Deep Anterior Lamellar Keratoplasty Type 3 Bubble Management In A Case Of Monoclonal Gammopathy

To describe the management of type 3 big bubble during deep anterior lamellar keratoplasy (DALK) in a case with corneal opacities due to monoclonal gammopathy of unknown significance (MGUS).

Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom (UK)

A 67-year-old man with central opacities of the cornea secondary to monoclonal gammopathy of unknown significance (MGUS) underwent left eye DALK. The right eye had previously undergone penetrating keratoplasty (PK) and later phacoemulsification and intra-ocular lens insertion many years ago. The left eye visual acuity before surgery was 6/60 (6/36 with pinhole). After partial trephination and air injection into the deep stroma with a blunt cannula (Fontana), a mixed type 1 and type 2 bubble was formed (type 3). The management of the case was carried out with superficial keratectomy manually performed, then careful opening of the type 1 bubble with a blade, followed by careful dissection of the pre-Descemet layer plane, avoiding direct manipulation of the type 2 bubble to minimise the risk of bursting. The type 2 bubble, which extended across all of the inferior half of the cornea, was left intact, and the donor corneal button, which had the endothelium removed, was sutured to the host cornea with interrupted sutures. The type 2 bubble remained at day one post-operation, but resolved completely after one week. After three months, his left eye visual acuity improved to 6/18 (pinhole 6/12), and the graft remained clear. 

The presence of type 2 bubbles in DALK is associated with an increased rate of conversion to PK. The co-existence of a type 1 and a type 2 bubble (type 3 bubble) allows the opportunity to complete lamellar keratoplasty successfully, with careful dissection of the type 1 bubble, and only conservative management of the type 2 bubble. This approach minimises the risk of conversion to PK and also provides excellent visual outcome, as the type 2 bubble resolves spontaneously, without affecting the transparency of the graft.