Holmium laser sclerostomy is a useful surgical procedure in eyes with refractory glaucoma. The success rate is 60%, comparable to the success rate with a seton, but there is a significantly lower rate of complications compared to a seton. Furthermore, the conjunctiva is minimally dissected and less surgical trauma is involved with the procedure, an advantage compared to other filtering operations. The use of a corneascleral flap producing a "guarded" Holmium sclerostomy reduces the incidence of complications and there were no flat or shallow anterior chambers in the 47 eyes operated on and reviewed in this study.