In vivo analysis of conjunctiva in gold micro shunt implantation for glaucoma

To describe the conjunctival epithelial features seen with in vivo confocal microscopy (IVCM) after gold micro shunt (GMS) implantation in the suprachoroidal space, in patients with uncontrolled glaucoma.

This was an observational case series study. Fourteen eyes of 14 consecutive glaucomatous patients with a history of multiple failed incisional surgeries followed by GMS implantation were evaluated with a digital confocal laser-scanning microscope (HRT II Rostock Cornea Module). Patients were divided into two groups: successful implantations (Group 1: eight patients, eight eyes), defined as a one-third reduction in preoperative intraocular pressure (IOP) with or without antiglaucoma medications and failed implantations (Group 2: six patients, six eyes) as a less than one-third reduction in preoperative IOP with maximal tolerated medical therapy. The examination was performed from 3 to 20 months (mean 15.4±5.4) postoperatively. Conjunctival mean microcyst density (MMD: cysts/mm(2)) and mean microcyst area (MMA: μm(2)) were the main outcome measurements.

The mean postoperative IOP was statistically different between the two groups (p<0.05), with the values of 14.3±2.77 and 32.3±8.01 mm Hg in Groups 1 and 2, respectively. When comparing successful with failed implantation, the IVCM analysis showed a greater MMD (p<0.01) and MMA (p<0.01). Clinical evidence of filtering bleb was not found in any of the patients.

Successful GMS implantation significantly increased conjunctival microcysts density and surface at the site of the device insertion. These findings suggest that the enhancement of the aqueous filtration across the sclera may be one of the possible outflow pathways exploited by the shunt.