Sclerostomy ab interno using long-wave laser modalities: acute morphological effects.

: Sclerostomy fistulas were created ab interno in cadaver porcine eyes by an active contact method using a 200-microns-diameter silica optical fiber in conjunction with either Ho:YAG-, Nd:YAG-, or diode-laser light, and a qualitative comparison of the degree of collateral thermal damage induced in each case was undertaken at the light and electron microscopic levels. The apparent breadth of coagulated tissue observed in association with cross-sectioned fistula profiles exhibited considerable local variation, irrespective of the radiation source employed; no intrinsic difference in either the intensity or the extent of the thermal insult incurred was noted between the three laser modalities.