Comparison of Protein Extraction from SiH Lens Materials & Care Solutions

Andrew Emch, Karen Lee, Richard Sessler, Kari Green-Chuch, Jason J. Nichols

PURPOSE: To investigate the quantities and identities of protein extracted from two different types of silicone hydrogel contact lenses and several marketed care solutions.

METHODS: Ten silicone hydrogel contact lens wearers were recruited for a two-arm study. In the first arm, subjects wore galyfilcon A (Acuvue Advance, Vistakon) contact lenses on four consecutive days, whereas during the second arm, subjects wore O2 Optix contact lenses (lotrafilcon B, CIBA Vision) on four consecutive days. Each day, subjects applied a new pair of contact lenses to be worn for 8 hours after which, both lenses were then removed from the eyes using forceps (lenses were not rubbed following removal). Lenses were then pooled in one of four commercially available care solutions or one of four protein extraction buffers for a 24 hour soak using a pre-determined randomized sequence. The lenses were then removed and discarded after the soak period. The solubilized protein present in each pooled sample was precipitated, resuspended in water, quantified, and identified using 1-D SDS-PAGE chromatography and nano-LC MS/MS and database sequence bioinformatics.

RESULTS: Passive protein recovery from lenses in arms 1 and 2 was as follows (all quantities are in µg/lens): AQuify (Advance: 0.56, Optix: 3.52), Complete MoisturePlus (Advance: 1.44, Optix: 1.01), OptiFree Express Replenish (Advance: 2.31, Optix: 4.11), and ReNu MoistureLoc (Advance: 1.16, Optix: 3.14). Lactoferrin, lipocalin, and lysozyme were consistently observed across materials and care solutions. Other unique proteins identified included prolactin induced protein, fatty acid binding protein, ifapsoriasin, keratin, and poly Ig receptors.

CONCLUSIONS: For three of the four care solutions, more total protein was removed from O2 Optix than from Acuvue Advance. OptiFree Replenish generally removed the most protein from both lens types compared to the other care solutions. The higher quantities of protein extracted from O2 Optix may be due to stronger protein binding with this material and/or to differences in solution efficacy.