Significant intraocular pressure (IOP) reductions were achieved after subTenon placement of an implanted, intraocular pressure-lowering device, inserted using an open conjunctival approach, according to findings published in the Journal of Glaucoma. The procedure resulted in a posterior episcleral fluid (PEF) lake bleb morphology. 

Investigators reviewed the medical records of 26 eyes of 24 patients (mean age 69.4 years, 58% women) who underwent Xen (Allergan Inc.) gel stent implantation at the New York Eye and Ear Infirmary of Mount Sinai through 2018. All surgeries were performed by a single surgeon using the same open conjunctival technique. Bleb morphology was assessed up to 12 months by anterior segment optical coherence tomography (AS-OCT).

Patients were mostly White (54%), 50% of eyes were right eyes, 54% of eyes had primary open-angle glaucoma, 27% had pseudoexfoliation, 15% had chronic angle-closure, and 4% had normal tension glaucoma.


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Of the eyes reviewed, 10 underwent previous laser trabeculoplasty, 8 had phacoemulsification, 4 underwent trabeculectomy (n=4), 1 had prior Descemet stripping endothelial keratoplasty, and another 1 had undergone cryotherapy for a retinal hole.

The average preoperative IOP was 28.1 mm Hg (range, 14 mm Hg to 50 mm Hg) and patients were taking approximately 3.5 (range, 2-5) glaucoma medications. At postoperative day 1, IOP and the number of medications decreased significantly (both P <.01). At month 12, the mean IOP was 12.9±4.0 mm Hg (P <.01) and the number of medications was 0.3±0.6 (P <.01). Complete success was achieved by 60%.

The most common operative complications were hypotony (27%) and hyphema (23%). Needling was required by 2 eyes and 1 of the eyes required 2 needling procedures.

Among eyes with AS-OCT data, 22 of the 24 had functional blebs. Functional blebs had an episcleral cavity, denoted as the PEF lake. The height of the lake increased in size from 231.2±138.1 μm at ≤3 months to 601.0±85.2 μm at >24 months.

The blebs had differing characteristics and were difficult to group together based on characteristics. Eyes were separated into early (n=13), intermediate (n=13), and late (n=4) groups. Late blebs were larger than intermediate, which were larger than early. The majority of early and intermediate eyes had low to medium internal reflectivity and late eyes had medium to high reflectivity.

The 2 eyes with nonfunctional blebs had extensive scarring with no evidence of filtering.

This study was limited as it was an observational study with no standardization of medications and no comparisons with other surgical techniques.

These data indicated that subTenon placement of the gel stents significantly reduced IOP and led to favorable bleb morphology.

Disclosure: One study author declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures

Reference

Dangda S, Radell JE, Mavrommatis MA, et al. Open conjunctival approach for sub-tenon’s xen gel stent placement and bleb morphology by anterior segment optical coherence tomography. J Glaucoma. 2021;30(11):988-995. doi:10.1097/IJG.0000000000001929