Glaucoma is a group of diseases affecting the optic nerve that results in vision loss and is frequently characterized by raised intraocular pressure (IOP).

However, because SLT is performed using a laser with much lower power than ALT, it does not appear to affect the structure of the trabecular meshwork (based on electron microscopy) to the same extent, so retreatment may be possible if the effects from the original treatment should begin to wear off, although this has not been proven in clinical studies.

Performed either with standard surgical instruments or a laser, it is typically used to decrease intraocular pressure in patients with angle-closure glaucoma.

This is based on analysing four studies with a sample of 3,086 eyes of 1,543 participants; iridotomy seems to improve gonioscopic findings, but does not show to be clinically significant.

Filtering procedures are typically divided into either penetrating or non-penetrating types depending upon whether an intraoperative entry into the anterior chamber occurs.

[28] Ab externo trabeculectomy (AET) involves cutting from outside the eye inward to reach Schlemm's canal, the trabecular meshwork, and the anterior chamber.

Also known as non-penetrating trabeculectomy (NPT), it is an ab externo (from the outside), major ocular procedure in which Schlemm's canal is surgically exposed by making a large and very deep scleral flap.

[34] Viscocanalostomy is also an ab externo, major ocular procedure in which Schlemm's canal is surgically exposed by making a large and very deep scleral flap.

Scar formation at the site of excision or operation may block aqueous humor circulation, while healthy tissue regeneration will keep newly created drainage channels functional.

A surgical goniotomy involves cutting the fibers of the trabecular meshwork to allow aqueous fluid to flow more freely from the eye.

[48][49] Goniocurretage is an "ab interno" (from the inside) procedure that used an instrument "to scrape pathologically altered trabecular meshwork off the scleral sulcus".

[14] A surgical cyclodialysis is a rarely used procedure that aims to separate the ciliary body from the sclera to form a communication between the suprachoroidal space and the anterior chamber.

[10] A cyclogoniotomy is a surgical procedure for producing a cyclodialysis, in which the ciliary body is cut from its attachment at the scleral spur under gonioscopic control.

As canaloplasty does not require the creation of a bleb, significant long-term risks such as infection and hypotony (extremely low eye pressure) are avoided.

[10] A systematic review seeking to assess the safety and effectiveness of diode transscleral cyclophotocoagulation found one study in Ghana comparing patients who received low-energy versus high-energy variations of the procedure to treat glaucoma.