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N.L. Dassanayake, R. Garofalo, C. Carey, R. David, D.L. Meadows, R.P. Stone; Correlating Biocide Uptake and Release Profiles With Corneal Staining and Subjective Symptoms . Invest. Ophthalmol. Vis. Sci. 2005;46(13):915.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To determine if the interactions of lens care preservatives with contact lenses is an important factor in clinical signs and symptoms. Methods: This study evaluated uptake and release profiles of two preservatives used in MPS products, alexidine contained in ReNu® with MoistureLocTM and POLYQUAD® (polyguaternium–1) contained in OPTI–FREE® Express®. Three lens materials were used in a cross over study design: SofLens 66® (alphafilcon A), Acuvue® 2 (etafilcon A) and Acuvue® AdvanceTM (galyfilcon A, with HYDRACLEARTM). Asymptomatic, adapted daily wear soft lens users wore groups I and IV soft hydrophilic or silicone hydrogel lenses for a maximum of 2, 4 and 6 hrs each day. New lenses were dispensed for each wear period. The worn lenses were analyzed for preservative content using HPLC and release profiles calculated. Short–term changes in corneal staining and ocular symptoms were assessed at defined time intervals following lens insertion in order to compare these ocular findings with laboratory uptake and release properties. Results: All three lens types uptake alexidine during an overnight soaking period. The rate of preservative release during wear depended on the lens type. After 2 hours, Acuvue® 2 and SofLens 66® released 67% and 78% of alexidine, respectively. Acuvue® AdvanceTM released 29% of the preservative in two hours. Clinically significant corneal staining was observed at 2 and 4 hours when subjects wore Acuvue® 2 and Acuvue® AdvanceTM lenses soaked in the alexidine–based system. At the 2 hour interval, extent of corneal staining increased in all subjects with Acuvue 2 lenses, and 50% of the subjects with Acuvue Advance lenses. Only minimal staining was observed for SoftLens 66® at 2, 4 and 6 hours. Symptoms were not correlated with the extent of staining. Lenses cycled in the POLYQUAD® – based product showed minimal uptake into lenses and corneal staining was low with all the lens materials tested. Conclusions: The study demonstrated the difference in uptake/release profiles for MPS products preserved with Alexidine or POLYQUAD ® using 3 soft lens materials. For some lens materials these differences in biocide uptake/release appear to be correlated with corneal staining patterns but not symptoms.
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