Impact of Glaucoma Medication on Ocular Tissue
Impact of Glaucoma Medication on Ocular Tissue
Open-angle glaucoma and ocular hypertension require chronic topical treatment whose active ingredients can have some local side effects. Furthermore, different preservatives are present in the bottles to avoid contamination by common pathogens. Among all the preservatives, benzalkonium chloride is the most common and its toxic effects on the ocular tissue are well known. The purpose of this article is to investigate the ocular effects of glaucoma medication on ocular tissue, and in particular the ocular changes caused by preserved antiglaucoma drugs. Moreover, the shift from preservative-containing to preservative-free drugs, or the use of alternative preservatives with a lighter toxicity could be useful to decrease the negative impact of glaucoma medications on ocular tissues and to improve the patient's compliance. The outcome of filtering surgery could change on the basis of a previous topical therapy.
Chronic glaucoma is the second ocular disease leading to blindness. In 2000, the number of people with primary glaucoma was estimated at nearly 66.8 million, with 6.7 million individuals suffering from bilateral blindness. Glaucoma is characterized by a progressive optic neuropathy. Topical medical treatment is mainly used as first-choice therapy to avoid the onset of further irreversible optic nerve damage and visual field defects. Most of the patients are medically treated for a long time, because surgery is reserved in case of intolerance, inadequate response to topical therapy or damage progression.
Six different classes of intraocular pressure-lowering molecules are currently available, including α-adrenergic agonists, β-blockers, carbonic anhydrase inhibitors (CAIs; topical and systemic), parasympathomimetics, prostaglandin analogues and sympathomimetics. The efficacy changes among these classes, ranging from approximately 30% for the prostaglandins/prostamides to approximately 18% for the topical CAI. When choosing the medical treatment for glaucoma, it is important to understand not only the aims of therapy, but also their mode of action, and the local and systemic side effects of each medication. Many antiglaucoma drugs are available, and the choice of therapy must take into account quality of life, cost and compliance. These drugs include, besides the active agent, the vehicle and preservative, which can be responsible for local and systemic side effects. However, while the active agents are fundamental for treatment of the disease, preservatives are not thought to be dangerous and sometimes it is difficult to avoid them.
Abstract and Introduction
Abstract
Open-angle glaucoma and ocular hypertension require chronic topical treatment whose active ingredients can have some local side effects. Furthermore, different preservatives are present in the bottles to avoid contamination by common pathogens. Among all the preservatives, benzalkonium chloride is the most common and its toxic effects on the ocular tissue are well known. The purpose of this article is to investigate the ocular effects of glaucoma medication on ocular tissue, and in particular the ocular changes caused by preserved antiglaucoma drugs. Moreover, the shift from preservative-containing to preservative-free drugs, or the use of alternative preservatives with a lighter toxicity could be useful to decrease the negative impact of glaucoma medications on ocular tissues and to improve the patient's compliance. The outcome of filtering surgery could change on the basis of a previous topical therapy.
Introduction
Chronic glaucoma is the second ocular disease leading to blindness. In 2000, the number of people with primary glaucoma was estimated at nearly 66.8 million, with 6.7 million individuals suffering from bilateral blindness. Glaucoma is characterized by a progressive optic neuropathy. Topical medical treatment is mainly used as first-choice therapy to avoid the onset of further irreversible optic nerve damage and visual field defects. Most of the patients are medically treated for a long time, because surgery is reserved in case of intolerance, inadequate response to topical therapy or damage progression.
Six different classes of intraocular pressure-lowering molecules are currently available, including α-adrenergic agonists, β-blockers, carbonic anhydrase inhibitors (CAIs; topical and systemic), parasympathomimetics, prostaglandin analogues and sympathomimetics. The efficacy changes among these classes, ranging from approximately 30% for the prostaglandins/prostamides to approximately 18% for the topical CAI. When choosing the medical treatment for glaucoma, it is important to understand not only the aims of therapy, but also their mode of action, and the local and systemic side effects of each medication. Many antiglaucoma drugs are available, and the choice of therapy must take into account quality of life, cost and compliance. These drugs include, besides the active agent, the vehicle and preservative, which can be responsible for local and systemic side effects. However, while the active agents are fundamental for treatment of the disease, preservatives are not thought to be dangerous and sometimes it is difficult to avoid them.
