<b>Introduction:</b> Currently all inhaled antimuscarinic drugs used in COPD and asthma treatment have a warning because the possibility of worsening narrow-angle glaucoma. The GOLD guidelines (2016) report this adverse effect only by use in solution through facemask. This study was performed to determine whether the risk of acute angle-closure glaucoma (AACG) occurs with all antimuscarinics or it is device related. <b>Methods:</b> A systematic review of the literature was conducted searching for case reports, cohort, case-control and RCTs in PubMed, Cochrane and Embase and FDA/EMA and pharmaceutical companies websites. Two of the authors independently selected studies that met the inclusion criteria (AACG in patients using inhaled antimuscarinics). <b>Results:</b> 17 reported cases of AACG were caused mainly by repeated use of nebulized ipratropium in patients with exacerbation of COPD or asthma, usually after 24 hours of treatment. Most of cases (75%) occurred with nebulization of salbutamol/ipratropium. Use of eye protection glasses and well-fitting mouthpiece/mask was not related to AACG. In the largest studies with chronic use with tiotropium (UPLIFT/TIOSPIR), no cases of AACG were reported. <b>Conclusions:</b> Cases of AACG were not reported in chronic treatment of COPD or asthma. The published cases involve acute use with repeated doses of nebulized ipratropium/salbutamol. Based on the evidence, warnings on antimuscarinics should be limited to these conditions.