Effects of femtosecond laser‐assisted trephination on donor tissue in liquid interface as compared to applanated interface

PURPOSE: To evaluate the effects of femtosecond laser‐assisted keratoplasty using a liquid patient interface (L‐PI) as opposed to an applanated interface (A‐PI) on graft quality and functionality markers. METHODS: Pressure measurements during femtosecond laser‐assisted trephination were performed using two groups of 10 porcine eyes. Trephination was performed either in an L‐PI or in an A‐PI setting. Pressure sensor needles placed intravitreally continuously recorded intraocular pressure during trephination. Twenty paired human donor eyes were used to test the morphological quality of donor tissue after trephination in L‐PI and A‐PI settings. Optical coherence tomography (OCT) scans were performed before and after trephination. Images were processed using ImageJ and pixel(2). RESULTS: During trephination, pressure measurements with an L‐PI were significantly lower than with an A‐PI (p = 0.0121). Mean pressure during trephination was 78.1 mmHg ± 37.6 mmHg with L‐PI and 188.6 mmHg ± 17.7 mmHg with A‐PI. Trephination in A‐PI produced a significantly larger increase (p < 0.00001) in donor pachymetry than trephination in L‐PI. Significantly lower areas of Descemet folds were achieved in L‐PI trephination than in A‐PI trephination (p < 0.01). There was no significant difference in circularity between A‐PI and L‐PI (p = 0.27). Total time required for trephination was comparable between L‐PI and A‐PI (p = 0.45). Time taken to reach working vacuum was achieved significantly more quickly in L‐PI (p < 0.05). CONCLUSION: Femtosecond laser‐assisted L‐PI keratoplasty appears to be a promising method to decrease stress to donor and recipient tissue during femtosecond laser‐assisted trephination. Results showed favourable donor tissue morphology markers after L‐PI trephination.