6533b838fe1ef96bd12a4887

RESEARCH PRODUCT

Irregularity of the posterior corneal surface during applanation using a curved femtosecond laser interface and microkeratome cutting head.

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PURPOSE: To evaluate the irregularity of the posterior corneal surface and intrastromal dissection during the preparation of donor tissue for Descemet stripping automated endothelial keratoplasty (DSAEK) using a curved interface femtosecond laser and microkeratome. METHODS: Sixteen human donor corneas unsuitable for transplantation were divided into two groups: a femtosecond (FS) laser group (n=7) using the VisuMax femtosecond laser (Carl Zeiss Meditec) and a microkeratome group (n=9) using the Amadeus II microkeratome (Ziemer Ophthalmic Group). The corneas were fixed on artificial anterior chambers. Horizontal cross-sections were obtained using spectral-domain optical coherence tomography prior to applanation, during applanation, as well as during and after intrastromal dissection at 450-μm corneal depth. The posterior surface and the dissection line were evaluated for irregularity by fitting a second-order polynomial curve using regression analysis and obtaining the root-mean-square error (RMSE). Groups were compared using analysis of variance. RESULTS: The RMSE of the posterior surface prior to applanation was 9.7±3.1 μm in the FS laser group and 10.2±2.3 μm in the microkeratome group. The RMSE increased to 50.7±9.4 μm and 20.9±6.1 μm during applanation and decreased again to 10.6±1.4 μm and 8.1±1.8 μm after applanation in the FS laser and microkeratome groups, respectively. The RMSE of the intrastromal cut was 19.5±5.7 μm in the FS laser group and 7.7±3.0 μm in the microkeratome group ( P <.001). CONCLUSIONS: Our results show significantly greater irregularity with the curved interface femtosecond laser–assisted cleavage compared to microkeratome-assisted corneal dissection, possibly due to applanation-derived deformation of the posterior cornea.