K-Train–a computer-based, interactive training ... - Springer Link

Graefe’s Arch Clin Exp Ophthalmol (2006) 244: 1300–1309

CLINICAL I NVESTIGATION

DOI 10.1007/s00417-006-0291-9

U. Schiefer K. Nowomiejska E. Krapp J. Pätzold C. A. Johnson

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

Received: 11 August 2005 Revised: 20 January 2006 Accepted: 20 January 2006 Published online: 21 March 2006 # Springer-Verlag 2006

C. A. Johnson Welch-Allyn, Skaneateles, NY, USA

U. Schiefer (*) . K. Nowomiejska . E. Krapp . J. Pätzold University Eye Hospital, Department of Pathophysiology of Vision and Neuro-Ophthalmology, Tuebingen, Germany e-mail: [email protected] K. Nowomiejska Tadeusz Krwawicz Chair of Ophthalmology and First Eye Hospital, Medical University, Lublin, Poland C. A. Johnson Discoveries in Sight Research Laboratories, Devers Eye Institute, Portland, OR, USA U. Schiefer . J. Pätzold HAAG-STREIT Inc., Koeniz, Switzerland

C. A. Johnson Carl Zeiss Meditec, Dublin, CA, USA

Abstract 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 (HAAGSTREIT, 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

Introduction Kinetic perimetry is the method of choice for cases of profound visual field loss, such as retinitis pigmentosa and a variety of neuro-ophthalmological disorders. Assessing

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. Keywords Kinetic perimetry . Training . Education . Certification . Quality control

visual field borders or delineating the extent of advanced scotomas is primarily an edge-detection task. Moving targets may be more efficient for this situation than conventional automated static perimetry, which is usually based on a pre-defined grid of test locations. Furthermore,

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the kinetic technique seems to be more adequate in representing daily living situations than its static counterpart. This may be one reason why kinetic perimetry is required by several (European) authorities in regard to medico-legal issues (e.g. expert opinion and ability testing) [22]. Conventional manual kinetic perimetry is highly subjective and depends on the skills of the individual examiner. In the Optic Neuritis Treatment Trial, it was reported that manual kinetic perimetry was considerably more variable than standard automated static perimetry, in spite of technician training, certification procedures, and continual performance feedback [9]. Additionally it is difficult to maintain and demonstrate adequate examination conditions (e.g. constant target velocity, roughly perpendicular approach to the assumed

scotoma border). Finally, due to the success of automated static perimetry, skilled technicians who are experienced in kinetic perimetry are becoming an “endangered species”. Recently, semi-automated kinetic perimetry [SKP, formerly also called computer-assisted kinetic perimetry (CAKP)] was developed in order to standardise visual field examination with moving targets [16–18, 23, 24]. Each target with predefined characteristics (size, luminance, angular velocity) moves along a vector that defines the origin, direction and termination of the kinetic stimulus presentation. The purpose of this project was (1) to develop a modified version of the SKP software, by which individual 3D hills of vision representing various “artificial patients” with specific visual field loss can be implemented, the entire

Fig. 1 Main examination window of the training software. The left upper quadrant shows a “virtual eye” with variable pupil size and “natural” lid and gaze movements, which can be de- and re-centered interactively. Pupil size and position can be continuously recorded on a separate sub-window. The left lower quadrant of the window allows for control of the examination parameters, such as type, angular velocity, size and luminance of the stimulus. The vector type is routinely set to “test vector”. The “RT vector” option specifies presentation of moving targets in proven intact areas of the virtual visual field; in this manner, individual reaction time (RT) of the virtual patient can be assessed and used for automated compensation/correction of isopter displacement, a systematic source of variability in kinetic perimetry. RT vectors are denoted with doubleheaded arrows. The large window on the right side is used for control, visualisation and recording of the examination procedure:

the individual vector locations are represented by arrows; responses of the virtual patient are shown by small symbols on top of each vector (missing responses are shown by a filled arrowhead). This window shows the individual examination result of an advanced artificial Bjerrum scotoma. The small, vertically oriented tool bar in between offers features for editing the examination window, especially interactively creating, correcting or erasing the examination vectors, locally changing magnification of the examination window or drawing the isopters. It also allows for further evaluation and description of the examination results. The tool bar also permits the superimposition of age-related normative isopters for any chosen stimulus condition. It also can activate or deactivate the reaction time correction mode, thus interactively demonstrating the impact of individual reaction time of the virtual patient on the isopter location. Examination time is automatically recorded

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individual examination procedure of each trainee can be recorded, and a comprehensive score for certifying the individual skills of the candidate for the given task is automatically generated; (2) to assess acceptance of this training procedure, (3) to evaluate whether this software is able to improve a trainee’s individual performance in kinetic perimetry, and (4) to determine whether this improvement can be verified by a scoring system.

Fig. 2a, b Instructor’s windows. a Instructor’s window for “modelling” the individual 3D hill of vision of the virtual patient (advanced Bjerrum scotoma, see also Fig. 1) using triangulation tools. The user positions points with a certain “height” at a particular location on the hill of vision. In between the points, the height of the hill of vision is linearly interpolated by triangulation of all entered points. b Instructor’s window for entering characteristics specific to the virtual patient, such as age, individual frequency of seeing curves, repeatability, individual reaction time characteristics, pupil size, fixation characteristics

Methods Training device The K-Train software is based on the user-guided interface of the kinetic perimetry option developed for the OCTOPUS 101 instrument (HAAG-STREIT, Koeniz, Switzerland); the main examination window of the training software is identical to the clinical version [11] (Fig. 1). At present, this software is available in German and English. Each step of the trainee’s examination procedure, including each response of the virtual patient, is recorded. The two windows for entering instructor’s options, which are not accessible during the training mode, are the

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most important features of this software (Fig. 2a,b). One window is used for entering, i.e. “modelling”, the individual 3D hill of vision of the virtual patient using triangulation tools. The resulting hill can be visualised as a colour-coded representation of a local altitude (i.e. threshold sensitivity) distribution. Alternatively the resulting course of isopters can be demonstrated for a set of representative stimulus conditions. With the help of the second window (Fig. 2b), the instructor can define or modify individual characteristics of the virtual patient. The distribution of individual reactiontime characteristics is modelled for a non-Gaussian distribution and can be varied interactively. By altering the individual frequency of the seeing curve, the trainer can also determine the repeatability of the responses of the virtual patient: false-positive and false-negative response rate as well as the slope can be entered individually. Furthermore, the colours of the contour levels of the hill of vision are variable. Demographics and other portions of a patient record window are also completed by the instructor or by an auxiliary medical staff member (Fig. 3). Having finished the examination procedure for the right and left eyes and drawn the related isopters, the trainee is asked to categorise the visual field defect(s) using the builtin interactive classification system (Fig. 4). This is done for each eye separately; further details regarding binocular findings (e.g. homonymous hemianopia) can be added. The entire perimetric lesson could also be presented in a standardised, stand-alone MS PowerPoint session or even via a web-based course. However, these options cannot replace the interactive nature of the actual training procedure. Fig. 3 Patient record window, providing the trainee with comprehensive data regarding history and most relevant findings of the virtual patient

Training procedure In an introduction, the trainees are informed of basic principles and standards of (semi-)automated kinetic perimetry (see e.g. [10]) and familiarised with the userguided interface. The participants are informed that they should always move a target from non-seeing parts of the visual field (i.e. from the periphery towards the centre or from inside a visual field defect outwards) towards intact (seeing) areas. Individual stimulus presentation is usually carried out along vectors, which define the origin, direction and termination of target movement. Target movement (vectors) should be relatively constant and directed perpendicularly to the presumed scotoma border. According to Johnson et al., a velocity of 4°/s is an optimum compromise between spatial resolution and examination time [8]. A velocity range of 3–5°/s is thus recommended for routine SKP examination. At least 8–12 meridians should be examined in order to define one isopter. The stimulus condition III4e (26′, 320 cd/m2) should be routinely chosen for all patients in order to ensure at least one reference isopter is recorded under all circumstances. Results obtained with this stimulus condition are definitive for medico-legal purposes in Germany [22], and this also seems also be the case in some Anglo-American countries [2, 7, 12, 27]. At least two more stimulus conditions should be presented that are equally distributed over the individual hill of vision (i.e. an almost equidistant spacing of the isopters throughout the entire visual field should be achieved). At least one isopter should be located within the eccentricity of the blind spot (i.e. within a radius of 14°). For all isopters that fall completely within an eccentricity of 30°, an adequate near correction, using

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Fig. 4 Interactive scotoma classification, using the built-in option of the original kinetic perimetry software

thin rim trial lenses, should be provided if necessary. The correction should also include a cylindrical lens exceeding 1 D. Outside the central 30° visual field no correction (except adequate contact lenses) should be employed. For evaluation of the blind spot, the target condition I4e, 2°/s is recommended, with an adequate near correction if necessary. The recommended presentation of static targets (static perimetry “spot checks”) within the related “kinetic” isopter is realised by simply setting the angular velocity to 0°/s. Reaction-time vectors, which are placed within intact visual field areas, should be used in order to assess individual latencies of the (virtual) patient in order to compensate for a systematic inward shift of visual field margins and a systematic outward shift of scotoma borders. For special purposes, a manual stimulus presentation can be chosen. Simulating conventional manual kinetic perimetry as it is performed on a Goldmann instrument, the stimulus moves exactly the same way as the computer mouse or the electronic pen on the touch screen. Also in this mode, stimulus movement can be optionally documented—the width of the trace increases with decreasing angular velocity of the manually guided target. In a second session, the trainees are informed about quality control issues, especially related to kinetic perimetry, for example, isopters obtained with differing stimulus conditions should not cross. Isopters should not show local

discontinuities. Isopters obtained with small and dim targets should be located inside those assessed with larger and brighter stimuli. The blind spot has to be detected as an absolute scotoma in its typical location. Further suggestions for establishing plausibility of visual field loss include the presence of a relative afferent pupillary defect in the case of clearly asymmetric or unilateral visual field defects, a visual acuity impairment and the presence of reading disorders in cases of central scotomata, or a report on night blindness in cases of concentric constriction, which should also be established with manual confrontation perimetry, showing a widening of the isopters proportionally related to the increase of the examination distance. Scoring and certification procedure Several criteria are considered in related sub-scores. The default setting for the “specific weights” of each criterion can be altered according to the individual instructor’s options. They are listed in sections and add up to a final “perimetric quality score” with a maximum of 100% per each examined (monocular) visual field. The criteria are (1) examination quality (40%), (2) use of a standardised stimulus setting (in Germany: III4e), which is recom-

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Fig. 5 Results of participants. Top left Representative printout (left=front page) of a certificate form including scores, showing the trainee’s individual examination result (solid lines) and the original set of isopters of the virtual patient, suffering from glaucomatous visual field loss (dashed lines). Top right Backside of the certificate showing the original set of isopters and the patient’s record. Middle Results of two other (worse) trainees with the same virtual patient, demonstrating the considerable variation in kinetic perimetric results at an early training stage. Bottom Three examples of subscores: for each training record, the related proposed score, which is automatically determined by the algorithm, is given

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mended for expert opinion (10%), (3) adequate examination of the blind spot (10%), (4) use of reaction time vectors (5%), (5) adequate examination duration (5%), and (6) correct classification of the observed visual field defect(s) (30%). The training software merely offers suggestions for each sub-score, which can be accepted or modified by the instructor (Fig. 5, bottom). The sub-score regarding examination quality, i.e. item (1) of the above-mentioned listing, considers two aspects: (a) spatial concordance between the obtained perimetric result and the originally entered (virtual) hill of vision, and (b) adequate distribution of the isopters in relation to the given hill of vision. It does not seem to be appropriate to list the two aspects of this subscore separately, since they are strongly interrelated. Spatial concordance is defined as the ratio of the intersection area and the union area of the trainee generated and the computer-stored isopters. This sub-score reaches a maximum in case of perfect coincidence, and goes down to zero if the two isopter sets do not have anything in common (Fig. 6). Adequate distribution of isopters in relation to the hill of vision is judged by comparing the isopter areas (essentially a mean radius is compared because the ratio values are then obvious) obtained with various (at least three) stimulus conditions. A ratio of 1:2/3:1/3 is scored as an optimum; in cases of steeply-bordered (cliff-like) visual field defects, interactive correction of this sub-score may be necessary. Assessment of K-Train acceptance and success rate General acceptance of K-Train was assessed using standardised evaluation forms, which were distributed at the Annual National Ophthalmological Educational meeting “Augenärztliche Akademie Deutschland” (AAD 2005) (18 participants), which is comparable to the AAO meeting, and the 2005 Tuebingen “FUN+-Course”, addressing ophthalmologists with a special interest in functional diagnostics and neuro-ophthalmology (12 participants). The evaluation was carried out retrospectively with the anonymous data set. In this sample of 30 participants who were unfamiliar with the technique (17 females, 13 males, age range: 26–62 years; 15 residents, 11 general ophthalmologists, 3 ophthalmologists working in an eye hospital, 1 senior physician), the abovementioned scores were assessed before and after a perimetric training session. The majority of this sample

Fig. 6 The concordance between the trainee’s individual examination result and the real perimetric finding is quantified by the ratio of the intersection area and the union area for each isopter (schematic view)

(n=14) declared that they personally carry out perimetric examinations at least once monthly and judge on average 4.8 perimetric records per day (median 3, range 1–15). In a short initial session (30 min) the group was familiarised with the user-guided interface only. The task of the participants during the pre-training examination was to correctly examine an advanced “artificial” Bjerrum scotoma presented by K-Train (Figs. 1 and 2). This first perimetric examination was followed by a comprehensive perimetric training session of another 30 min. In the posttraining perimetric examination session, another virtual case was presented with a slightly modified history on the patient record window. This virtual patient had a Bjerrum scotoma identical to the initial case, with the only exception that the virtual field defect was mirrored along the horizontal meridian. This was done in order to maintain comparable experimental conditions in the pre- and posttraining examination session. An increase in the “perimetric quality score” by more than 10%, related to baseline, was rated as a relevant success.

Results The overall acceptance of the K-Train course was graded by the participants with an average score of 1.35 (range 1–3), based upon the German school grading system, ranging from 1=excellent to 6=unsatisfactory. All 30 participants rated the K-Train software as relevant for their personal ophthalmological activities. Twenty-six of these stated that the imparted knowledge would have a strong impact on their activities. Twenty-eight would recommend this course. Nineteen would like to participate in this course during the residency phase, seven during the practical year; another 15 requested implementation of K-Train as an element of continuous medical education. Figure 5 (top) shows a representative printout of a certificate with the related scores. The front page (top left) shows the trainee’s after-training examination result (solid lines) and the original set of isopters of the virtual patient suffering from glaucomatous visual field loss (dashed lines). The back of the certificate (top right) shows the original set of isopters and the patient’s record. It is important to mention that all applied vectors and stimulus conditions are precisely and completely documented. In this manner, suggestions for improvement can be proposed during a comprehensive “post-hoc discussion”. The centre of Fig. 5 depicts two results of different trainees for the same virtual patient, demonstrating the inherent variety of kinetic perimetric results obtained during an early training stage. The success rate of the training procedure is shown in Fig. 7. Twenty-seven of 30 participants could be analysed according for “improvement during the training”, because three of them were participating in this course for the

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second time. Twenty-three showed improvement, four showed worsening. The mean change in the results after the training was 11 points of improvement. The average of the perimetric quality score increased from 48 before to 59 after the training (27 trainees), indicating that K-Train is indeed able to achieve and also to verify a considerable success rate (Fig. 7). Figure 8 shows the sub-score “quality of examination”, which describes concordance of the virtual patient with the examination. The maximum possible score is 40. Examination duration of the advanced artificial Bjerrum scotoma (see Figs. 1 and 5 top) was 13±3 min (mean±SD).

Discussion In the early introductory period of his cupola perimeter, Goldmann established standards for maintaining a reliable examination procedure and for ensuring high-quality records [5]. However, the lack of inherent documentation of the examination process in this exclusively manual perimetric procedure does not allow any kind of sufficient post-hoc feedback. Training was only possible by direct supervision during the examination procedure of one perimetrist by a trainer. The training procedure can of course be facilitated by perimetric textbooks and atlases

Fig. 7 Total scoring results for 27 participants before and after the training procedure using K-Train. Each result is represented by a dot. Individual results are connected with a thin line. The mean (circle) and standard deviation (error bar) of each score are additionally shown

(e.g. [1]). Attempts have been made to further standardise kinetic perimetry and also to relate the individual kinetic results to (age-related) normative values [3, 4, 6, 8, 10, 13– 15, 17, 18, 24–28]. However, these issues are of only minor importance in regard to delineation of current unknown visual field defects. Simulating the examination procedure with the help of a computer to integrate artificial scotomas is an essential prerequisite for this purpose. To the knowledge of the authors, T.D. Williams was the first to develop a software module for training kinetic perimetry. However, because the examination procedure was entirely manually driven, scotomas could be delineated by simply moving the stimulus back and forth in an oscillating manner over the entire examination area. This procedure is somewhat comparable to tracing the surface of a coin on a piece of paper with the help of an oscillating pencil. Furthermore, the individual stimulus approach to the virtual visual field border is not recorded. Thus it is not possible to discuss the examination procedure afterwards. The authors are not sure whether Dr. Williams’ software comes up with specific topographic scotoma data for any arbitrary stimulus conditions [19–21, 25–27]. Prior versions of computer-based kinetic perimetry training procedures have also been described, but the technique was not

Fig. 8 “Quality-of-examination-subscore” results of 27 participants before and after the training procedure using K-Train. Each result is represented by a dot. Individual results are connected with a thin line. The mean (circle) and standard deviation (error bar) of each score is additionally shown

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as comprehensive or detailed as the one described in this manuscript. Vector-based kinetic perimetric strategies, as applied in semi-automated kinetic perimetry (SKP) and this training software, allow for exact recording of any stimulus condition, including origin, direction, termination and angular velocity of any target presentation [14, 17, 18, 23, 24]. The modelling of individual (pseudo) 3D hills of vision for each case allows one to obtain realistic visual field results for any selected stimulus condition. Additional features, such as variability of the response properties (frequency of seeing and reaction-time distribution) and an interactive integrated screen for fixation control of the “individual virtual patient” bring the training situation even closer to reality and can imitate various levels of difficulty. Semi-automated generation of a form for scoring and certifying the trainees’ records is an additional feature of K-Train. The recommended value of each sub-score can be altered by the supervisor according to his/her personal judgement. This procedure, on the one hand, may leave some room for subjectivity. On the other hand, an experienced supervisor can more adequately judge, for example, why an additional set of isopters is superfluous due to a steep decline of scotoma borders or that the assessment of the blind spot, which is situated within a profound visual field defect, is unnecessary. Since K-Train is exclusively based on software, a remote training program (via CD ROMs or even interactively via the Internet) is possible. However, additional individual certification in a remote situation using this training tool would be best with a personal identification and “surveillance” of the applicant. This study showed considerable acceptance for this training procedure. The success rate of the training procedure is shown in Fig. 7. It shows the improvement of the trainees during the training. Of the 27 participants who were analysed, 23 showed improvement, and 4 showed worsening. The mean change of the results after the training was 11 points of improvement. The success rate differed considerably for the subscores. The notable worsening of three individuals is basically due to the fact that they had forgotten to classify their results after the training, but had done so before. Therefore, inadvertent omission in this step resulted in a severe devaluation of the total quality score by 30%, which

of course might override all other training effects. Therefore, in general, a comparison of each sub-score is useful. Figure 8 shows the sub-score “quality of examination” which describes concordance of the virtual patient with the examination. The maximum score is 40. Other sub-scores showed little change from before training to after. This is mainly due to the fact that K-Train automatically selects the III4e stimulus by default, and routinely reminds the trainee with a “message box” to examine the blind spot, and to apply reaction time vectors before closing the examination procedure. It is clear that some improvement of the score is simply due to the repeat of the session. In order to test this, one would have to redo the procedure (using the mirrored scotoma) without any additional training and instruction procedure. However, it would be difficult to integrate this in a regular perimetric training course. It has not been proven yet whether these skills and thereby success are inherently transferred to other kinetic perimetric procedures and instruments (e.g. manual kinetic perimetry using the classic Goldmann perimeter). Furthermore, the amount to which the success is due to the K-Train training program itself rather than to the personal instructions cannot be derived from the perimetric quality score. Kinetic perimetry remains an important tool in cases of functional delineation and follow-up of profound visual field loss; this is especially true for neuro-ophthalmological patients. Futhermore, this technique is required by many (European) authorities for medico-legal purposes. The presented K-Train training software may be a helpful tool to standardise and evaluate education programs in this field. Understandable scores may further help to certify centres with adequately educated technicians applying kinetic perimetry technique, e.g. as “inclusion or quality criterion” for participation in multi-centre studies. Training, certification, quality-control assessment, immediate feedback and related factors have been shown to be vital components of multi-centre treatment trials employing perimetry as an outcome measure. In conclusion, this study demonstrates a high acceptance rate for K-Train, a computer-based interactive tool that allows for certification, education and quality control of kinetic perimetry. K-Train has proven capable of improving a trainee’s individual performance in kinetic perimetry using an appropriate verifiable scoring system.

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