation of differential light sensitivity in this circumscribed region was up to 12 dB. CONCLUSIONS: By means of a morphologically adapted, individual arrangement of stimulus locations fundus-oriented perimetry enables detection of even minute (angio-) scotomata.

Automated perimetry with bright and dark stimuli.

Conventional perimeters use bright stimuli. In this study, dark stimuli were also used. Dark stimuli are employed for testing due to their lack of effects of local scatter and are utilized with the purpose of preferentially stimulating the off-system, but their presentation with optical methods is difficult. This problem is solved by the use of a computer monitor. The objective of this study was to compare directly measurements obtained with bright and dark stimuli. Therefore, the central 30 degrees of the visual field of ten subjects with no ophthalmologic pathology was examined with bright and dark stimuli (size 10- and 30-min-of-arc). Threshold estimation was performed with the 4/2 method. Concerning the 10-min-of-arc dark stimulus, no measurement outside the central 15 degrees could be performed because of insufficient dynamic range (sometimes even the darkest stimulus was not seen). Comparing the results obtained using bright and dark stimuli of the same size, we could not find a significant difference in sensitivity for this age group.