Abstract: Surgery is an important intervention in treatment of glaucoma. In this article, according to the different mechanisms of intraocular pressure (IOP) lowering classifies the surgical procedures into two categories: increasing drainage of aqueous humor and reducing the generation of aqueous humor. Additionally, the basis of the drainage pathways, divides the increasing drainage of aqueous humor type into two subtypes: external drainage and internal drainage which includes Schelemm canal drainage approach and suprachoroidal space drainage approach. Reducing the generation of aqueous humor is divided into three subtypes: cyclophotocoagulation, ultrasond cycloplasty (UCP), cyclocryotherapy. Currently, combined trabeculectomy remains the mainstream procedure of external drainage surgery and various glaucoma drainage devices have been used in clinic. In terms of internal drainage surgery, among the procedures of Schlemm canal drainage approach, internal or external 360°transluminal trabeculotomy, trabeculotomes and microstents have been gradually applied in clinic, and achieve excellent surgical outcome. The safety and efficacy of the implant devices relying on suprachoroidal space drainage approach need further studies. New types of aqueous humor generation reduction procedure are becoming safer and controllable and no longer limited to the treatment of blind advanced glaucoma patient. (Int Rev Ophthalmol, 2021, 45: 273-279)

Key words: glaucoma/surgery, glaucoma filtration surgery, glaucoma drainage device, minimally invasive glaucoma surgery