Cyclodestructive Procedures in Glaucoma: A Review of Current and Emerging Options

Abstract

The first surgical modalities to reduce aqueous humor production by damaging the ciliary body date back to the early twentieth century. Until recently, however, cyclodestructive procedures (e.g., cyclocryotherapy and transscleral diode laser photocoagulation) have been reserved as last option procedures in refractory glaucoma patients with poor visual potential. Emerging technologic innovation has led to the development of promising, safer and less destructive techniques, such as micropulse diode cyclophotocoagulation, endoscopic cyclophotocoagulation and ultrasound cyclodestruction. Consequently, an emerging paradigm shift is under way with the selection of these surgical options in eyes with less severe glaucoma and good visual potential. Although existing evidence has not, as yet, adequately defined the role and value of these procedures, their emergence is a welcome expansion of available options for patients with moderate-to-severe glaucoma. This article reviews the pertinent evidence on both established and evolving cyclodestructive techniques and describes their growing role in the management of glaucoma.

Keywords: Cyclocryotherapy; Cyclodestruction; Cyclophotocoagulation; Diode laser; Endoscopic photocoagulation; High-intensity focused ultrasound; Micropulse diode; Ophthalmology; Refractory glaucoma; Ultrasound cyclodestruction.

Fig. 1

Thermal modelization for ultrasound cyclocoagulation high-intensity focused ultrasound (HIFU) and trans-scleral cyclophotocoagulation (TSCPC). The temperature evolution curves show that thermal variability is smaller with HIFU. Permission to use this figure was granted by EyeTechCare SA

Fig. 2

Histologic preparation (left) and scanning electron microscopy images (middle and right) of an untreated area of rabbit ciliary processes covered by epithelial cells, which serve to secrete aqueous humor. Red square in the middle photograph indicates the magnified area shown in the right photograph. Permission to use this figure was granted by EyeTechCare SA

Fig. 3

Histologic preparation (left) and scanning electron microscopy images (middle and right) following ultrasound cyclocoagulation. Red square in middle photograph indicates the magnified area shown in the right photograph. The epithelial cell layer is removed but the stromal base is preserved with no explosion of ciliary processes. Permission to use this figure was granted by EyeTechCare SA

Fig. 4

View during endoscopic cyclophotocoagulation. Treated ciliary process has shrunk and appears gray (upper part of image). From the archive of Dr. Brian A. Francis