DMEK FOR A PATIENT WITH APHAKIA AND ANIRIDIA AFTER 2 FAILED DSAEK IN AN ONLY EYE

To share practical tips to facilitate a successful DMEK in patients with aphakia and aniridia.

IRIS Ophthalmology Centre, Nicosia, Cyprus

We report a case of a 38-year-old male patient who successfully underwent Descemet’s Membrane Endothelial Keratoplasty (DMEK) in an aphakic and aniridic eye. His ophthalmic history includes right eye cataract surgery, pathological myopia, vitrectomy for macula-off retinal detachment, and 2 Descemet's Stripping Automated Endothelial Keratoplasties (DSAEK). He presented to our clinic with a failing DSAEK graft, with a visual acuity of 6/120 one year following surgery. His left eye has no perception of light since early childhood. Typically, the choice of DSAEK over DMEK in aphakic or aniridic eyes is due to the ability to secure the graft with sutures, which reduces the risk of dislocation into the vitreous. However, DMEK is associated with significantly lower rejection rates, an important consideration for our patient who experienced 2 prior graft failures. Furthermore, post-operative detachments in DSAEK are usually total, whereas in DMEK, detachments are more often partial and can be repaired by re-bubbling. In order to exploit the advantages of DMEK, we utilised the 'safety-net' technique described by Berger et al. (Cornea, 2022). This involves creating a pseudo-anterior chamber using a 10.0 polypropylene suture in a 3x5 cat's cradle configuration. It is crucial to place the suture prior to the first incision to avoid collapse of the eye when passing the needle. The suture should be made purposely tight because it will loosen when the eye is opened during surgery. Furthermore, it is important to choose a DMEK graft with a high endothelial count of an older non-diabetic donor, which is not pre-peeled, to facilitate unfolding of the graft and minimise risk of detachment. Also, 10.0 nylon sutures should be pre-placed on the main incision to allow quick stabilisation of the pseudo-anterior chamber following graft injection. During the injection step, the donor graft should be positioned in the correct orientation, at the tip of the Gauder cannula. The cannula should then be inserted fully in the anterior chamber to minimise risk of graft rotation. Moreover, we advise that SF6 instead of air is used to attach the graft. The cat’s cradle suture was left in place at the end of surgery and removed once graft attachment was confirmed the following day. To minimise manipulation of the suture, it is cut in various places and then pulled through. At 4 months post-operative assessment the patient’s visual acuity improved to baseline (6/24) .

Successful application of the ‘safety-net’ technique adds real-world data for DMEK’s feasibility in aphakia and/or aniridia. This case promotes broader adoption of the technique offering a viable alternative for patients in similar complex clinical scenarios with limited surgical options.