Abstract
Presbyopia, a prevalent age-related vision disorder, is primarily characterized by the progressive loss of accommodative ability due to crystalline lens hardening, as described by the Helmholtz theory of accommodation. Among emerging presbyopia correction techniques, femtosecond laser lentotomy (fs-lento) has gained attention for its potential to restore accommodative function through the creation of intracapsular gliding planes via laser-induced optical breakdown (LIOB). This approach offers distinct advantages, including potential accommodative recovery, a non-invasive nature, minimal tissue disruption, and negligible bleeding risk. However, despite two decades of technical development, the clinical translation of fs-lento remains hindered by challenges in quality control and outcome heterogeneity, primarily due to the absence of precise quantitative methods for assessing the surgical effects on tissue mechanical properties. To address these limitations, we developed a femtosecond laser ocular research apparatus (FLORA) system for surgical investigations. Furthermore, we implemented a novel PZT-contact optical coherence elastography (OCE) system, modified from SD-OCT and validated through phantom experiments, for quantitative tissue mechanical characterization. Our experimental results using ex vivo porcine lenses demonstrated that the sequential creation of 16 flower-patterned gliding planes (2 × 3 mm(2)) with pulse energy of 4.1 μJ, generating cavitation bubbles <50 μm in diameter, effectively reduced the stiffness from 36.88 ± 1.93 kPa to 31.39 ± 2.11 kPa in the anterior lens OCE measurement region. This study provides the quantitative method of the relationship between fs-lento surgery patterns and resultant biomechanical modifications in lens tissue.