Microtrauma-induced recurrent hyphema and secondary glaucoma associated with chronic acetylsalicylic acid use

Seventy-one cases of uveitis-glaucoma-hyphaema syndrome

PURPOSE

To assess Uveitis-Glaucoma-Hyphaema syndrome (UGH syndrome) with focus on resolution, glaucoma development and risk factors.

METHODS

This retrospective case-control study with a cross-sectional component was performed to compare three groups with 71 patients each: UGH syndrome, dislocated intraocular lens (IOL) without UGH syndrome and ordinary pseudophakia. Main outcome measures were resolution of the UGH syndrome, best-corrected visual acuity (BCVA) and the need of glaucoma therapy. We also assessed the IOL-iris contact signs and the use of blood thinners.

RESULTS

Uveitis-Glaucoma-Hyphaema (UGH) syndrome resolved in 77 % of patients who underwent various kind of IOL surgery. Intraocular pressure (IOP) decreased and BCVA improved in the operated cases (p = 0.02 and p < 0.001, respectively), but not in the cases treated conservatively. Intraocular pressure (IOP) ≥22 mmHg at the first haemorrhage predicted the need of glaucoma therapy after UGH syndrome resolution (p = 0.002, area under the curve = 0.8). Fifty-one per cent of patients without preexisting glaucoma needed glaucoma therapy after UGH syndrome resolution. Pseudophacodonesis was seen more frequently in the UGH group than in the ordinary pseudophakia group (p = 0.001). Iris defects were not more frequent in the UGH group than in the Dislocated group but the types of defects differed (p < 0.0001). Blood thinners were not more frequent in UGH.

CONCLUSION

In UGH syndrome, the results are better with surgical intervention than with conservative treatment, but surgery does not guarantee resolution. Pseudophacodonesis is a risk factor for UGH syndrome, but blood thinners are not, and iris defects are not specific to UGH syndrome. A high IOP at the first haemorrhage increases the risk for needing subsequent IOP-lowering therapy.

Delayed Obstruction of XEN Gel Stent by Cell Debris in Primary Open-angle Glaucoma: A New Insight into the Pathophysiology of Filtration Device Failure

Aim

The aim of this report is to explore the risk factors of XEN stent obstruction, suggesting the need for a stricter control of these factors and highlighting areas for further research.

Background

Despite its proven effectiveness and safety profile, XEN gel stents (Allergan Plc, Dublin, Ireland) can become obstructed. The causes and predicting factors for such obstructions still require further research. While hyphema has long been known to be responsible for secondary glaucoma through trabecular obstruction, it has not been associated, to date, with XEN gel stent obstruction.

Case description

We describe the case of a 55-year-old female patient with primary open-angle glaucoma (POAG) who underwent bilateral XEN gel surgery. Her left eye developed a 2 mm postoperative hyphema, which resolved spontaneously within 8 days. Intraocular pressure (IOP) normalized at 12 mm Hg and increased to 50 mm Hg after 1 month in an otherwise normal-looking eye. Intraoperative examination revealed a nonfunctioning XEN gel stent, which was replaced and sent for laboratory analysis. Macroscopic examination of the tube confirmed obstruction with cellular debris. Tube replacement restored good filtration.

Conclusion

This case report confirms cellular debris as a potential cause of XEN gel stent occlusion, suggesting that aqueous red blood cells (RBCs) could potentially pose a threat to the microstents’ patency even in cases when the bleeding was minimal and self-limited and where the IOP was still controlled at the time of full hyphema resolution. This observation could lead to recommendations for a stricter control of bleeding risk factors prior to microinvasive glaucoma surgery (MIGS), and it raises the question of whether anterior chamber (AC) washout should be advised in postoperative hyphema.

Clinical significance

This case highlights some previously unreported risk factors for XEN stent obstruction and suggests that stricter control of bleeding and monitoring of patients following hyphema could improve surgical outcome.

How to cite this article

Gillmann K, Bravetti GE, Mansouri K. Delayed Obstruction of XEN Gel Stent by Cell Debris in Primary Open-angle Glaucoma: A New Insight into the Pathophysiology of Filtration Device Failure. J Curr Glaucoma Pract 2019;13(3):113–115.