“PI-less DMEK”: results of Descemet’s membrane endothelial keratoplasty (DMEK) without a peripheral iridotomy

Abstract

Purpose: To assess Descemet's membrane endothelial keratoplasty (DMEK) without performing a peripheral iridotomy (PI) prior to or during surgery ("PI-less DMEK"). Materials and methods: This retrospective study included consecutive patients that underwent PI-less DMEK by a single surgeon (E.L) between February 2016 and February 2017 at the Rabin Medical Center, a Tertiary Hospital. Intraoperative and postoperative complications were assessed.Results: Thirty-one patients, mean age 75.9 ± 7.9 years with 58.1% female were included. Leading indications for surgery were pseudophakic bullous keratopathy (18/31) and Fuchs' endothelial dystrophy (9/31). Preoperative best-corrected distance visual acuity was 1.13 ± 0.59 logMAR (~6/80 Snellen). For 12/31 that had postoperative endothelial cell count measurements, cell loss was 49 ± 20%. Intraoperative complications included anterior chamber (AC) hyphema during graft insertion requiring reinsertion (n = 1), and minor hyphema from the main corneal incision (n = 1). Partial slit lamp gas evacuation was performed in all patients 1.5 h postoperatively. Postoperative complications included partial graft detachment requiring rebubbling (n = 5), self-resolving minimal peripheral graft detachment (n = 5), uncontrolled intraocular hypertension requiring trabeculectomy in a patient with a history of medically controlled glaucoma (n = 1), postoperative cystoid macular edema that resolved medically (n = 1) and graft failure 5 months postoperatively (n = 1). No patients developed pupillary block. Excluding graft failure (n = 1), preoperative amblyopia (n = 2) and premature loss to follow-up (n = 1), final corrected distance visual acuity was 0.18 ± 0.14 logMAR (~20/30 Snellen) with 44.4% reaching 6/7.5 (Snellen) or more. Conclusions: PI-Less DMEK is a safe, technically easy, and effective modification that avoids the time and complications associated with performing a PI before or during surgery.

Real‐time intraoperative ultrasound biomicroscopy for determining graft orientation during Descemet's membrane endothelial keratoplasty

“…In both scenarios, surgeons are expected to encounter difficulties during all steps of the surgery, including identification of graft orientation and graft unfolding status ‐ which are crucial steps in this surgery. Moreover, even an experienced DMEK surgeon in a straightforward case might get disorientated with graft status when the anterior chamber inadvertently fills with pigment, blood or in cases that the blue tint of the graft fades faster than usual (Zeidenweber et al 2017; Crews et al 2018; Livny et al, 2019a, 2019b).…”

“…Then, a hand‐held UBM immersion probe (40 MHz UBM Wide‐Field Anterior Segment probe, Eyecubed, Ellex Medical Lasers, SA Australia – Cases 1–5 and 50 MHz Compact touch STS UBM Probe, Quantel Medical, Cournon d'Auvergne, France – Cases 6–7) filled with ‘water for injection’ solution and covered with a sterile cover and sleeve was put onto the recipient's cornea by the surgeon or by an assistant. After ascertaining graft orientation, the rest of the surgery was done as per our standard technique (Dapena et al 2011; Livny et al, 2019a, 2019b).…”

“…The partially prestripped graft was then preserved in Eusol C (Alchimia Srl, Italy) cold storage preservation solution until surgery, which took place 1–3 days following prestripping. Further graft preparation, staining with trypan blue (Vision Blue, DORC, Netherlands) and intracameral implantation were done in a standardized ‘no‐touch technique’ as previously described, with the modification of avoiding peripheral iridectomy, as described by our group (Dapena et al 2011; Livny et al, 2019a, 2019b).…”

“…These include techniques which involve touching or altering the graft like the ‘blue cannula tip’ sign (‘Moutsouris sign’), marking the Descemet's side of the graft with an ‘F’ or ‘S’ using a gentian violet skin marker through a stromal window (Parekh et al 2017), Punching orientation marks (Kruse et al 2011) and recently, a ring‐shaped peripheral staining of graft using gentian violet proposed by our group (Livny et al, 2019a, 2019b).…”

Rebubbling of detached descemet membrane endothelial grafts at the slit lamp with 50% air fill after PI-less DMEK during COVID-19 era

“…2 However, performing DMEK without a PI has also been described and has been shown to be a safe and effective modification. 3 One of the potential complications of DMEK surgery is early graft detachment, requiring re-injection of air or gas into anterior chamber to reposition the graft. 4,5 As this requires relatively little manipulation, such rebubbling can be performed at the slit lamp instead of the operating theatre.…”