The parameter stability of a high dk rigid lens material

Area of Science:

• Ophthalmology and Optometry
• Biomaterials Science
• Contact Lens Technology

Background:

• Increasing use of rigid, high oxygen permeability (Dk) contact lenses aims to reduce hypoxia.
• Concerns exist regarding material stability, including scratching, wettability, deposition, and parameter changes.
• Previous studies on silicone acrylate polymers show mixed results regarding parameter stability.

Purpose of the Study:

• To evaluate parameter stability of a high Dk rigid fluorocarbon contact lens material.
• To assess changes during both daily wear and monthly extended wear schedules.
• To investigate lens integrity, including surface scratching and parameter variations over time.

Main Methods:

• Thirty-five subjects were divided into two groups: daily wear (Group I) and monthly extended wear (Group II).
• Lens parameters and integrity were monitored every three months over the study period.
• Statistical analysis (ANCOVA) was used to determine significant changes in lens parameters and surface scratching.

Main Results:

• A statistically significant increase in surface scratching was observed in both daily and extended wear groups.
• Center thickness showed a statistically significant reduction (0.022 mm) in the daily wear group (Group I) after 12 months.
• No significant changes were found in other measured parameters for either group or between groups.

Conclusions:

• Rigid fluorocarbon contact lenses demonstrate stable parameters under both daily and extended wear conditions.
• Observed reduction in center thickness for daily wear lenses is not clinically significant.
• High Dk fluorocarbon materials offer a stable option for rigid contact lens applications.