Harris M G, Gale B, Gansel K, Slette C
Am J Optom Physiol Opt. 1987 Apr;64(4):269-73. doi: 10.1097/00006324-198704000-00007.
It has been shown previously that thin polymethyl methacrylate (PMMA), cellulose acetate butyrate (CAB), and Polycon I contact lenses flex on toric corneas. We investigated the flexure and induced residual astigmatism of two gas permeable contact lens materials, Paraperm O2 and Boston II, and compared the results with those of other materials. Six subjects (12 eyes) with corneal toricities ranging from 1.75 to 3.25 D wore five Paraperm O2 lenses and five Boston II lenses with center thicknesses ranging from 0.10 to 0.20 mm. Flexure and induced residual astigmatism were measured on all corneas wearing all lenses in a double-masked fashion. All lenses studied showed flexure and induced residual astigmatism, which increased as center thickness decreased. For both lens types, lenses thinner than 0.15 mm flexed significantly more than thicker lenses. This critical center thickness should be considered when fitting these lens types on toric corneas.
先前已表明，薄的聚甲基丙烯酸甲酯（PMMA）、醋酸丁酸纤维素（CAB）和Polycon I隐形眼镜在复曲面角膜上会发生弯曲。我们研究了两种透气隐形眼镜材料Paraperm O2和Boston II的弯曲情况及诱导产生的残余散光，并将结果与其他材料进行了比较。六名角膜散光在1.75至3.25 D之间的受试者（12只眼）佩戴了五片中心厚度在0.10至0.20 mm之间的Paraperm O2镜片和五片Boston II镜片。以双盲方式测量了所有佩戴镜片的角膜的弯曲情况及诱导产生的残余散光。所有研究的镜片均显示出弯曲及诱导产生的残余散光，且随着中心厚度的减小而增加。对于这两种镜片类型，厚度小于0.15 mm的镜片比厚镜片弯曲得更明显。在给复曲面角膜佩戴这些镜片类型时，应考虑这个临界中心厚度。
