Research Objectives: To evaluate the refractive error in children aged 4 to 6 years before and after implementation of occlusion exercises monitoring visual acuity without and with correction and to evaluate amplitude and latency of visually evoked potential P100 wave before and after occlusion. Materials and Methods: This is a retrospective analysis of data collected from children with low vision who were seen and treated at the clinic for eye diseases of the University Hospital center Split in the period between 2012. to 2015. Study data is comprised of information collected from 30 patients aged 4 to 6 years old via clinical ophthalmic examination and data obtained through their parent/guardian interviews. We examined the visual acuity first by subjective methods of examination using optotypes and then by the sciascopy – the objective method of eye refraction examination. We recorded changes in VEP parameter values (amplitude and latency) depending on visual acuity, before correction, with correction and after implementation of occlusion exercises. Results: Within the analyzed group of 30 children, six children with astigmatic ansiometropia, eleven with hypermetropic ansiometropia and thirteen with myopic ansiometry were detected. Exercises by occlusion resulted in statistically significant improvement in visual acuity of the right (p=0.000) and left eye (0.001) compared to the pre-exercise condition. Also, value of right eye amplitude (p=0.000) and right eye latency (p=0.001) as well as the value of left eye amplitude (p=0.001) and left eye latency (p=0.003) were significantly improved after occlusion exercises compared to the pre-exercise status. Conclusion: Within the observed group of children, there is a statistically significant difference in refractory status before and after correction. Timely detection, determining the appropriate correction approach, completing the prescribed exercises, continuous monitoring and co-operation with parents are the most importand preconditions for successful treatment.