Glaucoma is a leading cause of preventable and irreversible blindness. [1][2][3][4][5] Glaucoma is a chronic and progressive neurodegenerative disorder causing loss of retinal ganglion cells and their axons. 6 Characteristic 'cupping' of the optic disc is seen with corresponding loss of visual field. Elevated intraocular pressure (IOP) is a causative risk factor for the development and progression of glaucoma, and lowering IOP is the mainstay of treatment. Besides IOP, other risk factors are well-known, e.g. age, family history, and race (e.g. African descent). 7 The balance of aqueous humor production (inflow) and drainage (outflow) determines the IOP. The pathophysiology of elevated IOP in primary open-angle glaucoma (POAG) is dysfunctional drainage, specifically through the trabecular meshwork (TM). 8,9 The exact mechanisms that control drainage through the TM are not fully understood, but changes in the extracellular matrix (ECM) are one of the reasons. Furthermore, pathological accumulations of certain ECM structures within the TM have been described as causative in eyes with POAG.In managing glaucoma patients, lowering the IOP is the only available treatment with a significant body of supporting evidence. [10][11][12][13][14][15][16][17][18][19][20] Medical reduction of IOP is the first line of therapy in most cases. 12,21,20 If medical treatment fails, there are several well-established surgical procedures to reduce IOP. Trabeculectomy (TE) as it is performed today was introduced in 1968 byCairns 23 and at the same time by Linner. 24 It is still the gold standard in glaucoma surgery. The aqueous flows via a scleral flap from the anterior chamber into the subconjunctival space. 25 TE is very effective in long-term IOP reduction. 26,27 The use of antimetabolites during surgery provides an even better long-term success. [28][29][30][31][32][33][34] The greatest outflow resistance is at the location of the juxtacanalicular TM (JCT) and inner wall of Schlemm's canal. Schlemm's canal communicates with the episcleral veins. The drainage of aqueous outflow through the TM into Schlemm's canal and later on into the episcleral veins is called the trabecular outflow (83-96 %, 'conventional' pathway), the remaining 5-15 % of the aqueous humor is drained via the uveoscleral pathway ('alternative' pathway). 35,36 The JCT region, which includes the inner wall of Schlemm's canal and the underlying TM, is thought to be the region where regulation of aqueous humor outflow takes place. [37][38][39] The JCT region has the highest resistance to outflow, especially under conditions of elevated IOP. [39][40][41][42] Although TE remains the mainstay of surgical glaucoma treatment, it remains feasible to enhance aqueous outflow through the conventional pathway. Several surgical approaches have been tried, e.g. ab interno TE with the Trabectome™, 43,44 goniotomy, and goniopuncture, which can be performed with or without endoscopy. This paper focuses on another technique, excimer laser trabeculotomy (ELT, also known as excimer laser...