Evaluation of advanced visual field defects by computer assisted kinetic perimetry

Background: Conventional kinetic perimetry is of especial use in case of ad vanced scotoma. However, examiner dependency is a major drawback. Purpose o f this study was to evaluate the clinical feasibility and intraindividual s catter of computer-assisted kinetic perimetry in monitoring advanced visual field defects of various origins. Methods: Examinations were carried out with the Tuebingen Computer Campimet er (background lumincance 10cd/m(2)). In an initial session, the localizati on of the scotoma border is estimated with conventional manual kinetic peri metry. In the subsequent computer assisted kinetic mode, an individually ad justed set of vectors is designed. Each vector crosses the manually assesse d 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 identica l characteristics as in manual kinetic perimetry. Stimulus presentations ar e repeated six times in a randomized order. Patients' responses are recorde d and additionally corrected for mean individual reaction time. A "local ki netic threshold" (mean) and a related parameter for dispersion (standard de viation) are assessed. Results: Four subjects with advanced visual field loss of various origin (r etinitis pigmentosa, vigabatrin-associated visual field defect, glaucomatou s nerve fibre layer defect, and postgeniculate visual pathway defect) parti cipated in this study. Maximal difference between manual-kinetic and automa ted kinetic thresholds reaches from 1.7 degrees to 5 degrees. Local scatter (standard deviation) of kinetic threshold, assessed by computer-assisted p erimetry, varies between 0.1 degrees and 3.0 degrees. Conclusion: Computer assisted kinetic perimetry is a new, useful, examiner- independent, reliable method for effective evaluation and monitoring of adv anced visual field loss.