[Ocular toxicity of benzalkonium]

In order to meet the requirements of the pharmacopeia, ophthalmic preparations have to be manufactured in conditions that can secure their sterility before use and can prevent the development of micro-organisms after opening of the vial. The addition of an appropriate preservative is a way to meet this requirement. However, in addition to their lack of efficacy in certain conditions, they can be problematic in terms of formulation, stability and interaction with the packagings. Furthermore, their daily and repeated use in chronic pathologies such as glaucoma, dry eye or allergy has revealed their nuisance. Moreover, the recognition of certain parameters such as life quality and therapeutic observance has strengthened the proofs that have already been clinically shown. The review of the experimental and clinical data already published about the toxicity of the preservatives shows that almost every ocular structure is affected to various extents. From the first assumption data to preclinical and clinical proofs, this article highlights the evolution of the understanding process towards the toxic role of preservatives.