Corneal and conjunctival changes caused by commonly used glaucoma medications

Area of Science:

• Ophthalmology
• Ocular Surface Disease
• Drug Formulation

Background:

• Topical glaucoma medications are essential for managing intraocular pressure.
• Preservatives, particularly benzalkonium chloride (BAK), are common in these formulations.
• Concerns exist regarding the potential ocular surface toxicity of preservatives used in glaucoma medications.

Purpose of the Study:

• To investigate and compare the epithelial corneal and conjunctival changes induced by different topical glaucoma medications with varying preservatives.
• To assess the impact of different preservative systems on ocular surface health in a rabbit model.

Main Methods:

• New Zealand white rabbits received daily or twice-daily treatments for 30 days with artificial tears, brimonidine Purite, bimatoprost, dorzolamide, timolol maleate, or latanoprost.
• Corneal damage was quantified using scanning electron microscopy and a standardized grading scale.
• Conjunctival inflammation was assessed via light microscopy, counting inflammatory cells in different tissue layers.

Main Results:

• Artificial tears and brimonidine Purite showed significantly less corneal damage compared to dorzolamide, timolol, and latanoprost.
• Bimatoprost also demonstrated significantly lower corneal damage scores than dorzolamide, timolol, and latanoprost.
• Eyes treated with artificial tears or brimonidine Purite exhibited reduced conjunctival inflammation compared to those treated with timolol or latanoprost.

Conclusions:

• Glaucoma medications with higher concentrations of benzalkonium chloride (BAK) led to increased corneal damage and conjunctival inflammation.
• Preservatives like Purite or reduced BAK levels may be associated with better ocular surface tolerance.
• Optimizing preservative formulations in glaucoma medications is crucial for maintaining ocular health during long-term treatment.