Preservative-related problems in soft contact lens wearers

Area of Science:

• Ophthalmology
• Toxicology
• Materials Science

Background:

• Soft contact lens wear is common, but complications like red eyes and lens intolerance can occur.
• Previous studies have suggested a link between contact lens solutions and adverse ocular reactions.

Purpose of the Study:

• To investigate the cause of red eyes and lens intolerance in soft contact lens wearers.
• To determine the role of preservatives in contact lens solutions causing ocular inflammation.
• To assess the efficacy of preservative-free solutions and heat disinfection in managing these symptoms.

Main Methods:

• Retrospective analysis of 61 patients with soft contact lens-induced red eyes and intolerance.
• Clinical examination to rule out infectious agents.
• Treatment with preservative-free solutions and heat disinfection.
• Skin and conjunctival challenge testing with preservatives, including Thiomersal.

Main Results:

• Absence of infectious agents in all patients.
• Significant improvement in symptoms and lens tolerance after switching to preservative-free solutions.
• Slow resolution of corneal signs, but successful return to lens wear for most patients.
• Conjunctival challenge with Thiomersal elicited a rapid response in all tested subjects, despite negative skin test results in most.

Conclusions:

• Preservatives, particularly organic mercurials like Thiomersal, are a likely cause of soft contact lens-induced red eyes and intolerance.
• Preservative-free solutions combined with heat disinfection are effective in managing these reactions.
• Conjunctival challenge is a more sensitive method than skin testing for identifying preservative hypersensitivity in contact lens wearers.