Does a YAG Capsulotomy Laser have the wrong parameters for SLT?
If a short pulse width is important, why not use an existing Nd:YAG capsulotomy laser for SLT? While energy levels and pulse widths of YAG lasers might seem appropriate, the small focused spot size of 6 to 10 microns makes the fluence far too high even at the lowest energy settings when compared to the 400 micron spot size of the SLT laser. In addition experiments by Mark Latina, showed that the reduced melanin absorption of the 1.06 micron wavelength YAG laser reduced the selectivity of the effect when compared to 532 nm green light which is more highly absorbed by melanin. Historically Q-switched lasers have been used to attempt trabecular punctures to connect the anterior chamber and Schlemm’s canal to facilitate outflow. Both ruby and YAG laser trapeculoplasty have been reported. Only ALT and now SLT have shown sustained pressure lowering effect from laser trabeculoplasty.
