Ophthalmologymiddle twist
A 76-year-old man with long-standing asthma has needed his reliever most nights for six weeks and now wakes twice a night wheezing. His preventer, budesonide with formoterol, is unchanged. He has hypertension and nasal polyps, and has taken perindopril and aspirin without change for eight years. Two months ago an eye clinic started three drops in both eyes for raised pressure: brimonidine, latanoprost and timolol. Examination shows scattered expiratory wheeze and no crackles. Which one of the following is most likely responsible for the deterioration in his asthma?