Argon laser trabeculoplasty and Nd-YAG laser treatment of the trabecular meshwork

Much progress has been made in understanding basic laser-tissue reaction of the argon and Nd:YAG lasers. Although the lasers are different, they both exert biological as well as mechanical effects on the trabecular meshwork and adjacent tissues. The argon laser is a photocoagulator effecting the TM by heat dissipation, denaturation, and collagen contraction; whereas the Nd:YAG laser is a photodisruptor causing tissue disintegration by mini-blast and shock wave formation. The argon laser produces a localised impermeable scar and stimulates the non-lasered areas to improve aqueous outflow. The Nd:YAG laser causes extensive trabecular damage with subsequent fibrotic response and scarring at the laser site. Both lasers cause trabecular inflammation, may stimulate remaining trabecular cells, and promote an extension of corneal endothelium over the scar. More studies are needed to better understand tissue reaction after laser applications.