AqueSys Xen implant in primary open-angle glaucoma (POAG): a confocal microscopy and anterior segment OCT

Session Details

Session Title: Glaucoma II

Session Date/Time: Tuesday 08/09/2015 | 08:00-10:30

Paper Time: 09:10

Venue: Room 17

First Author: : R. Spinetta ITALY

Co Author(s): :    V. Aragno   P. Cannizzo   G. Pignata   F. Grignolo   T. Rolle   A. Fea     

Abstract Details

Purpose:

The Aquesys Xen Gel Stent is a new minimally invasive ab interno device, producing a drainage route for the aqueous humor (AH) from the anterior chamber into the subconjunctival space and leading to a formation of a filtering blebs in the nasal conjunctiva. Previous studies used AS imaging techniques to evaluate the bleb in trabeculectomy. The XEN bleb is atypical and very small: imaging could represent an effective mean in the follow-up. Aim of this study is to provide a microscopic and macroscopic analysis by in vivo confocal microscopy (IVCM) and anterior segment OCT (AS-OCT) of the XEN filtering bleb.

Setting:

Department of Surgical Sciences, Ophthalmic Clinic, University of Turin, Turin, Italy.

Methods:

The device was implanted in 12 eyes of 12patients (mean age72±10years) affected by uncontrolled POAG with maximal medical therapy. Intraocular pression(IOP), bleb morphology at slitlamp, IVCM and the AS-OCT of the conjunctiva were assessed preoperative and 3months postoperatively. Mean density (MMD,cysts/mm2) and mean area(MMA,µm2) of conjunctival microcysts and density of connective subepithelial stromal fiber patterns were evaluated by IVCM and quantified by means of ImageJ software. Appropriate placement of the device, bleb wall reflectivity and HA dreinage were assessed by AS-OCT. Complete success was defined as a IOP<18 mHg, qualified IOP<18 mmHg on medication, unsuccess IOP>18mmHg on medication.

Results:

3months after surgery, the success was complete in10 eyes (83%), qualified in 1eye (8.3%) and unsuccessful in 1 eye (8.3%). Mean IOP decreased from 21,8±2,8 mmHg to 14,1±5,2mmHg (p=0,00017). Mean MMD increased from 7,64±15,12cysts/mm2 to 56,75±44,9cysts/mm2(p=0,02) and mean MMA increased from 773,34±1361,6µm2 to 15564,93±12264,07 µm2(p=0,0007) in the nasal conjunctiva. Microcysts showed a clustered pattern in contrast with the diffuse pattern found in the preoperative. In the central and temporal conjunctiva these parameters didn't show significantly differences. Mean stromal density was slightly decrease but without statisticaly significance (p=0,4). The AS- OCT demonstrated the appropriate placement of the device in all eyes.

Conclusions:

Conjunctival microcyst tended to increase in density and area after succesfull implantation. These microscopic changes indicate an enhanced AH outflow across the sclera and the conjunctiva located at the site of surgery. These findings correlate with other studies results on differents filtration surgeries (i.e. trabeculectomy, gold microshunt and canaloplasty)indicating that our results are encouraging. Both IVCM and AS-OCT can be used as non invasive means to evaluate the bleb function in XEN implant. Due to the small size of the XEN bleb, IVCM and AS-OCT can be potential instrument to evaluate the bleb health and guide needling procedures when appropriate.

Financial Interest:

NONE