Rodriguez-Vallejo Manuel, Benlloch Josefa, Pons Amparo, Monsoriu Juan A, Furlan Walter D
Centro de Tecnologías Físicas, Universitat Politècnica de València , Valencia , Spain and.
Curr Eye Res. 2014 Dec;39(12):1151-60. doi: 10.3109/02713683.2014.903498. Epub 2014 Apr 21.
To test multizone contact lenses in model eyes: Fractal Contact Lenses (FCLs), designed to induce myopic peripheral refractive error (PRE).
Zemax ray-tracing software was employed to simulate myopic and accommodation-dependent model eyes fitted with FCLs. PRE, defined in terms of mean sphere M and 90°-180° astigmatism J180, was computed at different peripheral positions, ranging from 0 to 35° in steps of 5°, and for different pupil diameters (PDs). Simulated visual performance and changes in the PRE were also analyzed for contact lens decentration and model eye accommodation. For comparison purposes, the same simulations were performed with another commercially available contact lens designed for the same intended use: the Dual Focus (DF).
PRE was greater with FCL than with DF when both designs were tested for a 3.5 mm PD, and with and without decentration of the lenses. However, PRE depended on PD with both multizone lenses, with a remarkable reduction of the myopic relative effect for a PD of 5.5 mm. The myopic PRE with contact lenses decreased as the myopic refractive error increased, but this could be compensated by increasing the power of treatment zones. A peripheral myopic shift was also induced by the FCLs in the accommodated model eye. In regard to visual performance, a myopia under-correction with reference to the circle of least confusion was obtained in all cases for a 5.5 mm PD. The ghost images, generated by treatment zones of FCL, were dimmer than the ones produced with DF lens of the same power.
FCLs produce a peripheral myopic defocus without compromising central vision in photopic conditions. FCLs have several design parameters that can be varied to obtain optimum results: lens diameter, number of zones, addition and asphericity; resulting in a very promising customized lens for the treatment of myopia progression.
在模型眼中测试多区隐形眼镜：分形隐形眼镜（FCL），其设计目的是诱发近视性周边屈光不正（PRE）。
使用Zemax光线追踪软件模拟佩戴FCL的近视和与调节相关的模型眼。PRE根据平均球镜度M和90° - 180°散光J180来定义，在不同周边位置（从0到35°，步长为5°）以及不同瞳孔直径（PD）下进行计算。还分析了隐形眼镜偏心和模型眼调节时的模拟视觉性能以及PRE的变化。为作比较，使用另一种用于相同预期用途的市售隐形眼镜：双焦点（DF）进行相同的模拟。
当两种设计针对3.5毫米PD进行测试时，无论镜片是否偏心，FCL产生的PRE均大于DF。然而，两种多区镜片的PRE均取决于PD，对于5.5毫米的PD，近视相对效应显著降低。隐形眼镜的近视性PRE随着近视屈光不正的增加而降低，但这可以通过增加治疗区的度数来补偿。FCL在调节的模型眼中也诱发了周边近视性偏移。关于视觉性能，对于5.5毫米的PD，在所有情况下相对于最小弥散圆均出现近视欠矫。由FCL的治疗区产生的重影比相同度数的DF镜片产生的重影更暗。
FCL在明视条件下产生周边近视性离焦而不损害中心视力。FCL有几个可变化的设计参数以获得最佳效果：镜片直径、区数、附加度数和非球面性；从而产生一种非常有前景的用于治疗近视进展的定制镜片。
