Over the years, there has been significant advancement in the safety and effectiveness of external cyclosurgery for glaucoma. This progress ranges from the initial "cyclodestructive surgery" to modern cycloplasty techniques, expanding beyond end-stage glaucoma treatment. Notably, innovative approaches like micropulse transscleral cycloplasty and ultrasonic cycloplasty are now being employed in earlier stages of glaucoma with better visual acuity, qualifying as minimally invasive procedures. Through a comprehensive review of the historical evolution of external cyclosurgery, elucidation of the mechanisms, clinical outcomes, and potential complications associated with novel cycloplasty techniques, and integration of practical clinical insights, this article aims to furnish clinicians with a profound comprehension of external cyclosurgery for glaucoma.