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Reverse big bubble: a new technique for preparing donor tissue of Descemet membrane endothelial keratoplasty
  1. S Zarei-Ghanavati,
  2. H Khakshoor,
  3. M Zarei-Ghanavati
  1. Mashhad University of Medical Sciences, Mashhad, Iran
  1. Correspondence to Dr Siamak Zarei-Ghanavati, Department of Ophthalmology, Khatam-al-Anbia Eye Hospital, Mashhad University of Medical Sciences (MUMS) Eye Research Center, Abootaleb Boulevard, Mashhad, 91959-65919, Iran; sizagh{at}, zareis{at}

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Recently, endothelial keratoplasty has been shown to offer a promising alternative to penetrating keratoplasty for the management of corneal endothelial failure. Melles et al1 introduced a new technique for transplantation of Descemet membrane (DM) through a self-sealing incision, which they referred to as Descemet membrane endothelial keratoplasty (DMEK). They obtained donor material by stripping DM with fine forceps. This is a challenging and time-consuming procedure with inevitable endothelial cell loss and possibility of DM tear. Herein, we describe a new technique to prepare donor tissue for DMEK, the reverse big-bubble technique.

Surgical technique

A corneoscleral button was placed endothelial side up on a donor Barron punch and fixed by grasping the outer scleral edge. The endothelial layer was stained with trypan blue. A 27-gauge bevel-up needle attached to a 2 ml syringe filled with air was inserted into the posterior stroma with the entry point located just outside of the Schwalbe line. The needle was advanced to the central cornea. Air was gently injected causing corneal emphysema. The small air bubbles that formed rapidly coalesced into a big bubble detaching DM from the posterior stoma. The needle was removed from the cornea and introduced into the big bubble from the scleral part of the corneoscleral rim to collapse the bubble by aspirating the air. Finally, a Barron punch (8.5 mm in diameter) was used to punch donor the DM from endothelial side (figure 1).

Figure 1

(A) Trypan blue stained corneoscleral button on the Barron punch base. (B) Insertion of the 27-gauge needle attached to an air-filled syringe with the entry point located outside of the Schwalbe line. (C) Small bubbles formation after gentle air injection. (D) Coalesced small bubbles into a big bubble and detaching DM from the posterior stoma. (E) Reinsertion of the needle into the big bubble from the scleral part of the corneoscleral rim to collapse the bubble. (F) Punched and rolled donor DM ready to transplant.


Endothelial keratoplasty has become a popular procedure for treatment of corneal endothelial disorders. This leaves a secure eye with less postoperative astigmatism when compared with penetrating keratoplasty. In recent years, various techniques for endothelial keratoplasty have been described, namely, deep lamellar EK (DLEK), Descemet stripping (automated) endothelial keratoplasty (DSEK/DSAEK) and DMEK. Preliminary results have shown that DMEK offers a faster visual rehabilitation and better optical quality than DSAEK.2 Although donor tissue preparation for DMEK is not dependent on expensive equipment, the manual dissection is difficult and tedious for many surgeons. Use of the air injection into the cornea with the aim to separate the DM from the stroma, first described by Anwar and Teichmann3 in their big-bubble technique, can be used to harvest donor DM as well. The big bubble technique was originally described for deep anterior lamellar keratoplasty, but we have used it for preparation of donor DM. Interestingly, this reverse big bubble formation is much easier in a donor button than in the living eye of a patient during the deep anterior lamellar keratoplasty procedure.

In comparison with manual dissection of donor DM, it can be done faster, easier and without endothelial cell touch during the detachment. In addition, the technique is familiar to many surgeons and has a short learning curve. Lie JT et al4 reported 4% to 7% endothelial cell loss after stripping DM. We did not perform specular microscopy, but we suppose less endothelial loss rate would be less because it requires minimal touch and is a less traumatising procedure.

As this was an experimental study, we used trypan blue to visualise the endothelium. The procedure can be performed without trypan blue staining because this dye can be toxic to the endothelium and would not be recommended in actual surgical practice.



  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.