Solid state ultraviolet laser (213 nm) ablation of the cornea and synthetic collagen lenticules

We used a Q‐switched Nd:YAG laser with non‐linear optical crystals to produce the 5th (213 nm) and the 4th (266 nm) harmonic frequencies. Using these two wavelengths, we ablated fresh porcine corneas and type I collagen synthetic epikeratoplasty lenticules. For the 213‐nm ablation, radiant exposure was 1.3 J/cm2. The ablation rate was 0.23 μm per pulse for the epikeratoplasty lenticules. We examined all tissues with light microscopy, transmission electron microscopy, and scanning electron microscopy. Histology for the 213‐nm ablation showed a clean ablation crater with minimal collagen lamellae disruption and a damage zone less than 1μm. In comparison, the 266 nm radiation showed more charring at the edges with a damage zone approximately 25 μm deep with disruption of the stromal lamella. Our results show that this solid state UV laser is a potential alternative to the excimer laser for cornea surgery.