Ab interno trabeculotomy using a Nd : YLF picosecond laser

Background. The outcome of glaucoma surgery is limited by scar formation. A s an alternative to current techniques, the opening of the trabecular meshw ork ab interno may lead to increased outflow. This study examined the Nd:YL F picosecond laser for ab interno ablation of the trabecular meshwork witho ut opening of the eye. Patients and methods. A Nd:YLF picosecond laser was used which allows tissu e to be ablated even through fluids. We performed ablation with different s pot sizes and energies in postmortem eyes. Afterwards the effect of the las er treatment was examined by electron microscopy. Results. The ablation threshold for the cornea was found to be 20 J/cm(2) f or a pulse width of 30 ps. At a lower level of energy (10 J/cm(2)) ablation of the trabecular meshwork was possible. The size of the focus which was l imited by the optics of the slit-lamp was about 50 mum. Conclusion. These initial results with a Nd:YLF picosecond laser confirm th e possibility of ablating tissue in the trabecular meshwork ab interno with out the need to open the eye.