E. Krapp

Spatial pattern of glaucomatous visual field loss obtained with regionally condensed stimulus arrangements.

PURPOSE To assess the spatial distribution of glaucomatous visual field defects (VFDs) obtained with regionally condensed stimulus arrangements. METHODS Sixty-three eyes of 63 glaucoma subjects were examined with threshold-estimating automated static perimetry (full threshold 4-2-1 dB strategy with at least three reversals) on an automatic campimeter or a full-field perimeter. Stimuli were added by the examiner to regionally enhance spatial resolution in regions that were suspicious for a glaucomatous VFD. These regions were characterized by contiguous local VFDs, attributable to the retinal nerve fiber bundle course according to the impression of the examiner. The added stimulus locations were subsets of a predefined, dense perimetric grid. All VFD locations with P < 0.05 (total deviation plots) were assessed by superimposing the visual field records of all participants. RESULTS Glaucomatous VFD loss occurred more frequently in the upper than in the lower hemifield, with a typical retinal nerve fiber-related pattern and a preference of the nasal step region. More than 50% of the eyes with predominantly mild to moderate glaucomatous field loss showed defective locations in the immediate superior paracentral region within an eccentricity of 3°. CONCLUSIONS Conventional thresholding white-on-white perimetry with regionally enhanced spatial resolution reveals that glaucomatous visual field loss affects the immediate paracentral area, especially the upper hemifield, in many eyes with only mild to moderate glaucomatous visual field loss. Detailed knowledge about the spatial pattern and the local frequency distribution of glaucomatous VFDs is an essential prerequisite for creating regionally condensed stimulus arrangements for adequate detection and follow-up of functional glaucomatous damage.

Comparison of the new perimetric GATE strategy with conventional full-threshold and SITA standard strategies

PURPOSE A new, fast-threshold strategy, German Adaptive Thresholding Estimation (GATE/GATE-i), is compared to the full-threshold (FT) staircase and the Swedish Interactive Thresholding Algorithm (SITA) Standard strategies. GATE-i is performed in the initial examination and GATE refers to the results in subsequent examinations. METHODS Sixty subjects were recruited for participation in the study: 40 with manifest glaucoma, 10 with suspected glaucoma, and 10 with ocular hypertension. The subjects were evaluated by each threshold strategy on two separate sessions within 14 days in a randomized block design. RESULTS SITA standard, GATE-i, and GATE thresholds were 1.2, 0.6, and 0.0 dB higher than FT. The SITA standard tended to have lower thresholds than those of FT, GATE-i, and GATE for the more positive thresholds, and also in the five seed locations. For FT, GATE-i, GATE, and SITA Standard, the standard deviations of thresholds between sessions were, respectively, 3.9, 4.5, 4.2, and 3.1 dB, test-retest reliabilities (Spearmans rank correlations) were 0.84, 0.76, 0.79, and 0.71, test-retest agreements as measured by the 95% reference interval of differences were -7.69 to 7.69, -8.76 to 9.00, -8.40 to 8.56, and -7.01 to 7.44 dB, and examination durations were 9.0, 5.7, 4.7, and 5.6 minutes. The test duration for SITA Standard increased with increasing glaucomatous loss. CONCLUSIONS The GATE algorithm achieves thresholds that are similar to those of FT and SITA Standard, with comparable accuracy, test-retest reliability, but with a shorter test duration than FT.

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

PurposeTo 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.MethodsConsecutive 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° visual field, and a threshold-related, slightly supraliminal strategy. VFDs were classified according to standard neuro-ophthalmological categories.ResultsResults 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.ConclusionIn 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.

Age-dependent normative values for differential luminance sensitivity in automated static perimetry using the Octopus 101.

Purpose:  To determine age‐dependent normative differential threshold values for the Octopus 101 instrument and to create a smooth mathematical model characterizing the age‐dependency and asymmetry of the hill of vision.

K-Train–a computer-based, interactive training program with an incorporated certification system for practicing kinetic perimetry: evaluation of acceptance and success rate

PurposeTo 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 subjectsK-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.ResultsThe 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.ConclusionThe 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.