Purpose: To evaluate the endothelial cell survival and stromal bed quality when creating deep stromal cuts with a low-pulse energy, high-frequency femtosecond laser to produce "ultrathin" tissue for Descemet stripping automated endothelial keratoplasty.
Methods: Seventeen corneas were used for this study. Five corneas were cut with the laser at a depth of 420 to 500 μm to produce a tissue thickness of approximately ≤70 μm. Five corneas served as an uncut comparison group. Vital dye staining and computer digitized planimetry analysis were performed on these corneas. The 7 remaining corneas were cut for scanning electron microscopy evaluation.
Results: The mean central posterior stromal thickness of cut corneas was 60.6 μm (range, 43-72 μm). Endothelial cell damage in cut and comparison corneas was 3.92% ± 2.22% (range, 1.71%-6.51%) and 4.15% ± 2.64% (range, 1.21%-7.01%), respectively (P = 0.887). Low-magnification (×12) scanning electron microscopy revealed a somewhat irregular-appearing surface with concentric rings peripherally. Qualitative grading of higher magnification (×50) central images resulted in an average score of 2.56 (between smooth and rough).
Conclusions: Ultrathin tissue for Descemet stripping automated endothelial keratoplasty can be safely prepared with minimal endothelial cell damage using a low-pulse energy, high-frequency femtosecond laser; however, the resulting stromal surface quality may not be optimal with this technique.