[Unclear atrophy of the optic nerve].
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
U Schiefer
Publications and source records attributed to U Schiefer.
Effect of visual restitution training on absolute homonymous scotomas.
The authors examined 16 patients with stable homonymous visual field defects (HVFDs) with static automated perimetry (SAP). Training effect E was defined as difference of the proportions of absolutely defective locations in all test locations, before and after visual restitution training (VRT). E was 0.05 +/- 0.05 (mean +/- SD). The authors observed a relevant training effect (E >or= 0.12) in two subjects, but only monocularly. VRT has little effect on absolute HVFDs in SAP.
Adult↗
K-Train--a computer-based, interactive training program with an incorporated certification system for practicing kinetic perimetry: evaluation of acceptance and success rate.
PURPOSE: To evaluate, in an experimental study, an interactive, computer-based teaching procedure for kinetic perimetry that incorporates an evaluation system for scoring examination technique. METHODS AND SUBJECTS: K-Train was developed and based on the original user interface of the new semi-automated kinetic perimetry (SKP) feature of the OCTOPUS 101 perimeter (HAAG-STREIT, Koeniz, Switzerland). The trainer creates a 3D individual "hill of vision" for a specific pathology and the trainee can individually select target characteristics and independently define origin, end and direction of each kinetic stimulus with the help of vectors. Quality of the perimetric examination can be quantitatively assessed by the ratio of intersection area and union area of the trainee's result and the related trainer-defined original isopter. This ratio and other parameters are used to define a score of "perimetric quality". The general acceptance of K-Train was assessed in 30 participants in two perimetric courses. The success rate was examined by comparing the scores before and after a perimetric training session. RESULTS: The K-Train course was graded by the participants with an average score of 1.35 (range 1-3) in a scoring system ranging from 1=excellent to 6=unsatisfactory. The average perimetric quality score increased from 48 before to 59 (max. 100) after the training (27 trainees) indicating that K-Train was able to achieve and also verify a considerable success rate. CONCLUSION: The acceptance of K-Train, a computer-based, interactive tool that allows for certification, education and quality control of kinetic perimetry, is high. K-Train is capable of improving a trainee's individual performance in kinetic perimetry and of verifying this by an appropriate scoring system.
Adult↗
[Conventional perimetry. Part 3: Static perimetry: grid--strategy--visualisation].
Methods for visual field examination using static strategies began with manual static profile perimetry. The transition from a linear stimulus alignment along the profile section to a two-dimensional grid arrangement introduced the era of static grid perimetry. The use of computers makes it possible to automate and standardise this process, allowing the examiner to choose the visual field area, an adequate grid and the optimal strategy, while leaving the processing, visualisation and recording completely observer-independent. This contribution is based only on conventional static procedures for visual field examination (the use of white on white perimetry) as this technique is easily accessible, standardised and well established in everyday practice.
Diagnosis, Computer-Assisted↗
[Conventional techniques of visual field examination: part 4 Static perimetry: interpretation--perimetric indices--follow-up--perimetry in childhood].
Visual field examination with fixed stimuli was first realized in manual static profile perimetry. The transition from a linear stimulus alignment along a profile section towards a two-dimensional arrangement introduced the era of static grid perimetry. Application of computer technology nowadays allows automation and standardization of this procedure, which enables the examiner to select the necessary visual field area, the adequate grid, and the optimal strategy for an estimation of differential luminance sensitivity. Furthermore, the computer independently takes over the recording, visualization, and processing of the perimetric procedure. This contribution discusses conventional static visual field examinations since these are widely used, easily accessible, well established for practical application, and standardized. This paper (part 4) explicitly focuses on the correct interpretation of automated static strategies of visual field examinations. Furthermore the classification and scoring of visual field defects as well as quality control, progression analysis, and perimetry in childhood are addressed. This manuscript is based on three preceding parts, which were published in previous issues of this journal [27, 28, 29].
Child↗
[Integrated approach to the promotion of young academics in vision research at a European level].
The European Commission predicts a dramatic dearth of researchers and doctors in the near future. At the same time, highly qualified and motivated human resources form the only guarantee for further development of scientific knowledge for research and clinical application. This situation calls for an integrated approach to the promotion of young academics in vision research at a European level. The Marie Curie Program of the European Union is an ideal tool, which can be used particularly efficiently in vision research to promote international networking and dedicated advancement of young academics. The exemplary chances and opportunities of this strategy can be demonstrated by six specific measures of the University Eye Hospital in Tübingen. In particular, strictly defined medical areas will need to fully exploit their innovation potential in the future in order to secure their position in the global research area or even to expand it. New organizational concepts and long-term career options as well as a clear commitment to cutting-edge performance are the prerequisites for effective promotion of young academics.
Academic Medical Centers↗
[Conventional perimetry I: introduction--basics].
Evaluation of visual field findings is an essential ophthalmological task. Applying psychophysical principles enables non-invasive (topo-)diagnostics in case of unexplained visual loss or suspected lesions of the visual pathways. Furthermore, any kind of expert opinion or ability test depends critically on adequate visual field findings. Repeated examinations allow the functional follow-up of a disease and judgement of therapeutic efficiency. This paper is explicitly focused on conventional strategies of visual field examination, since these are widespread, easily accessible, standardized and well established in everyday practice. Part 1 of this continuing education series will mainly impart basic concepts in perimetry and psychophysics. It will also consider indications and the necessary general setup of a perimetric examination. Furthermore, a concept of scotoma classification is explained.
Humans↗
[Conventional techniques of visual field examination Part 2: confrontation visual field testing -- kinetic perimetry].
Evaluation of visual field findings is an essential ophthalmological task. Applying psychophysical principles enables noninvasive (topo-)diagnosis in cases of unexplained visual loss or suspected lesions of the visual pathway. Furthermore, any kind of expert opinion or ability test critically depends on adequate visual field findings. Repeated examinations allow functional follow-up of a disease and assessment of therapeutic efficiency. This paper explicitly focuses on conventional strategies since these are widespread, easily accessible, standardized, and well established in everyday practice over years. Standardized white-on-white perimetry with moving targets (kinetic perimetry) is the major topic of this paper (part 2) in addition to "rough"/preliminary confrontation visual field testing. This review series is aimed at imparting basic concepts in perimetry and psychophysics to ophthalmologists and also addresses interested physicians from other disciplines.
Eye Movements↗
Does visual restitution training change absolute homonymous visual field defects? A fundus controlled study.
AIM: To examine whether visual restitution training (VRT) is able to change absolute homonymous field defect, assessed with fundus controlled microperimetry, in patients with hemianopia. METHODS: 17 patients with stable homonymous visual field defects before and after a 6 month VRT period were investigated with a specialised microperimetric method using a scanning laser ophthalmoscope (SLO). Fixation was controlled by SLO fundus monitoring. The size of the field defect was quantified by calculating the ratio of the number of absolute defects and the number of test points; the training effect E was defined as the difference between these two ratios before and after training. A shift of the entire vertical visual field border by 1 degrees would result in an E value of 0.14. RESULTS: The mean training effect of all right eyes was E = 0.025 (SD 0.052) and all left eyes E = 0.008 (SD 0.034). In one eye, a slight non-homonymous improvement along the horizontal meridian occurred. CONCLUSIONS: In one patient, a slight improvement along the horizontal meridian was found in one eye. In none of the patients was an explicit homonymous change of the absolute field defect border observed after training.
Adult↗
[Proposed scoring system for assessment of functional impairment due to visual field defects].
INTRODUCTION: The purpose of the study is the development of a scoring system for the assessment of functional impairment due to visual field defects, based on the Esterman grid, but adapted to the existing system in the Federal Republic of Germany. METHODS: The score areas and the evaluation rules were altered iteratively, until the functional score by the new system matched as much as possible the score obtained from the existing system of geometrical defect patterns. RESULTS: The visual field is divided into 100 score areas, which are smaller in the visual field center and in its lower region, respectively. The areas inside the reference isopter are counted and taken as total function in percent. Areas with monocular perception are rated with 3/4 points. Functional impairment is defined as the difference of total function to 100%. For 9 of 20 defect patterns, the functional scores are equal. Another six patterns differ by 1-4%. The remaining 5 of 20 patterns differ by 6-8% in either direction. CONCLUSION: The new system is easier to apply, more consistent, and covers irregular defect patterns. The level of functional impairment is nearly identical with both systems. A transition to the scoring system would considerably increase the certitude and the quality of assessment especially in difficult cases.
Disability Evaluation↗
[Visual acuity testing in pre-school children: a comparison between the Sheridan-Gardiner test and the Räder (broken wheel) test].
PURPOSE: To evaluate the comparability between the well-established Sheridan-Gardiner test (SGT) and a new type of visual acuity test, called the Räder test (RT = broken wheel test) in pre-school children, and to compare test durations of these infant visual acuity tests. SUBJECTS AND METHODS: The RT consists of 16 cards with visus values of 0.16, 0.2, 0.25, 0.3, 0.5, 0.6, 0.8 and 1.0. One pair of cards depicting a car is used for testing. On one of the cards the car has intact wheels, on the other the wheels are incomplete, symbolized by a Landolt ring. The child must indicate, at a viewing distance of 3 meters, which of the wheels is incomplete. The SGT consists of seven visus plates: 5/60, 5/36, 5/24, 5/18, 5/12, 5/9 and 5/6. Each level is tested with one letter and can be repeated by the presentation of a further letter (A, H, O, T, U, V, X). The examination distance is 5 meters. The child must indicate, with reference to a card depicting all seven symbols, which letter the examiner is showing. The SGT and RT were performed in a randomized cross-over sequence in 30 children (20male, 10 female) of pre-school age (from 2 years up to and including the age of 5 years, mean 3.4 years +/- 0.77 SD, median 3.0 years). In all cases, the right eye was examined first. Examination duration was assessed for each acuity test, and for each eye separately with a stopwatch. The instruction time was not considered. The possible visual acuity values of both bests were replaced by a unified scale of visual acuity levels (ranging from 1 to 10). A difference of at least two levels was considered as relevant. The results were compared by means of the sign test at a significance level of 0.05. RESULTS: In particular, for higher visual acuity levels there were considerable differences, with SGT generally showing better results than RT: in 11 of 29 children, in both eyes RT values turned out to be at least 2 lines better than those obtained with SGT. The contrary situation, i. e., favoring SGT by more than 2 lines compared to RT, never occurred. According to the sign test, these differences were significant (p < 0.001). SGT revealed also clearly better visual acuity levels in those 22 children out of the 30, who exhibited differences by 2 lines or more in at least one eye (p < 0.001). The examination procedure with RT revealed problems in making the required directional decisions, especially between 2 and 4 years of age. This might interfere with the test interpretation and lead to distortion of the RT results. Total examination duration did not differ considerably between SGT (1.6 to 5.8 minutes, median 3.0 minutes) and RT (1.6 to 9.4 minutes, median 4.6 minutes), respectively. CONCLUSIONS: The Sheridan-Gardiner test generally shows better results than the new Räder (RT = broken wheel) test in pre-school children. Problems in making the required directional decisions may interfere with RT in this age group.
Bias↗
Progress in the genetics of glaucoma.
The term glaucoma describes a heterogeneous group of optic neuropathies that lead to optic nerve atrophy and permanent loss of vision. It is the second most prevalent cause of bilateral blindness in the Western world and affects over 60 million people worldwide. The hereditary forms of glaucoma are genetically heterogeneous. Different forms of glaucoma can be distinguished: the primary open-angle glaucoma of adult onset is the most common, representing approximately half of all cases. The juvenile-onset open-angle glaucoma is an uncommon autosomal dominant form of glaucoma with manifestation predominantly before the fourth decade of life. The primary congenital glaucoma is a clinical and genetic entity clearly distinct from the juvenile form, following an autosomal recessive mode of inheritance. At least eight loci have been linked to glaucoma (GLC1A-F, GLC3A/B) and three genes have been identified to date: MYOC, CYP1B1 and OPTN. In the last decade, there has been much progress in finding new genes, detecting disease-related mutations and determining allele frequencies within populations of different ethnical backgrounds, but little is known about the function of the mutated gene products and the underlying pathogenic mechanisms. This chapter attempts to summarize the current knowledge regarding glaucoma-associated genes.
Eye Proteins↗
Stereotactic fractionated irradiation of optic nerve sheath meningioma: a new treatment alternative.
BACKGROUND: Primary optic nerve sheath meningioma (ONSM) is a rare but almost invariably blinding tumour when its natural history is observed in a "wait and see" strategy. Surgery has hitherto only been advocated in case of progressive disease involving intracranial structures, as it leads to iatrogenic blindness in the overwhelming majority of cases. Therefore, treatment options bearing lesser risk of functional deterioration are highly desirable, both in cases of intracranial involvement as well as during earlier phases of the disease which are currently generally left untreated. The authors report the outcome of the largest series of patients to date treated by stereotactic fractionated irradiation as a new treatment approach in ONSM at all stages. METHODS: 15 patients (16 nerves) underwent stereotactic fractionated conformal irradiation with a total dose of 54 Gy, using standard fractionation. Main outcome parameters included visual acuity and visual field, as well as three dimensional remission as documented by imaging. RESULTS: Tumour control was confirmed in all 15 patients undergoing stereotactic fractionated conformal irradiation (mean follow up 37 (range 12-71) months). No patient developed functional deterioration during or after treatment. Moreover, visual acuity improved by more than two lines in one patient and the visual field improved in six cases. Visual outcome in the other patients remained unchanged. There were no significant side effects of radiation therapy. CONCLUSION: These data provide convincing evidence that stereotactic fractionated conformal irradiation is an effective treatment option for primary ONSM with minimal treatment related morbidity. It should therefore be considered as therapeutic option both in early stage ONSM where surgery cannot be justified as well as in later stages, where surgery is so far considered the first line approach.
Adolescent↗
An explicit no response instead of time-out in automated visual-field testing.
BACKGROUND: To evaluate the effect of response-acquisition technique on psychometric performance in visual-field testing, the conventional one-button yes/time-out method was compared with a two-button yes/no method for responding whether or not the stimulus was detected. There are a number of situations in which the single-button technique leads to ambiguous results. In this study, we thus expected the yes/no method to reduce tendencies towards habituation and automatic responding. Our hypothesis was that the two-button technique could reduce the rate of erroneous responses. METHODS: Luminance-difference sensitivity for bright stimuli (32') on a photopic background was evaluated at 26 locations within the central visual field (30 degrees) using a specially equalised video display unit and a modified 4/2-dB staircase strategy (six reversals, maximum-likelihood threshold estimation). Sixty-one ophthalmologically normal subjects (aged 20-30 years) were examined twice with each method. RESULTS: Mean sensitivities with the two-button yes/no method were found to be, on average, 0.13 dB above those measured with the one-button yes/time-out technique--a difference without clinical relevance. Within-subject variability did not differ between the two methods. However, the less intuitive two-button yes/no method had a slightly higher number of false responses in catch trials. CONCLUSION: Compared to the conventional one-button yes/time-out method, the two-button yes/no method in normal young subjects thus showed little difference in mean sensitivities and equivalent within-subject variabilities. Concerning our initial hypothesis, the yes/no method is of somewhat higher complexity and is not able to reduce the rate of erroneous responses. The one-button yes/time-out method fared a little better in error rate. In summary, the yes/no method is an alternative and additional possibility of response acquisition in visual-field testing, which is worthy of being tested in a clinical study with elderly subjects.
Adult↗
The relevance of stereopsis for motorists: a pilot study.
PURPOSE: To study the influence of stereoscopic depth perception on automobile driving performance. METHODS: Ten patients with strabismus and defective stereopsis were compared with ten healthy controls with respect to their performance in a series of automobile driving manoeuvres. The two groups were individually matched as to age, annual miles driven, years of licence holding and type of vehicle owned. After an ophthalmologic examination the subjects in each group performed the following series of driving tests: (1) stopping in front of an obstacle, (2) reversing into a parking space, (3) driving through a slalom course, (4) estimating the relative positions of two cars. All tests were performed binocularly and monocularly (with the non-dominant eye covered). RESULTS: Only in the slalom test did the normal subjects perform significantly better than the stereo-deficient subjects (odds ratio 10.5; P<0.01). In estimating position, normal subjects actually performed significantly worse (odds ratio 0.091; P<0.01). A significant distance ratio of 2.5 (95% CI 1.1-5.5; P=0.033) of the monocular with respect to the binocular performance of the normal subjects was found for the stopping task only, while the subjects with defective stereopsis showed no difference between their monocular and binocular performance. CONCLUSION: In this study, stereopsis had a positive effect on driving performance only in dynamic situations at intermediate distances.
Adult↗
Reaction time in automated kinetic perimetry: effects of stimulus luminance, eccentricity, and movement direction.
PURPOSE: To determine the effects of stimulus eccentricity and luminance level on the reaction time (RT) of young normal volunteers during automated kinetic campimetry. METHODS: We used a specially designed video-campimetric device equipped with a continuous infrared (IR) pupillographic fixation control (Tübingen Computer Campimeter) and recorded reaction times upon presenting horizontally moving small circular stimuli (size 26'; constant angular velocity 2 degrees /s) starting at 16 locations within the central 30 degrees -radius of the visual field. Two different levels of stimulus luminance were used (41.6 cd/m(2) and 110 cd/m(2)), while background luminance was 10 cd/m(2). Each stimulus was presented a total of six times in a randomized order. Subjects were 12 healthy young individuals (aged 21-30 years) with normal ophthalmic examinations. An analysis of variance (ANOVA) was performed on the data. RESULTS: RTs showed considerable inter- and intra-individual variation with individual least squares means (LSM, fitted values of a linear model) ranging from 305 to 454 ms, and residual standard deviation (R.S.D.) 66 ms. Reaction times did not differ significantly as a function of stimulus direction (P>0.6). Higher luminance levels produced significantly reduced reaction times for all stimulus locations and directions (mean reduction: 16 ms; P<0.0001). Reaction times increased with increasing eccentricity, in the mean by 1.8 ms per degree of visual angle, from 365+/-4 ms (S.E.M.) foveally, to 407+/-2 ms at 30 degrees eccentricity; (P<0.0001). CONCLUSIONS: Automated kinetic perimetry should be designed to cope with significant, variable interindividual response characteristics. Other stimulus related factors, such as eccentricity or luminance level, have a significant but comparatively small effect on reaction time within the central 30 degrees -radius visual field in healthy young individuals.
Adult↗
Hyperexcitatory activity in visual cortex in homonymous hemianopia after stroke.
OBJECTIVES: Damage to and destruction of neural afferents result in a disruption of sensory input, which causes reduced activity in the corresponding cortical areas. Conversely, there is also evidence that lesions in the sensory pathway induce changes in the intracortical connectivity resulting in augmented cortical activity due to disinhibition. As disinhibition is assumed to be involved in the reconfiguration of neural networks, its appearance after brain lesions might be relevant for the restitution of impaired brain functions. METHODS: The effects of lesions in the visual pathway on the activity in visual cortex were studied using magnetoencephalography. In order to compare the neural activity affected by the lesion with the activity associated with intact visual processing, only patients with unilateral, post-chiasmatic lesions resulting in homonymous hemianopia were examined. RESULTS: Stimulation within the scotoma resulted in reduced magnetic activity compared to the stimulation of the intact hemifield. Increased activity was observed when the border region of the scotoma was stimulated. CONCLUSIONS: It is concluded that the magnetic hyperactivity reflects cortical disinhibition induced by lesions in the visual system. Furthermore, the possible role of cortical disinhibition as a basis for cortical reorganization and as a precondition for the recovery of impaired visual functions is discussed.
Hemianopsia↗
[Evaluation of extensive visual field defects with computer-assisted kinetic perimetry].
BACKGROUND: Conventional kinetic perimetry is of especial use in case of advanced scotoma. However, examiner dependency is a major drawback. Purpose of this study was to evaluate the clinical feasibility and intraindividual scatter of computer-assisted kinetic perimetry in monitoring advanced visual field defects of various origins. METHODS: Examinations were carried out with the Tuebingen Computer Campimeter (background lumincance 10 cd/m2). In an initial session, the localization of the scotoma border is estimated with conventional manual kinetic perimetry. In the subsequent computer assisted kinetic mode, an individually adjusted set of vectors is designed. Each vector crosses the manually assessed visual field defect border almost perpendicularly, starting approximately 3 degrees within the scotoma. Each individual set of vectors can be stored and recalled for follow-up. Stimuli move along these vectors with identical characteristics as in manual kinetic perimetry. Stimulus presentations are repeated six times in a randomized order. Patients' responses are recorded and additionally corrected for mean individual reaction time. A "local kinetic threshold" (mean) and a related parameter for dispersion (standard deviation) are assessed. RESULTS: Four subjects with advanced visual field loss of various origin (retinitis pigmentosa, vigabatrin-associated visual field defect, glaucomatous nerve fibre layer defect, and postgeniculate visual pathway defect) participated in this study. Maximal difference between manual-kinetic and automated kinetic thresholds reaches from 1.7 degrees to 5 degrees. Local scatter (standard deviation) of kinetic threshold, assessed by computer-assisted perimetry, varies between 0.1 degree and 3.0 degrees. CONCLUSION: Computer assisted kinetic perimetry is a new, useful, examiner-independent, reliable method for effective evaluation and monitoring of advanced visual field loss.
Adult↗