Veränderung des NPC bei Personen mit Konvergenzinsuffizienz nach I.F.S.-Visualtraining

Abstract

Purpose. The aim of this study was to evaluate the efficacy of the I.F.S. visual therapy (convergence training) developed by Bruce Evans in a randomized-controlled setting. The analysis of the changes of the near point of convergence (NPC) was the main target of the study. Material and Methods. 20 subjects (39.0 ± 15.32 years) with convergence insufficiency and an NPC > 10 cm underwent 4 weeks of visual therapy in a randomised-controlled singleblind setting. The verum group followed the I.F.S. exercises, while the control group performed a placebo therapy. Before and after the training phase, the NPC and the positive fusional vergence (PFV) were measured in all subjects and the Sheard and Mallett criteria were also assessed. The CISS questionnaire was used to record and quantify subjective symptoms. Results. The statistical analysis (α = 0.05) shows that the NPC of the verum group improved significantly compared to the control group (p = 0.0008) and within the verum group only (p = 0.0002). The positive effect of the I.F.S. exercises is confirmed by the also significant improvement of the PFV. Conclusion. The results as well as the practical experience with the exercises indicate that the I.F.S. visual therapy proves to be effective for individuals with a convergence insufficiency and an NPC > 10 cm in improving the near point of convergence. Keywords. convergence insufficiency, near point of convergence, NPC, visual therapy, convergence training, I.F.S. exercises