Biomechanical Effects Of Femtosecond Laser-Induced 3D Two-Photon Cross-Linking On Smile-Derived Corneal Lenticules
Published 2026 - 44th Congress of the ESCRS
Reference: FP02.15 | Type: Free paper | DOI: 10.82333/fv8m-v219
Authors: Ms Xinjie Zhu* 1 , Mr Chenxu Wang 2 , Dr Yang Shen 3 , A/Prof. Xiaoying Wang 3 , A/Prof. Yun-Lu Sun 2
1Eye Ear Nose and Throat Hospita,Shanghai,China, 2College of Future Information Technology,Fudan University,Shanghai,China, 3Eye Ear Nose and Throat Hospita,Shanghai,China;National Health Commission Key Lab of Myopia,Fudan University,Shanghai,China;Shanghai Research Center of Ophthalmology and Optometry,Shanghai,China
Purpose
To investigate the effects of near-infrared (NIR) femtosecond laser two-photon cross-linking (2P-CXL) on the microstructural, biomechanical, and optical properties of corneal stromal lenticules derived from Small Incision Lenticule Extraction (SMILE).
Setting
Ex vivo, self-controlled laboratory study.
Methods
Forty SMILE-derived corneal stromal lenticules were collected and bisected: one half received spatial 3D 2P-CXL treatment (experimental group), while the contralateral half served as the blank control. Three experimental subgroups were established based on low, medium, and high laser energy and scanning parameters. Pre- and post-processing assessments included: macroscopic Young's modulus (uniaxial tensile testing), visible light transmittance (spectrophotometry), and ultrastructural changes in collagen fiber networks and molecular composition (hematoxylin-eosin [HE] staining, transmission electron microscopy [TEM], and Raman spectroscopy).
Results
Post-2P-CXL, Young's modulus significantly increased (9.90 ± 1.24 MPa vs. 7.39 ± 0.86 MPa; t = 12.85, P < 0.001). The degree of mechanical enhancement was highly parameter-dependent, with mean increases of 1.430 ± 0.185 MPa (t = 9.924, P < 0.001) in the low-energy group, 2.448 ± 0.528 MPa (t = 17.00, P < 0.001) in the medium-energy group, and 3.653 ± 0.498 MPa (t = 25.36, P < 0.001) in the high-energy group. HE/TEM revealed significant ultrastructural densification of the collagen fiber network and reduced interfibrillar spacing. Raman spectroscopy showed consistent characteristic peak positions with decreased corresponding intensities. No significant difference in transparency was found (74.5 ± 2.91% vs. 75.0 ± 2.66%; t = 1.279, P = 0.20).
Conclusions
NIR femtosecond laser two-photon cross-linking enables significant, controllable, and customizable mechanical enhancement of corneal lenticules through ultrastructural densification without compromising optical transparency. This technology provides a novel approach for personalized processing of stromal lenticules and expands their potential clinical applications.