Preferred practice pattern for Descemet membrane endothelial keratoplasty surgeries: A survey of Indian corneal surgeons

Purpose: This study aims to assess the preferred surgical technique of Descemet membrane endothelial keratoplasty (DMEK) among corneal surgeons in India, and barriers in performing DMEK surgeries amongst the non?DMEK surgeons. Methods: An online, questionnaire-based, cross-sectional survey was conducted among members of the Cornea Society of India (CSI) (n = 500). Responses on their surgical experience, preferred technique, complications, and outcome of DMEK were collected and analyzed. Barriers in performing DMEK surgeries were assessed amongst the non?DMEK surgeons. Results: A total of 100 responses were obtained and response rate for the survey was 20%. DMEK was performed by 55% of the participants of whom only 40% had formal training in this technique. Surgical video-based learning was the most often used self-training method for others. Lack of training was the most common reason for not performing DMEK by the non-DMEK surgeons. Descemet stripping endothelial keratoplasty (DSEK) was the most common endothelial keratoplasty (EK) performed by both DMEK and non-DMEK surgeons. High volume (>50 cases) DMEK surgeries were reported by limited surgeons (n = 6). Nearly all the DMEK surgeons prepared the donor tissue by themselves on the day of the surgery, and majority felt that unrolling the graft in the anterior chamber was the most difficult surgical step. Nearly 80% of the DMEK surgeons were more comfortable with DSEK or Descemet stripping automated endothelial keratoplasty (DSAEK) when compared to DMEK. Conclusion: DMEK practice in India needs improvement with increased accessibility to DMEK training programs, wet lab facilities, and better support from eye banks

Causes and treatment of complications in different stages of endothelial keratoplasty / 中华实验眼科杂志

As an ideal surgical method for treating corneal endothelial decompensation, endothelial keratoplasty has been widely applied.It has many advantages, but there are also complications during graft preparation, intraoperative operation and postoperative recovery.The two common types of corneal endothelial keratoplasty, Descemet-stripping automated endothelial keratoplasty and Descemet membrane endothelial keratoplasty, were taken as examples in this article to introduce the treatment of complications during graft preparation, such as graft perforation and graft tear, intraoperative complications, for instance, difficulty in expanding graft and graft inversion, postoperative complications including graft detachment, high intraocular pressure, etc.The incidence of complications at different stages of endothelial keratoplasty, influencing factors and treatment methods were reviewed to provide a reference for clinicians to diagnose and treat complications of endothelial keratoplasty at various stages.

A Case of Herpes Simplex Keratitis after Descemet Membrane Endothelial Keratoplasty

PURPOSE: We report a case of herpes simplex keratitis after Descemet membrane endothelial keratoplasty (DMEK). CASE SUMMARY: A 67-year-old male underwent DMEK in his left eye due to pseudophakic bullous keratopathy. One week after DMEK, re-bubbling was performed due to partial detachment of Descemet's membrane at the corneal periphery. After re-bubbling, the cornea remained clear and the patient's visual acuity gradually improved. Two months after DMEK, the patient presented with mild discomfort and decreased visual acuity. The cornea showed an irregular, narrow dendrite with an epithelial defect and surrounding opacity. After confirming that Descemet's membrane was attached, the patient was started on oral valacyclovir for suspected herpes keratitis. Herpes simplex virus type 1 was eventually identified by polymerase chain reaction. The corneal lesion resolved after three weeks of antiviral treatment. CONCLUSIONS: Similar to penetrating keratoplasty, DMEK can trigger outbreaks of herpes simplex keratitis. Herpes simplex keratitis should remain on the clinician's differential diagnosis for patients who present with a corneal epithelial irregularity and decreased visual acuity following DMEK.

Lamellar keratoplasty techniques

Lamellar keratoplasty (LK) has revolutionized corneal graft surgery in several ways. Deep anterior LK (DALK) has eliminated risk of failure due to endothelial rejection. Endothelial keratoplasty (EK) has almost eliminated induced astigmatism and the “weak” graft–host junction as seen with penetrating keratoplasty (PK) and also reduced the risk of endothelial rejection. LK provided new insights into posterior corneal anatomy that led to better understanding and performance of DALK and to the development of another EK procedure, namely pre-Descemet's EK (PDEK). Surgical procedures for LK were further refined based on the improved understanding and are able to deliver better surgical outcomes in terms of structural integrity and long-term patient satisfaction, reducing the need of further surgeries and minimizing patient discomfort. In most specialist centers, anterior lamellar techniques like DALK and EK techniques like Descemet's stripping EK (DSEK) and Descemet's membrane EK (DMEK) have replaced the full-thickness PK where possible. The introduction of microkeratome, femtosecond laser, and PDEK clamp have made LK techniques easier and more predictable and have led to the innovation of another LK procedure, namely Bowman membrane transplant (BMT). In this article, we discuss the evolution of different surgical techniques, their principles, main outcomes, and limitations. To date, experience with BMT is limited, but DALK has become the gold standard for anterior LK. The EK procedures too have undergone a rapid transition from DSEK to DMEK and PDEK emerging as a viable option. Ultrathin-DSEK may still have a role in modern EK.

Disección neumática en dos pasos para la preparación del tejido donante en queratoplastia endotelial de la membrana de Descemet / Two-step pneumatic dissection in the preparation of donor tissue for Descemet membrane endothelial keratoplasty

Objetivos: evaluar los resultados de una variante técnica para la preparación del tejido donante en la queratoplastia endotelial de la membrana de Descemet. Métodos: se realizó un estudio experimental exploratorio en 20 córneas donantes humanas no útiles para trasplante corneal en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer". La variante técnica consistió en la disección neumática en dos pasos y abordaje posterior hasta conseguir la total separación de la membrana de Descemet. Se midió el tiempo quirúrgico, el diámetro del desprendimiento y la aparición de complicaciones. Se realizó estudio histológico de córneas con resultados biomicroscópicos atípicos. Resultados: se obtuvo el 95 % de tejido útil para trasplante en base a la integridad del tejido. El tiempo quirúrgico medio fue de 8,5 minutos y el diámetro medio de la bula de 9,3 mm. Ocurrió ruptura de la membrana de Descemet en dos casos. En tres discos se formaron dobles bulas, una parcial y dos completas. El estudio histológico mostró que la bula interna estaba compuesta por capa aislada de estroma posterior y la externa por membrana de Descemet y endotelio. Conclusiones: la variante técnica resultó reproducible y segura en la preparación del tejido donante. Las características ultraestructurales del estroma posterior permiten la disección de una capa independiente lisa, resistente y transparente. En algunos especímenes se observó la disección no solo de la membrana de Descemet y endotelio, sino que se presenciaron remanentes de capa de estroma posterior en las bulas simples.

Objective: to evaluate an alternative of double pneumatic dissection in the preparation of donor tissue for Descemet Membrane endothelial keratoplasty. Methods: experimental exploratory study of 20 human donor corneas that were useless for corneal transplant was performed in the "Ramón Pando Ferrer" Cuban Institute of Ophthalmology. The technical variant was two-step pneumatic dissection and posterior approach in order to completely detach Descemet membrane. The mean surgical time, the size of the detachment, the arisen complications and histologic examination in cases of atypical biomicroscopic findings were evaluated. Results: ninety five percent of useful tissue for transplant was obtained. The mean surgical time was 8.5 min and the mean size of bubble was 9.3 mm. Rupture of Descemet membrane occurred in two cases. Three discs presented formation of double bubbles, one partial or two complete ones. The histological study showed that the innermost bubble was made up of an isolated layer of posterior stroma and the outer bubble made up of Descemet membrane and endothelial cells. Conclusions: this technical variant proved to be reproducible and safe for donor tissue preparation. The ultra-structural characteristics of the posterior deep stroma allow the dissection of an independent layer which is thin, smooth, resistant and transparent. In some specimens, the dissected tissue included not only Descemet membrane and endothelium, but also remnants of the posterior stroma layer in simple bubbles.

Descemet membrane endothelial keratoplasty with a stromal rim in the treatment of posterior polymorphous corneal dystrophy.

A 20-year-old patient, diagnosed with posterior polymorphous corneal dystrophy, developed corneal edema for which he underwent Descemet membrane endothelial keratoplasty with a stromal rim (DMEK-S) in the right eye. No intra- or postoperative complications were noted. At the last follow-up 2 years and 9 months after the procedure, the best corrected visual acuity was 1.0 and endothelial cell density declined from 3533 cells/mm2 to 1012 cells/mm2. Despite the endothelial cell loss, DMEK-S appears to be a good alternative to other surgical techniques for the treatment of corneal endotheliopathies, and it may be of benefit to young patients.