The use of benzalkonium chloride in topical glaucoma treatment

ENGLISH SUMMARY: Glaucoma is a leading cause of the global prevalence of irreversible blindness. The pathogenesis of glaucoma is not entirely known, but the major risk factors include advancing age, genetic predisposition, and increased intraocular pressure (IOP). The only evidence‐based treatment is a lowering of IOP through the use of eye drops, laser procedures, or surgical interventions. Although laser treatment is gaining recognition as a first‐choice treatment option, the most common approach for managing glaucoma is IOP‐lowering eye drops. A major challenge in the treatment is the occurrence of adverse events and poor adherence. In this context, the ocular surface is an area of great concern, as most glaucoma patients have dry eye disease (DED), which is largely caused by eye drops. Preservation with benzalkonium chloride (BAK) is a controversial topic due to its potential role as a significant cause of DED. A systematic review and meta‐analyses investigate potential differences in efficacy and safety between BAK‐preserved and BAK‐free anti‐glaucomatous eye drops (I). Many of the included studies report on ocular surface damage caused by the application of BAK‐preserved eye drops. However, the meta‐analyses addressing hyperemia, number of ocular adverse events, and tear break‐up time did not identify any significant differences. The latter is likely due to varying measurement methods, different endpoints, and study durations. It is, therefore, possible that the large variations between the studies conceal differences in the safety profiles. The efficacy meta‐analysis finds that there are no differences in the IOP‐lowering effect between BAK‐preserved and BAK‐free eye drops, indicating that BAK is not necessary for the effectiveness of eye drops. To promote more homogeneous choices of endpoints and methods when evaluating BAK‐preserved and BAK‐free glaucoma treatments, a Delphi consensus statement was performed. In this study, glaucoma experts and ocular surface disease experts reached consensus on the key factors to consider when designing such studies (II). The hope is to have more studies with comparable endpoints that can systematically show the potentially adverse effects of BAK. The preclinical studies in the current Ph.D. research focus on conjunctival goblet cells (GCs). GCs are important for the ocular surface because they release the mucin MUC5AC, which is an essential component of the inner layer of the tear film. BAK preservation may dama