Cheng Zhenzhou, Zhang Nan, Chang Le, Qi Pengfei, Zhang Lin, Lin Lie, Wang Yan, Liu Weiwei
Institute of Modern Optics, Eye Institute, Nankai University, Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin, China.
Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin, China.
J Biophotonics. 2023 Feb;16(2):e202200160. doi: 10.1002/jbio.202200160. Epub 2022 Oct 4.
Myopia and keratoconus have become common corneal diseases that threaten the quality of human vision, and keratoconus is one of the most common indications for corneal transplantation worldwide. Collagen crosslinking (CXL) using riboflavin and ultraviolet A (UVA) light is an effective approach for treating ophthalmic disorders and has been shown clinically not only to arrest further progression of keratoconus but also to improve refractive power for cornea. However, CXL surgery irradiated by UVA has various potential risks such as surface damage and endothelial cell damage. Here, near-infrared femtosecond laser-based two-photon CXL was first applied to ex vivo human corneal stroma, operating at low photon energy with high precision and stability. After two-photon CXL, the corneal stiffness can be enhanced by 300% without significantly reducing corneal transparency. These findings illustrate the optimized direction that depositing high pulses energy in corneal focal volume (not exceeding damage threshold), and pave the way to 3D CXL of in vivo human cornea with higher safety, precision, and efficacy.
近视和圆锥角膜已成为威胁人类视力质量的常见角膜疾病，圆锥角膜是全球范围内最常见的角膜移植适应症之一。使用核黄素和紫外线A（UVA）光的胶原交联（CXL）是治疗眼科疾病的有效方法，临床研究表明，它不仅能阻止圆锥角膜的进一步发展，还能改善角膜的屈光力。然而，UVA照射的CXL手术存在各种潜在风险，如表面损伤和内皮细胞损伤。在此，基于近红外飞秒激光的双光子CXL首次应用于离体人类角膜基质，以低光子能量运行，具有高精度和稳定性。双光子CXL后，角膜硬度可提高300%，而不会显著降低角膜透明度。这些发现阐明了在角膜焦体积中沉积高脉冲能量（不超过损伤阈值）的优化方向，并为体内人类角膜的三维CXL提供了更高的安全性、精度和有效性。
