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R. Rogers, L.W. Jones; In vitro and ex vivo Wettability of Phema and Siloxane–Based Contact Lens Polymers . Invest. Ophthalmol. Vis. Sci. 2005;46(13):918.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Wettability of contact lens materials can impact in–eye comfort. A contact angle measuring device was used to determine the in vitro wettability of daily disposable (DD) and silicone hydrogel (SH) lenses. Ex vivo measurements were made on Etafilcon A following 8 hours of in–eye wear after soaking in various care regimens. Methods: Lens materials (DD: Etafilcon A, Hilafilcon A, Ocufilcon B, Nelfilcon A; SH: Lotrafilcon A, Lotrafilcon B, Galyfilcon A, Balafilcon A) were analysed directly from the packing solution and after soaking in care regimens for 12 hours. Contact angles were also measured after soaking lenses for 5 minutes in saline for 8 cycles to determine the residence time of the regimen and/or packing solution on the lens. Regimens included: Sensitive Eyes® (Bausch & Lomb), Complete® MoisturePLUSTM (Advanced Medical Optics), OPTI–FREE® EXPRESS® (OFX; Alcon), ReNu MultiPlus® (RMP; Bausch & Lomb) and SoloCare® Plus (SCP; CIBA Vision). Results: Lens material and rinsing time significantly impacted contact angles (p<0.001). Initially, Ocufilcon was the least wettable DD (60°). After rinsing, all DD materials rapidly developed high contact angles (>60°). Group II materials (Hilafilcon/Nelfilcon) retained the lowest contact angles. Balafilcon had the highest SH contact angles (115°) through all cycles. Galyfilcon was the most wettable SH initially, but rapidly developed contact angles similar to Balafilcon. Lotrafilcon materials retained the most wettable surfaces (75° – Lotrafilcon A; 50° – Lotrafilcon B). Contact angles of SH lenses were significantly lower after soaking in SCP and OFX. Other solutions had minimal impact on wettability. Acuvue lenses soaked in OFX and examined ex vivo after 8 hours of wear had low contact angles (<10°) compared to lenses soaked in RMP (>80°). Conclusions: SH materials are less wettable than pHEMA–based hydrogels and can be modified by soaking in various care regimens. Contact angle analysis provides valuable data on in vitro and ex vivo wettability of hydrogel polymers and could provide a method for development of materials with more wettable surfaces and in–eye rewetting agents. Study funded by Alcon
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