ENThe application of a Clinical decision support system on creation of visual materials for an online medical learning is discussed in this work. An additional function of a Clinical decision support system on creating decision trees is presented to enhance student understanding of complicated medical research data. As an example the eye disease data set (2146x33) was used to help identify risk factors that are related to a rare pseudoexfoliation syndrome. The method on creating clinical decision support trees is presented. Six decision trees are used in online learning course materials on diagnostics of eye diseases and treatment.