Quadruple Layer Technique of Corneal Graft, Amniotic Membrane, and Conjunctiva to Prevent Recurrent Tube Erosion Following Implantation of Glaucoma Drainage Device

Background

Glaucoma drainage devices (GDDs) are an effective treatment option in patients with refractory, secondary, or advanced glaucoma [1]. GDDs consist of a tube that allows aqueous humour to flow from the anterior chamber into a post-equatorial subconjunctival base plate [1]. However, a severe complication associated with GDDs is tube erosion which may lead to hypotony and endophthalmitis [1]. Post-GDD tube erosion is believed to result from a combination of inflammatory, mechanical, and ischemic factors triggered by the foreign body presence of the tube and the associated surgical trauma [2], [3].

To mitigate the risk of tube erosion, the tube may be covered with a patch of biocompatible material, such as donor sclera, pericardium, cornea, or fascia lata [4]. The incidence of post-GDD tube erosions ranges from 0 – 12% in previous studies [3], [4]. To date, ongoing research aims to find a consensus on which patch material might be superior in terms of longevity, safety, and biocompatibility.

Revision surgeries for eroded tubes typically involve replacing the donor patch and covering it with conjunctiva. However, in patients with multiple previous ocular surgeries, conjunctival closure can be difficult to achieve due to conjunctival fragility and its firm adherence to the underlying scar tissue [5]. GDDs might have to be explanted despite good IOP lowering effects due to recurrent erosions and associated risks. Thus, there is an unmet need to address recurrent erosions in these patients avoiding tube explanting.

Amniotic membrane (AM), the innermost layer of the placenta, consists of a single epithelial layer, a thick basement membrane, and an avascular stromal matrix [6]. AM contains growth factors and anti-inflammatory cytokines, which promotes epithelialization, reduces fibrosis, and modulates the immune response [7]. Additionally, its high tensile strength, biocompatibility, and ability to integrate into host tissues make AM a suitable option for patching of tubes in GDD surgery [7]. Previous studies have shown that AM patches can improve surgical outcomes of GDD surgeries, especially in eyes with compromised conjunctiva [8]. We present, for the first time, a quadruple layer technique involving the use of a corneal graft, a double layer of amniotic membrane (AM), and conjunctiva to patch the tube of a Paul glaucoma drainage device (GDD) in a patient with recurrent tube erosions.

Publication History

Received: 08 December 2024

Accepted: 26 June 2025

Article published online:
01 September 2025

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