Biomechanical Changes And Associated Factors Of Preserved Smile-Derived Corneal Stromal Lenticules

To investigate the biomechanical changes and associated factors of SMILE-derived lenticules under various preservation conditions.

In this study, 520 lenticules of 260 patients who underwent SMILE surgery in the Eye and ENT Hospital of Fudan University (Shanghai, China) from January 2023 to June 2023 were recruited. Lenticules extracted from SMILE operation were immediately put into glycerol, silicone oil, Optisol GS and preserved for 1 day, 1 week and 1 month. Glycerol and silicone oil group were stored at room temperature, while Optisol group at 4℃ and cryopreservation at -80℃. 

A total of 520 corneal stromal lenticules of 260 patients (male: female 98:162, age 28.54±5.98 years, mean spherical error -4.47±1.63 D) were derived during small incision lenticule extraction (SMILE) surgeries, and were stored in glycerol, silicone oil, Optisol and cryopreservation for 1 day, 1 week or 1 month. Spherical error, cylindrical error as well as other main parameters were evaluated. Piuma Chiaro Nanoindenter System (Optics11, Amsterdam, Netherlands) was used to measure the effective Young’s modulus of each lenticule. Changes of effective Young’s modulus were evaluated in each group among all time points.

The effective Young’s moduli of lenticules were largest in glycerol and silicone oil group when preserved for 1 day (P < 0.01*), while in Optisol (P < 0.01*) and cryopreservation (P = 0.03*) group for 1 month. Lenticules preserved in glycerol showed best effective Young’s modulus for 1 day, in silicone oil for 1 week, and in Optisol for 1 month (P < 0.01*). Among all factors observed, the spherical error of SMILE-derived lenticules was a positive influencing factor on its biomechanics (P = 0.04*). 

Glycerol is an ideal preservation method for SMILE-derived lenticules to maintain biomechanical stability in short term. Thickness is a positive influencing factor on the biomechanics of SMILE-derived lenticules.