Safety Profile of Minimally Invasive Glaucoma Surgery

Kateki Vinod; Steven J. Gedde


Curr Opin Ophthalmol. 2021;32(2):160-168. 

In This Article

Suprachoroidal Minimally Invasive Glaucoma Surgery

The CyPass Micro-Stent (Alcon Laboratories, Fort Worth, TX, USA) is a fenestrated 6.35 mm polyimide suprachoroidal shunt that received FDA approval for implantation into the suprachoroidal space during cataract surgery. The pivotal COMPASS trial randomized 505 patients to undergo phaco-CyPass (n = 374) or phaco alone (n = 131) and reported postoperative outcomes through two years.[85] Among the most common transient complications in the phaco-CyPass group were BCVA loss of two or more lines (33; 8.8%), iritis (32; 8.6%), and corneal edema (13; 3.5%), whereas 4 (1.1%) patients had persistent vision loss at two years. Intraocular pressure spikes occurred in 16 (4.3%) patients, and hypotony developed in 11 (2.9%) patients. Cyclodialysis cleft greater than 2 mm was inadvertently created in seven (1.9%) patients but did not result in hypotony or related sequelae. Stent-related adverse events included obstruction from focal PAS (8; 2.1%), malpositioning (2; 0.5%), and migration (2; 0.5%), none of which compromised visual acuity. Sight-threatening complications including suprachoroidal hemorrhage, choroidal effusions, and endophthalmitis did not occur.

The Study to Assess Long-Term Safety of the CyPass Micro-Stent in Patients Completing the COMPASS Trial (COMPASS XT) was a three-year safety extension study that included 282 patients from the original cohort (n = 215 phaco-CyPass group; n = 67 phaco group). Five-year results demonstrated a statistically significant difference in mean endothelial cell density between the phaco-CyPass group (1931.2 cells/mm2) and the phaco group (2189.1 cells/mm2; P < 0.001).[86] Endothelial cell loss was likely related to device positioning, such that visibility of two or more retention rings on the proximal end of the device in the anterior chamber was more likely to be associated with greater endothelial cell loss.[87] In the phaco-CyPass group, three eyes developed focal corneal edema, four eyes underwent trimming of the proximal end of the device, one eye developed new corneal guttae, and one eye demonstrated progression of corneal dystrophy.[86,87] The CyPass Micro-Stent subsequently underwent voluntary market withdrawal by Alcon Laboratories, followed by an FDA Class I recall, in 2018. A task force organized by the American Society of Cataract and Refractive Surgery recommends monitoring patients who have undergone CyPass placement for corneal edema. Trimming of the proximal end of the microstent is advised instead of repositioning or removal in cases of clinically significant corneal edema.[88]