The Ocular Surface in Glaucoma

Purpose: To review the effects of preservatives on the ocular surface and assess how preserved eyedrops can affect clinical outcome in patients with glaucoma. Rationale: Dry eye and other symptoms of ocular surface disease are frequently encountered in patients with glaucoma and ocular hypertension and associated with the use of preserved topical antiglaucoma medications. The most commonly used preservative in ophthalmic solutions is benzalkonium chloride, which has adverse effects on the production and quality of tears and can cause damage to the corneal surface and conjunctival epithelia. Findings: Evidence from in vitro human cell culture and animal and clinical studies suggests that benzalkonium chloride is toxic to ocular tissues, even at very low concentrations. Use of benzalkonium chloride can result in clinical symptoms that disrupt treatment and reduce patients' quality of life. Conclusions: Switching patients to preservative-free antiglaucoma treatments greatly improves tolerability, reducing the incidence of adverse events such as burning, stinging, and dry eye. Preservative-free antiglaucoma formulations therefore offer clinical benefits to patients in terms of improved safety and increased likelihood of adherence to treatment.