STTR Phase II: Refractive correction using non-invasive laser-induced refractive index change

这一小型企业创新研究第二阶段项目使下一代用于视力矫正的隐形眼镜得以开发，该隐形眼镜基于一种名为“激光诱导折射率变化(LiRIC)”的新型光固化技术。全球超过23亿人患有视觉系统的屈光不正，而超过5亿人没有足够的机会进行屈光矫正。戴眼镜是矫正屈光的一种选择，但戴眼镜可能会受到实际限制，甚至会受到社会的耻辱，尤其是在青少年中。同时，隐形眼镜的视力矫正仅限于其光学处方取决于其厚度分布的镜片。这对视觉质量、眼睛稳定性和角膜健康都有负面影响。这项研究代表了视觉矫正应用方式的根本性转变，因为它改变了光学材料的折射率，使以前无法在薄而稳定的隐形眼镜中使用视觉矫正器。Liric使用高重复频率的飞秒激光对局部介质进行微调，以在水凝胶和活体角膜中产生定制的屈光矫正。LiRIC的工作原理是在眼球材料中积累局部的折射率(RI)变化，以创建折射横向梯度折射率透镜。使用LiRIC而不是表面形状来改变折射率可以为视力矫正带来几个根本性的进步，对视力护理具有深远的影响：1)可以专门为患者制造适合和稳定的隐形眼镜，其屈光矫正与镜片形状分离；2)可以更容易地写入困难和不规则的屈光矫正(即，对于不规则散光、老花眼和更高阶像差)；3)与现有方法相比，可以使用多聚焦和衍射光学设计来进行老花眼和黄斑变性矫正。患者通过Liric镜片观看，这是在第一阶段创造的，其视觉表现(视力和对比敏感度)与对照镜片相当。第二阶段工作的目标是证明Liric在隐形眼镜中以商业制造所需的工艺速度工作。这项工作的目标是演示6.5 mm光学区可以在15秒内成功处理。为了有效地做到这一点，LiRIC工艺必须在超过10米/秒的激光扫描速度下实现多于1波的相变(在555 nm波长)。

This Small Business Innovation Research Phase II project enables the development of the next generation of contact lenses for vision correction based on a novel photomodification technique called "LIRIC (Laser Induced Refractive Index Change)." More than 2.3 billion people world-wide suffer from refractive error in their visual system, while over 500 million have inadequate access to refractive correction. Glasses are an option for refractive correction, however there can be practical limitations and even social stigma associated with wearing glasses, particularly among adolescents. Meanwhile vision correction with contact lenses is limited to lenses whose optical prescription is determined by their thickness profile. This has negative consequences for visual quality, on-eye stability and corneal health. The research represents a fundamental shift in how vision correction is applied because it alters the refractive index of an optical material, enabling previously unavailable visual correctors in thin, stable contact lenses. LIRIC uses a high repetition rate, femtosecond laser to micro-modify the local medium to produce custom refractive corrections in hydrogels, and in living cornea. LIRIC works by accumulating localized refractive index (RI) changes in an ocular material to create a refractive lateral gradient index lens. Changing the refractive index using LIRIC instead of the surface shape can lead to several fundamental advances for vision correction, with profound implications for vision care: 1) contact lenses can be manufactured specifically for patient fit and stability with the refractive correction decoupled from the lens shape; 2) difficult and irregular refractive corrections (i.e. for irregular astigmatism, presbyopia, and higher order aberrations) could be written more easily and with better spatial resolution than with existing methods; 3) multifocal and diffractive optical designs can be utilized for presbyopic and macular degenerative corrections. Patients viewing through LIRIC lenses, created in Phase I, had visual performance (visual acuity and contrast sensitivity) on par with a control lens. The objective of the Phase II work is to demonstrate that LIRIC works in contact lenses at process speeds necessary for commercial manufacturing. The goal of this work is to demonstrate that a 6.5 mm optical zone can be successfully processed in 15 seconds. To effectively do so, the LIRIC process has to achieve more than 1 wave of phase change (at 555 nm wavelength) at laser scanning velocities in excess of 10 meter/second.