Weissman B A, Gardner K M
Am J Optom Physiol Opt. 1984 Apr;61(4):239-45. doi: 10.1097/00006324-198404000-00003.
We have developed a computer program which allows analysis of soft contact lens flexure without assuming a priori that the posterior surface of the lens aligns with the central anterior cornea. Such analysis leads to the conclusion that thin low-minus lenses entrap tear layers of low volume (about 5.5 microliter) and minimum power, whereas low-plus lens systems can develop tear layers of greater volume (about 9.5 microliter), and significant power (about -2.00 D). The later finding supports clinical impressions that plus lenses "lose" power when placed on the eye. In some cases our data suggest that the lens posterior surface closely aligns with the anterior cornea, whereas in other cases such alignment is unlikely. It also appears that mathematical models for the simultaneous flexure of front and back radii of soft lenses may be described for specific lens designs. This current study suggests that delta r2 congruent to 2 delta r1 describes the relation for low-plus lenses, and delta r2 congruent to 0.75 delta r1 is the relation for low-minus lenses.
我们开发了一种计算机程序，该程序可在不事先假定镜片后表面与中央前角膜对齐的情况下，对软性隐形眼镜的弯曲度进行分析。这种分析得出的结论是，薄的低度数镜片会困住少量（约5.5微升）且低屈光度的泪液层，而低度数的正镜片系统则会形成更大量（约9.5微升）且有显著屈光度（约-2.00 D）的泪液层。后一发现支持了临床上的一种观点，即正镜片戴在眼睛上时会“降低”屈光度。在某些情况下，我们的数据表明镜片后表面与前角膜紧密对齐，而在其他情况下这种对齐则不太可能。似乎还可以针对特定的镜片设计描述软性镜片前后曲率同时弯曲的数学模型。当前的这项研究表明，对于低度数的正镜片，Δr2与2Δr1相等描述了这种关系，而对于低度数的负镜片，Δr2与0.75Δr1相等是这种关系。
