Ablation of the cornea and synthetic polymers using a UV (213 nm) solid-state laser

A study is made of photoablation of the porcine cornea and synthetic collagen with 213-nm radiation generated by the fifth harmonic from a Q-switched Nd:YAG laser. The new nonlinear crystals, beta barium borate (BBO), with specific angle cutting were used to optimize the fifth-harmonic generation (213 nm). For comparison purposes, the above materials were also ablated by 266-nm (fourth-harmonic) laser radiation. Light and electron microscopy demonstrated that the damage zones created by 213- and 266-nm radiation are <1 and 15 μm, respectively. The ablation similarity between 193 and 213 nm opens major opportunities for the development of a new corneal sculpting system based on solid-state laser technology which will overcome difficulties associated with excimer lasers