The Item Response Theory (IRT) is constituted as a probabilistic basis to measure latent constructs by understanding that the items are the basic units of measurement within a questionnaire. A recent study that evaluated the change in the quality of life of 218 myopic patients undergoing Excimer laser corneal surgery held in San Jose, Costa Rica, showed how patients that underwent this type of surgery improved their quality of life significantly. The NEI-VFQ-25 instrument was applied for data collection. It consists in 25 items that measure the Vison-Related Quality of Life (VR-QOL) grouped in 12 subscales. The instrument should be used at least twice in each patient and is commonly used 4 or 5 times over time to evaluate the real change in VR-QOL. This implies a long runtime, for this reason we propose to study the informative capability of each item to identify if it is possible to simplify the instrument without loss of information. The IRT was analyzed using the MULTILOG program, which includes estimates of the parameters using the maximum likelihood method and model of graded responses, allowing to demonstrate the ability of information and discriminant power each item. The study has revealed that it is feasible to achieve a simpler instrument able to provide the same level of information.