Glaucoma is a heterogeneous condition that leads to damage of the optic nerve and visual field loss. The World Health Organization (WHO) ranks glaucoma as the second most common cause of blindness after cataract, and as the leading cause of irreversible blindness affecting about 80 million people worldwide. Gonioscopically, glaucoma is classified into open-angle glaucoma and closed-angle glaucoma. A closed-angle is an anatomical configuration in which there is a mechanical blockage of the trabecular meshwork by the peripheral iris. Etiologically, it can be classified as primary or secondary angle closure. Primary angle closure is not associated with any other ocular condition, while secondary angle closure is associated with one or more other ocular conditions. Chronic angle-closure can occur with or without symptoms, and thus it can be described as ''silent" closed-angle glaucoma. Because this condition mainly consists of irido-trabecular contact leading to synechiae formation and subsequent angle closure.
Patients with advanced glaucoma, defined as near total cupping of the optic nerve with or without severe visual field (VF) loss within 10° of fixation.
According to clinical guidelines of royal college of ophthalmologists Clear lens extraction / phacoemulsification is superior to PI and is advised as primary intervention in PACG.
Phacoemulsification clear lens extraction/cataract surgery is preferred to trabeculectomy and phaco-trab in PACG on the basis of safety, but trabeculectomy or phacotrabeculectomy may be considered for severe disease.
Nowadays non-penetrating glaucoma surgery became more favorable by many surgeons and patients due to its safety and efficacy.