The primary aim of the OPTIPULM study is the evaluation of recorded pulmonary function curves and, based on them, the computer modelling of lung deposition for the individually used or potentially applicable inhalation drugs. The secondary aims include assessing the patients' inhalation device usage and providing recommendations for its optimization based on the recorded breathing curves and deposition calculations. The study also compares results across different flow rates and device resistances, aiming to identify the device with the highest modelled lung deposition for each patient. Understanding and Improving Inhalation Therapy in Lung Disease The OPTIPULM study looks at how well inhaled medications reach the lungs of people living with asthma or COPD (chronic obstructive pulmonary disease). It aims to improve treatment by helping doctors choose the best inhaler for each patient based on how they breathe. Every patient breathes differently, and not all inhalers work the same way. Sometimes the medicine doesn't reach deep enough into the lungs, which can make treatment less effective. This study helps doctors better understand which device works best for each individual. What happens during the study? No new treatments or changes to medication are made. Patients do a regular breathing test (like blowing into a tube). A computer program uses this breathing data to simulate how much medicine reaches the lungs with different inhalers. Doctors can then make more personalized choices for inhalation therapy. Who can take part? Adults with asthma or COPD who are able to use their inhaler correctly and complete a breathing test. What is the benefit? Although the study does not change treatments directly, it helps improve future care by identifying the best-matching inhaler for each patient. This can lead to better symptom control and fewer exacerbations.