This prospective randomized study aimed to compare the effects of nebulizer drugs on unilateral or bilateral dilation of the pupil that may develop due to mask incompatibility or patient incompatibility in patients receiving inhaled therapy. Following the approval of the local ethics committee, this study was carried out prospectively and observationally in the period from October 1, 2018 to April 1, 2019 in an emergency clinic with an annual capacity of 600,000 patients in a tertiary education and research hospital. The patients were divided into three groups: those given salbutamol alone (200 mcg), those given ipratropium alone (250 mcg/2ml), and those receiving both salbutamol and ipratropium. The pupil diameters of the patients included in the study were measured twice using a pupilometer device at hours 0 and 2 of treatment. Ninety- one patients that received inhaler treatment in the emergency department were included in the study. The process of treatments given to patients with indications was not interrupted. Ipratropium and salbutamol (49.5%) were used together in 45 patients, ipratropium alone in 38 (41.7%), and salbutamol alone in eight (8.8%). When the absolute delta ratios were compared, a statistically significant difference was observed between the patients given salbutamol and those given ipratropium, and between the patients that received salbutamol and those given salbutamol and ipratropium (p=0.001, 95% CI: 1.36-6.11 and p<0.001, 95% CI: 1.51- 6.19, respectively). Salbutamol caused statistically significantly greater pupil diameter changes than the other drugs. Although neurological diagnoses are considered in patients with anisocoria, it should be kept in mind that anisocoria may also be due to the current or the treatment being given.