Efron Nathan, Morgan Philip B, Cameron Ian D, Brennan Noel A, Goodwin Marie
Institute of Health and Biomedical Innovation, and School of Optometry, Queensland University of Technology, Kelvin Grove, Australia.
Optom Vis Sci. 2007 Apr;84(4):328-37. doi: 10.1097/OPX.0b013e31804375ed.
To measure the oxygen permeability (Dk) and water content (WC) of silicone hydrogel (Si-Hy) contact lens materials.
Randomized and masked determinations of the Dk of 5 Si-Hy and two hydrogel materials were made using a modified version of the polarographic measurement method described in ISO 9913-1. Stacks of one to six parallel-sided contact lenses (all -1.00 DS) were evaluated, with each stack measured at least twice. The resulting value for t/Dk was plotted against the thickness (t) of each stack, with Dk calculated as the inverse of the gradient of this relationship. This methodology corrects for boundary effects. A mathematical calculation was used to correct for edge effects. Gravimetric determination of lens WC was conducted at room temperature and 35 degrees C.
Measured values (+/-95% CI) of Dk, and WC at room temperature, with manufacturer-claimed values in parentheses, were Focus Night and Day: Dk 162.0 +/- 9.8 (140), WC 23.0 +/- 3.2 (24); Acuvue Oasys: Dk 107.4 +/- 7.4 (103), WC 36.9 +/- 1.0 (38); O2 Optix: Dk 80.5 +/- 4.9 (110), WC 32.1 +/- 1.2 (33); PureVision: Dk 75.9 +/- 6.6 (91), WC 35.8 +/- 1.3 (36); Acuvue Advance: Dk 75.2 +/- 9.8 (60), WC 46.5 +/- 1.1 (47); 1. Day Acuvue: Dk 21.0 +/- 1.0 (21.4), WC [not measured] (58); and Seequence: Dk 8.2 +/- 0.7 (8.5), WC 36.6 +/- 2.7 (38).
Claimed Dk values for Acuvue Oasys and the two reference hydrogel materials fell within the 95% confidence interval of our measured values. Our measurements of Dk for the other four Si-Hy lenses were not in agreement with claimed values. There is a general inverse relation between Dk and WC (both at 35 degrees C) for Si-Hy lenses. Our modified polarographic methodology can be successfully employed for measuring the Dk of Si-Hy materials.
测量硅水凝胶（Si-Hy）隐形眼镜材料的透氧性（Dk）和含水量（WC）。
采用ISO 9913-1中所述极谱测量方法的改进版本，对5种硅水凝胶材料和两种水凝胶材料的Dk进行随机和盲法测定。评估由一至六个平行边隐形眼镜（均为-1.00 DS）组成的堆叠，每个堆叠至少测量两次。将所得的t/Dk值与每个堆叠的厚度（t）作图，Dk计算为此关系梯度的倒数。该方法校正了边界效应。采用数学计算校正边缘效应。在室温和35摄氏度下对镜片的WC进行重量法测定。
室温下Dk和WC的测量值（±95%CI），括号内为制造商声称的值，分别为：Focus Night and Day：Dk 162.0±9.8（140），WC 23.0±3.2（24）；Acuvue Oasys：Dk 107.4±7.4（103），WC 36.9±1.0（38）；O2 Optix：Dk 80.5±4.9（110），WC 32.1±1.2（33）；PureVision：Dk 75.9±6.6（91），WC 35.8±1.3（36）；Acuvue Advance：Dk 75.2±9.8（60），WC 46.5±1.1（47）；1. Day Acuvue：Dk 21.0±1.0（21.4），WC[未测量]（58）；以及Seequence：Dk 8.2±0.7（8.5），WC 36.6±2.7（38）。
Acuvue Oasys和两种参比水凝胶材料的声称Dk值落在我们测量值的95%置信区间内。我们对其他四种硅水凝胶镜片的Dk测量值与声称值不一致。对于硅水凝胶镜片，Dk和WC（均在35摄氏度下）之间存在普遍的反比关系。我们改进后的极谱方法可成功用于测量硅水凝胶材料的Dk。
