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Ulrich Schiefer

Publications and source records attributed to Ulrich Schiefer.

15 recordsLinked to original sources
PubMed2006

Scotoma mapping by semi-automated kinetic perimetry: the effects of stimulus properties and the speed of subjects' responses.

PURPOSE: The study aimed firstly to determine the effects of stimulus variables on the detection of a scotoma border and, secondly, to study the reproducibility of the method during semi-automated kinetic perimetry. METHODS: The size of the physiological blind spot in 18 young normal subjects was measured with a video-campimetric device, the Tübingen computer campimeter (TCC). Kinetic stimuli of two different sizes and at four different levels of luminance were presented. Examinations were repeated within 2 weeks. Measurements were corrected for individual response times and the area of the blind spot was computed. The effects of stimulus strength and size and the repeatability of blind spot measurements were evaluated by an analysis of variance. RESULTS: The physiological blind spot showed significant inter- and intraindividual variations in size (least square means ranging from 17 to 49 square degrees), with a standard deviation of 6.8 square degrees. The measured size of the blind spot increased as a function of decreasing stimulus value, by reducing either the relative brightness or the size of stimuli. Use of a correction for each subject's speed of responses nearly halved the level of random variance. The temporal sequence of measurements (the order in which they were performed) had no apparent effect on the calculated values of blind spot size. CONCLUSIONS: Semi-automated kinetic perimetry can determine the size of the physiological blind spot with good repeatability in young, normal subjects. Determination of each individual's speed of response and inclusion of this variable in the calculations reduced variance of the measure significantly. This study confirmed the presence of considerable interindividual differences in the size of the physiological blind spot.

Adult↗
PubMed2005

Quantification of stato-kinetic dissociation by semi-automated perimetry.

The difference in threshold sensitivities that are found when examining the visual field (VF) with static versus kinetic perimetric methods is called stato-kinetic dissociation (SKD). In this pilot study, we describe a semi-automated procedure for quantifying SKD. Fifteen patients with VF defects were examined with kinetic and static perimetry. SKD values were defined as positive when the static scotoma was larger than the kinetic one. We found significant local variations of SKD along scotoma borders with the individual reaction time as an important criterion when determining kinetic thresholds. There was a verifiable SKD in all patients with locally negative values in eight subjects.

Adult↗
PubMed2005

Pupil size and Perimetry--a pharmacological model using increment and decrement stimuli.

BACKGROUND: To assess the influence of natural and pharmacologically induced pupil size fluctuations on differential luminance sensitivity threshold (DLS) using bright (increment) and dark (decrement) stimuli. METHODS: Twelve healthy volunteers (20-30 years) were examined under the effect of phenylephrine 2%, dapiprazole 0.5%, and placebo. Pupil size was recorded by infra-red video camera in sessions without and with visual field examination (Tübingen Computer Campimeter). DLS was estimated at 9 locations within the central 20 degrees visual field, using bright and dark 26 min-of-arc-stimuli (10 cd/m(2) background, 4-2-1 dB thresholding strategy, four reversals). RESULTS: There were substantial inter-individual differences in pupil size and pupil size fluctuations. Intra-individual differences were small. Independently of medication, pupil size fluctuations were reduced by more than one-third when a subject was undergoing perimetric examination. Pupil size affected DLS on its own (slope 0.21 dB/mm; 95% CI: 0.09-0.33 dB/mm), differently at different stimulus locations, and to a greater extent with increment than with decrement stimuli (slope difference 0.13 dB/mm; 95% CI: 0.00-0.26 dB/mm). CONCLUSIONS: Campimetric examinations have a stabilising effect on pupil size fluctuations. Pupil size affects DLS with bright stimuli more than with dark stimuli; in normal young subjects this effect is not relevant for clinical or normative studies.

Adrenergic alpha-Agonists↗
PubMed2005

Comparison between semiautomated kinetic perimetry and conventional Goldmann manual kinetic perimetry in advanced visual field loss.

PURPOSE: To compare quantitatively visual field (VF) results obtained using a new standardized semiautomated kinetic perimetry (SKP) with those obtained by conventional Goldmann manual kinetic perimetry (MKP) in patients with advanced VF loss. DESIGN: Prospective, single-center, observational comparative case series. SUBJECTS AND METHODS: Seventy-seven eligible patients (36 suffering from advanced retinal nerve fiber layer loss, 20 with concentric constriction of the VF, and 21 with hemianopia) were included in the study. One eye of each patient was examined on the same day with MKP and SKP. Three isopters, identical in both tests, were chosen to assess the extent of the VF loss. To compare the location and size of the corresponding isopters obtained with MKP and SKP, intersection areas of superimposed isopters were expressed as a percentage of union areas. MAIN OUTCOME MEASURES: The area and position of isopters for a defined stimulus condition obtained with both methods were compared. Test duration and patients' preference were also evaluated. RESULTS: Isopters obtained with Goldmann MKP enclosed areas smaller by 20% (confidence interval [CI], 12%-27%). The mean intersection area of Goldmann and SKP VFs was 1763.1 square degrees (CI, 1558.6-1967.7) smaller than the union for stimulus III4e over all groups of patients. Semiautomated kinetic perimetry was preferred by 60% of patients with concentric constriction of the VF. Median duration of the examination was 15 minutes and did not differ significantly between the 2 methods. CONCLUSIONS: Our results indicate that SKP isopter shape and size were very comparable to those obtained on the same eyes with MKP. Semiautomated kinetic perimetry may represent a more standardized method of kinetic perimetry, which still takes advantage of perimetrist-patient interaction to diagnose and monitor advanced VF loss in clinical practice.

Adolescent↗
PubMed2005

Factors influencing reaction time during automated kinetic perimetry on the Tübingen computer campimeter.

PURPOSE: To determine the effect of age, examination, location, luminance, subject, and vigilance on reaction time (RT) in automated kinetic perimetry. METHODS: Thirty-six normal volunteers (20-70 years old) underwent kinetic campimetric examinations, during which RTs (time from appearance of a stimulus to response) were recorded. Stimuli with a diameter of 26 minutes of arc (Goldmann III) were presented on horizontal vectors with an angular velocity of 2 deg/s. Thirty-two positions in the 30 degrees radius visual field were tested six times, at luminance levels of 41.62 and 110 cd/m2 (background 10 cd/m2). An analysis of RT variance (ANCOVA) was performed. RESULTS: Median RT increased with age from 370 ms (20-30-year-old subjects) to 440 ms (60-70-year-old subjects). There was a strong dependency of RT from the individual subjects examined (means range, 313-411 ms), from the course of one examination period, from the examination and stimulus luminance, and from the location in the visual field. CONCLUSIONS: Reaction time during automated kinetic perimetry varies considerably. This study shows that the factors of age, the subject examined, his or her daily condition, the course within one examination period, and the stimulus location and luminance are of relevance. For a much more reliable prediction of individual RTs and thus a precise assessment of local kinetic thresholds, application of some additional kinetic stimuli (RT time vectors) within the intact visual field areas is necessary.

Adult↗
PubMed2004

Distribution of scotoma pattern related to chiasmal lesions with special reference to anterior junction syndrome.

PURPOSE: To evaluate pathogenetic mechanisms and frequency distribution of visual field defects (VFDs) in patients with chiasmal lesions. Secondly, to reconsider the existence of "Wilbrand's knee" as far as referable to the anterior junction syndrome. METHODS: Consecutive visual field records related to chiasmal lesions were retrieved from the Tuebingen Perimetric Database. In all cases, at least one eye was examined with the Tuebingen Automated Perimeter using a standardized grid of 191 static targets within the central 30 degrees visual field, and a threshold-related, slightly supraliminal strategy. VFDs were classified according to standard neuro-ophthalmological categories. RESULTS: Results from 153 consecutive patients (65 male, 88 female) were evaluable. The majority (65%) of chiasmal lesions was due to pituitary adenoma, followed by craniopharyngioma (12%), astrocytoma (9%), and meningioma (8%). Vascular lesions in this region occurred rarely (2%). Three per cent of all patients had no final diagnosis. The majority (22%) of scotomas was attributable to involvement of the temporal hemifield in both eyes, with true bitemporal hemianopia being a very rare event (1%). Anterior junction syndrome, characterized by advanced visual field loss affecting the visual field centre in one eye and (possibly subtle) defects respecting the vertical midline in the fellow eye, was the second most frequent classifiable VFD (13%). Homonymous hemianopic VFDs occurred in 11% of all cases. Nine per cent of all patients exhibited monocular VFDs which did not respect the vertical midline, whereas in 3% of the subjects the monocular VFDs did not cross the vertical meridian. Binasal defects and posterior junction syndrome also occurred seldom (< 1%). Nineteen per cent of all visual field records of patients with chiasmal lesions had results, which could not be classified unequivocally, and an identical portion was rated normal. CONCLUSION: In patients with chiasmal lesions, incomplete involvement of the temporal hemifields in both eyes was the most frequent event (22%), followed by anterior junction syndrome (13%). The latter entity at least clinically indicates the proximity of the pre-chiasmal ipsilateral optic nerve and decussating fibres emanating from the inferior nasal hemiretina of the fellow eye. However, this cannot provide conclusive evidence for the existence of anterior Wilbrand's knee.

Adolescent↗
PubMed2004

[Quantification of isopters using semiautomated kinetic perimetry (SKP) in glaucoma patients with advanced retinal nerve fiber layer (RNFL) loss].

PURPOSE: To quantify the area of isopters obtained using a new technique of kinetic visual field examination--semi-automated kinetic perimetry (SKP)--in case of advanced retinal nerve fiber layer (RNFL) loss, caused by glaucoma. MATERIAL AND METHODS: Forty-one subjects (19 men, 22 women; mean age 66.5 +/- 12.5 years) suffering from open-angle glaucoma (30 patients), normal tension glaucoma (5 patients), juvenile glaucoma (2 patients) and PEX glaucoma (4 patients) were examined, using SKP program implemented in Octopus 101 instrument (Haag-Streit, Koeniz, Switzerland). One eye of each patient was tested using three stimuli according to the Goldmann classification. The stimuli III4e and I4e were obligatory. Additionally one stimulus (I3e or I2e) was used depending on the character of the defect. The stimulus angular velocity was kept constant at the level of 3 degrees/s. Obtained visual field (VF) results were classified according to the Aulhorn classification into stage III (26 VF) and IV (15 VF). The areas of isopters were measured in deg2. RESULTS: The mean area of isopter III4e was 9860 deg2, I4e--5171 deg2, I3e--1093 deg2, I2e--1093 deg2 in the group of Aulhorn stage III. In the group of Aulhorn stage IV the mean area of isopter III4e was 7488 deg2, I4e--3736 deg2, I3e--1109 deg2 and I2e--818 deg2. The mean test time was 16 min. (range 9-25 min.), 15.7 min. in the group of Aulhorn stage III and 16.5 min. in the group of Aulhorn stage IV, respectively. CONCLUSION: SKP seems to be an effective method for quantitative assessment and evaluation of isopter and scotoma areas (in deg2). In this study it was demonstrated that in case of more advanced stages of glaucomatous visual field loss (Aulhorn stage IV), the areas of isopters appeared to be smaller.

Aged↗
PubMed2004

[Comparison of SKP (semi-automated kinetic perimetry) and SASP (suprathreshold automated static perimetry) techniques in patients with advanced glaucoma].

PURPOSE: To compare the results of conventional suprathresold automated static perimetry (SASP) and a new method of kinetic visual field examination (semi-automated kinetic perimetry--SKP) in patients with advanced retinal nerve fibre layer (RNFL) defects, caused by glaucoma. MATERIAL AND METHODS: Nineteen patients (10 women and 9 men) suffering from advanced open-angle glaucoma (17 patients) and low tension glaucoma (2 patients) were enrolled in this study. The mean age was 65.3 years (range 49.0-82.9 years). One eye of each subject was examined with SKP and SASP, both implemented in Octopus 101 perimeter (Haag-Streit, Koeniz, Switzerland) on the same day. The examiner using SKP did not know the SASP results. The static visual field examination was performed first. In order to compare visual fields results obtained with both methods, only central 30 degree area of the visual fields was taken into consideration. The area obtained by creating a virtual isopter (option of SKP software) located between the position of defective and intact visual field regions of SASP and the area of I4e isopter obtained with SKP (stimulus angular velocity 3 degrees/s) were measured in deg2 and compared. RESULTS: The mean area (+/-SD) of I4e isopter obtained with SKP was 1882 deg2 (+/- 510 deg2) and the mean area of SASP 30 degree visual field was 1737 deg2 (+/- 546 deg2). This difference was not statistically significant. CONCLUSION: Quantitative comparison of static and kinetic perimetry is a difficult task to perform. The SKP software offers a possibility of direct quantitative assessment of the area of each isopters in deg2. This study shows that the results of visual field examinations obtained with both methods in this group do not differ significantly between SASP and SKP.

Aged↗
PubMed2004

[Applicability of semi-automated kinetic perimetry (SKP) in the assessment of the visual field loss due to retinitis pigmentosa].

PURPOSE: To assess the applicability of a new technique of kinetic visual field examination--semi-automated kinetic perimetry (SKP)--in patients suffering from the visual field defects due to retinitis pigmentosa. METHODS: Thirty-five patients (19 women, 16 men: mean age 38.4 years) suffering from retinitis pigmentosa (10 with with Usher syndrome, one with Bardet-Biedl syndrome and one with Refsum syndrome) were examined using SKP software, implemented in Octopus 101 instrument (Haag-Streit, Koeniz, Switzerland). Three stimuli (1114e and 14e obligatory) were used to assess the hill of vision of each patient. The area of each isopter was measured in deg2. The test time was measured automatically in minutes. RESULTS: The visual field results were classified as complete or incomplete midperipheral "ring scotoma" (group I--13 patients) and concentric loss of the visual field (group II--22 patients). The area of 1114e isopter was 6147.5 deg2 in the group I and 1961.7 deg2 in the group II. The area of 14e isopter was 1468.4 deg2 and 781.7 deg2, respectively. The mean test time was 10 min. (range 4-20 min.): 8 min. in the group I and 13 min. in the group II. CONCLUSIONS: There is a large diversity of patterns of the visual field loss in retinitis pigmentosa. SKP, in contrary to widely used manual perimeter, gives a possibility of quantification of the visual field area. Future studies may be able to monitor the progression of the visual field loss caused by retinitis pigmentosa.

Adult↗
PubMed2004

[Recent developments in kinetic perimetry].

The manual kinetic perimetry using Goldmann instrument is still widely used and remains a "gold standard" in examining patients with any kind of advanced visual field loss and impaired co-operability. Nevertheless, Goldmann instrument has several disadvantages, such as examiner dependence, response variability, lack of standardization of parameters, poor repeatability. The latest development in kinetic perimetry, which was realized at the University Eye Hospital in Tuebingen (Germany) is semi-automated kinetic perimetry (SKP), using Octopus 101 instrument (Interzeag/Haag-Streit, Koeniz-Bern, Switzerland). It is an examiner-independent, standardized and reproducible method. Additionally, obtained results can be corrected for the mean individual reaction time. This paper will briefly present characteristic, advantages and application of SKP in clinical practice.

Eye Diseases↗
PubMed2003

Increased detection rate of glaucomatous visual field damage with locally condensed grids: a comparison between fundus-oriented perimetry and conventional visual field examination.

OBJECTIVE: To compare detection rates of glaucomatous visual field defects (VFDs) between the conventional 6 degrees x 6 degrees stimulus grid and locally condensed target arrangements in morphologically suspicious regions. METHODS: A total of 66 eyes of 66 patients with glaucoma or patients suspected of having glaucoma (34 females and 32 males; age range, 14-85 years) were enrolled in this study. Individual, local target condensation was realized by fundus-oriented perimetry (FOP) using a campimeter and compared with the results of conventional automated perimetry (CAP), obtained with the Humphrey Field Analyzer (30-2 grid). RESULTS: Twenty-three of the 66 patients showed normal findings with both methods; 27 had concordantly pathological results. In 15 patients we obtained normal findings with CAP, whereas FOP revealed early glaucomatous VFDs. Only one patient showed VFDs with CAP, whereas FOP results were normal. Scotoma detection rates significantly differed between the 2 methods (P<.001, sign test). Test duration with FOP was more than doubled compared with CAP. When considering only FOP points coinciding with the 6 degrees spacing of the 30-2 grid, there was no longer a significant difference between FOP and CAP (P>.25, sign test). This indicated that the target pattern, rather than the perimetric device, was most relevant for detecting glaucomatous VFDs. Follow-up throughout a series of 3 subsequent sessions at 6-month intervals revealed repeatable results in more than two thirds of all eyes for both FOP and CAP. CONCLUSIONS: Fundus-oriented perimetry that uses individually condensed test grids significantly increases the detection rate of glaucomatous VFDs in morphologically conspicuous areas compared with CAP using equidistant (6 degrees x 6 degrees) target arrangements. Repeatability is comparable between both methods.

Adolescent↗
PubMed2002

Stereotactic fractionated radiotherapy in patients with optic nerve sheath meningioma.

PURPOSE: To evaluate the effectiveness of stereotactic fractionated radiotherapy (SFRT) in the treatment of optic nerve sheath meningioma (ONSM). METHODS AND MARERIALS: Between 1994 and 2000, a total of 39 patients with either primary (n = 15) or secondary (n = 24) ONSM were treated with SFRT and received a median total tumor dose of 54 Gy using 1.8 Gy/fraction. RESULTS: The radiographic response to SFRT was documented in all patients as stable disease (no change) except for 1 patient with a partial response. After a median follow-up of 35.5 months, all patients with ONSM were alive without recurrence. The visual fields and visual acuity were improved in 6 of 15 and 1 of 16 examined eyes in patients with primary ONSM, respectively, and in 6 of 24 and 7 of 26 examined eyes in patients with secondary ONSM, respectively. Stable visual fields and visual acuity was observed in 8 of 14 and 15 of 16 patients with primary ONSM, respectively, and in 17 of 24 and 19 of 26 patients with secondary ONSM, respectively. Except for reversible alopecia and erythema, no other SFRT-related toxicity was observed. CONCLUSION: SFRT represents a very effective and low-toxic treatment modality for ONSM. Despite a median follow-up of 3 years, this series of primary ONSM holds promise for future studies. It adds substantial evidence that SFRT may definitely become a standard treatment approach in selected cases of ONSM.

Adolescent↗
PubMed2002

Visual field constriction and electrophysiological changes associated with vigabatrin.

PURPOSE: We investigated functional, morphological and electrophysiological changes in patients under anti-epileptic therapy with vigabatrin (VGB), a GABA aminotransferase inhibitor. METHODS: 20 epileptic patients treated with vigabatrin (age range 25-66 years) were enrolled in this study. The referrals were made by the treating neurologist, based on suspected or known visual field changes in these patients. Two patients had vigabatrin monotherapy, 18 patients were treated with vigabatrin in combination with other antiepileptic drugs. None of the patients reported visual complaints. Patients were examined with psychophysical tests including colour vision (Farnsworth D15), dark adaptation threshold, Goldmann visual fields and Tuebingen Automated Perimetry (90 degrees). A Ganzfeld ERG and an EOG following the ISCEV standard protocol were also obtained. Additionally, all patients were examined with the VERIS multifocal ERG including recordings of multifocal oscillatory potentials. RESULTS: Visual acuity, anterior and posterior segments, colour vision and dark adaptation thresholds were normal in all patients. Of 20 patients, 18 presented visual field constriction. All patients with visual field defects revealed altered oscillatory potentials waveforms in the ERG, especially in those patients with marked visual field defects. Multifocal oscillatory potentials were also delayed in those patients. In some patients a delayed cone single flash response (6/20), a reduced mERG amplitude (12/20) and a reduced Arden ratio (9/20) were found. CONCLUSIONS: The present data indicate an effect of vigabatrin on the inner retinal layers. Since abnormalities of the oscillatory potentials were seen in all patients with visual field defects a dysfunction of GABA-ergic retinal cell transmission might be assumed.

Adult↗
PubMed2002

[Tuebingen Education System (TES)--An interactive case demonstration software].

BACKGROUND: Presentations based on slides, videos and/or computer presentations are usually sequentially structured, resulting in an inflexible order of the demonstrated information and examination results. However, in (medical) education such a system only inadequately reflects the real physician-patient situation. MATERIALS AND METHODS: The software solution presented here is based on the widespread computer programme Microsoft PowerPoint(R) (PPT) which offers an opportunity to present information via text boxes, figures, illustrations, video sequences and/or audio files in an user-friendly way. However, PPT's capabilities of simulating realistic decision processes (e. g. by "interactive keys" and "hyperlinks") are still restricted as far as adapting the order of the information/slides to the individual demand is concerned. The Tuebingen Education System (TES) uses an additional user interface based on Visual Basic. By means of this, every examination result or information can be chosen via five additional pull-up menus in an arbitrary order. Furthermore, the pathway - i. e. the examinations used to arrive at a diagnosis - as well as the costs incurred are documented in parallel and are finally compared to the costs incurred using an optimum pathway. RESULTS: TES has been used routinely in the education of the students and residents of the University Eye Hospital Tuebingen for three (half-)terms. Meanwhile, an adapted version of TES is used to educate students in the department of paediatric surgery. TES was judged in extensive evaluations of both subjects very positively. CONCLUSIONS: TES is an easy to use tool suitable for lecturers and students, a further step towards realistic, practice-oriented and interactive education.

Computer-Assisted Instruction↗