Purchase this article with an account.
M. Suwala, M.–A. Glasier, L. Jones; Activity of Lysozyme Deposited on Conventional and Silicone Hydrogel Contact Lens Materials Using an in vitro Model . Invest. Ophthalmol. Vis. Sci. 2006;47(13):108.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To determine the activity of hen egg lysozyme (HEL) deposited on conventional and silicone hydrogel (SH) contact lens materials using an in vitro model.
Acuvue 2 (etafilcon; AV2), PureVision (balafilcon; PV), Acuvue Advance (galyfilcon; AA), Focus Night & Day (lotrafilcon A; FND) and O2Optix (lotrafilcon B; OPX), Proclear (omafilcon A; PC), and Acuvue OASYS (senofilcon A; AO) contact lenses (n=6) were deposited in vitro in a phosphate–buffered solution (PBS, pH7.4) containing HEL (2mg/ml) for 17 days at 37°C with constant shaking. Lenses were briefly rinsed in PBS to remove unbound material and extracted with 1.5ml of either 50:50 acetonitrile: 0.2% trifluoroacetic acid (AV2, PV, FND, PC, OPX) or 50:50 acetonitrile: 0.02% trifluoroacetic acid (AO, AA). AO, FND, and OPX were also extracted with 1.5ml buffer containing 200µg bovine serum albumin, due to the low mass of protein present. Following lyophilization, extracts were examined for lysozyme activity by micrococcal assay and total protein by Western blot. Lysozyme activity was assessed using standards incubated for 17 days at 37°C and processed as per the in vitro samples.
Lysozyme deposit on AV2 exhibited the greatest activity (91±5%) and this was statistically different from all other lens types (p<0.001). Lysozyme deposit on FND (24±5%) and OPX (23±11%) exhibited the lowest activity. Lysozyme deposit on other lens materials exhibited intermediate activity (AA, 60±15; AO, 51±9; PV, 58±8; and PC, 38±3%). In terms of total protein accumulation, AV2 showed the most, with 1800µg, PC the next with 68µg and FND the least, with 2µg. AA, AO, and OPX accumulated similar amounts of lysozyme, at approximately 6µg.
Silicone hydrogels deposit lower amounts of lysozyme than either conventional Group II (PC) or Group IV (AV2) lenses and the levels of lysozyme denaturation are highly variable between materials.
This PDF is available to Subscribers Only