An approach to reduce Descemet抯 membrane scrolling: Relevance to Descemet抯 membrane endothelial keratoplasty (DMEK)

Purpose: We aimed to determine whether Descemet抯 membrane (DM) scrolling occurs primarily along the vertical or horizontal axis and establish whether oval trephination along the axis of least scrolling can reduce the grade of the scroll. Methods: The longest limbus?to?limbus axis on 28 sclerocorneal discs was taken as the horizontal axis. The horizontal (n = 7) or (right angles to it) vertical (n = 6) axis was marked on DM before peeling it off. The direction and grade of scrolling was observed. Narrow strips (3�mm wide) were then cut along the two axes (n = 4 each) and the scrolling pattern was observed. Ellipses (7 � 9 mm) of DM were punched along the two axes (n = 6 each) and the scrolls graded. Immunofluorescent staining for elastin on horizontal and vertical tissue sections from three DM samples was performed. The intensity and thickness of elastin staining were measured. Results: Twenty?four (85.72%) DM samples showed scrolling along the horizontal axis, none showed scrolling along the vertical axis, and four (14.28%) samples showed a spiral scroll, regardless of which axis was marked (grade 3.7 and 3.6). Vertically oval discs showed significantly reduced scrolling (grade 1.2) compared to horizontally oval discs (grade 3.5). Narrow strips of DM showed a similar scrolling pattern. Immunohistology showed no difference in any of the parameters examined along the two axes or from the center to the periphery. Conclusion: DM scrolls primarily along the horizontal axis. Vertically oval DM samples show minimal scrolling, which can be an advantage in DMEK. Differential scrolling is not determined by the distribution of elastin.

Indications and types of keratoplasties: Trends in the past 10 years (2011-2020) in Eastern India

Purpose: To observe the trends of various types of keratoplasties in different etiologies over a period of 10 years (2011?2020) in a tertiary eye care center of eastern India. Methods: A retrospective review of patients undergoing keratoplasties from 2011 to 2020 was performed in a tertiary eye care hospital situated in eastern part of India. Apart from demographic data, primary indication for each surgery and type of procedure carried out was recorded. For comparison, data were divided into two time periods: Group I: Jan 2011 to Dec 2015 and Group II: Jan 2016 to Dec 2020. Results: Over a period of 10 years, a total of 2365 (Group I: 902, Group II: 1463) keratoplasties were performed. The average age of patients was 45.8 � 19.9 and 46.9 � 20.9 years in Group I and Group II, respectively. Among all the corneal grafts, 1747 (74%) surgeries were full?thickness. Although optical penetrating keratoplasty (OPK) was most the common indication for full?thickness keratoplasties, Descemet抯 stripping endothelial keratoplasty (DSEK) remained most performed lamellar keratoplasty. Keratitis, corneal scars, and bullous keratopathies remain to be most common indications in both groups. Number of lamellar keratoplasties increased significantly from Group I to Group II for corneal scars (P = 0.02), bullous keratopathies (P = 0.01), and endothelial dystrophies (P = 0.00). Conclusion: With change in time, the indication and technique of keratoplasty has witnessed a changing trend from full?thickness keratoplasty to lamellar keratoplasty. There is rise in trend of lamellar keratoplasties over the period

A goat eye, wet lab model for training in Descemet membrane endothelial keratoplasty

Here we describe a new, non-human, ex-vivo model (goat eye model) for training surgeons in DMEK surgeons. In a wet lab setting, goat eyes were used to obtain a pseudo-DMEK graft of 8 mm from the goat lens capsule that was injected into another goat eye with the same maneuvers described for human DMEK. The DMEK pseudo-graft can be easily prepared, stained, loaded, injected, and unfolded into the goat eye model reproducing the similar maneuvers used for DMEK in a human eye, except for the descemetorhexis, which cannot be performed. The pseudo-DMEK graft behaves similar to human DMEK graft and useful for surgeons to experience and understand steps of DMEK early in learning curve. The concept of a non-human ex-vivo eye model is simple and reproducible and obviates the need for human tissue and the issues of poor visibility in stored corneal tissue.

Descemet membrane endothelial keratoplasty (DMEK) aquarium: Diving in to learn DMEK surgical concepts

A novel simulation model (without using human corneas) has been described for understanding the surgical concepts and developing tactile reflexes of Descemet membrane (DM) endothelium scroll manipulation and orientation in the anterior chamber, which are necessary for performing Descemet membrane endothelial keratoplasty (DMEK). Termed the “DMEK aquarium,” this model helps facilitate the understanding of different maneuvers of the DM graft needed inside the fluid-filled anterior chamber, like unrolling or unfolding, flipping or inversion, and checking orientation and centration in the host cornea. A stepwise plan for surgeons starting to learn DMEK utilizing various available resources is also suggested.

Intraoperative optical coherence tomography-guided donor corneal tissue assessment and preparation

Purpose: To evaluate the role of intraoperative optical coherence tomography (i?OCT) in donor grading, selection, and preparation during different types of keratoplasty. Methods: Seventy?one consecutive donor corneas collected over 6 months, after clinical grading, were observed by an experienced corneal surgeon under an i?OCT equipped microscope. The donor preparation (manual/automated) for different types of keratoplasty procedures was also undertaken under i?OCT. Results: The mean central corneal thickness of optical and nonoptical grade tissues was 533 ± 19 and 662 ± 52 ?m, respectively. The i?OCT?based grading matched with clinical grading in 98.5% cases. Irregular thickness, anterior stromal hyperreflectivity, and previous scars were appreciated in 1.4, 1.4, and 7.04% donors, respectively. During Descemet stripping automated endothelial keratoplasty, i?OCT facilitated selection of appropriate microkeratome head for automated donor preparation in all cases, besides allowing manual dissection of partially dissected lenticule, identification of site of inadvertent perforation, and eccentric trephination in one case each. During Descemet membrane endothelial keratoplasty, i?OCT?based assessment of preexisting scar (five cases) guided careful tissue selection (2/5) and preparation. During predescemetic endothelial keratoplasty, precise needle advancement allowed successful type?1 bubble formation in all cases. All manually punched donors demonstrated an extra endothelial ledge, while those with automated preparation showed tapering donor margins. Conclusion: i?OCT might serve as a useful imaging tool for objective assessment of donor characteristics. The modality may complement clinical evaluation for donor grading, selection, and preparation.

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

Flanged intraocular lens (IOL) implantation with scleral pockets - A modification of flanged IOL technique (E-Flanged IOL) for secondary lens implantation

During pandemic, eye banks worldwide faced drastic reduction of corneal retrieval. Since precut tissues are uncommon in India, the onus is on corneal surgeons to maximize the donor corneal usage. The stumbling block making the stromal part unusable in the graft preparation of the Descemet membrane endothelial Keratoplasty is the stromal window creation to place the orientation mark on the stromal side of the folded graft. To overcome this, we simply marked directly on the folded Descemet graft, after partly stripping it from the donor cornea. Then, we unfolded, punched, and created two grafts after completely stripping it, retaining the Descemet part for the endothelial Keratoplasty and the stromal part for lamellar Keratoplasty. Initially, we used a special F marker, and later we marked an L using just a spatula. This simple technique needing no extra donor tissue or instrumentation maximizes the tissue utility with proper patient selection.

Resource maximization during COVID-19 crunch – A novel graft marking technique to use one cornea for two recipients for either Descemet membrane endothelial keratoplasty or deep anterior lamellar keratoplasty

During pandemic, eye banks worldwide faced drastic reduction of corneal retrieval. Since precut tissues are uncommon in India, the onus is on corneal surgeons to maximize the donor corneal usage. The stumbling block making the stromal part unusable in the graft preparation of the Descemet membrane endothelial Keratoplasty is the stromal window creation to place the orientation mark on the stromal side of the folded graft. To overcome this, we simply marked directly on the folded Descemet graft, after partly stripping it from the donor cornea. Then, we unfolded, punched, and created two grafts after completely stripping it, retaining the Descemet part for the endothelial Keratoplasty and the stromal part for lamellar Keratoplasty. Initially, we used a special F marker, and later we marked an L using just a spatula. This simple technique needing no extra donor tissue or instrumentation maximizes the tissue utility with proper patient selection.

The outcome of 70/30 taco insertion through a 2.8 mm clear corneal incision in Descemet’s stripping automated endothelial keratoplasty - A retrospective analysis

Purpose: To assess the long?term outcome of graft insertion by taco technique through a 2.8?mm clear corneal incision in patients undergoing Descemet’s stripping automated endothelial keratoplasty (DSAEK). Methods: This is a retrospective interventional case series of 77 eyes of 75 patients who underwent DSAEK in a tertiary eye hospital. The DSAEK donor grafts were folded to an uneven 70/30 taco and held at a single point using Utrata forceps. All insertions were through a 2.8?mm clear corneal incision except the two aphakic patients requiring combined SFIOL implantation. All patients underwent a comprehensive eye examination preoperatively and were followed up to 6 years postoperatively. Visual outcomes, graft clarity, and complications of all and endothelial cell loss in 22 patients with available postop specular microscopy were analyzed. Results: Overall, 59 (76.6%) had clear grafts until the final follow?up. Visual acuity improved in 48 (62.3%) from an average of 1.3 to 0.8 logMAR (P = 0.0001). Vision was maintained in seven and worsened in four eyes. Grafts failed in 18 (23.3%) eyes: seven (9%) were primary failures, two post rejection, four done for failed PK did not clear, four due to worsening of preexisting glaucoma, and one noncompliant failed eventually. Average endothelial cell density reduction was 26.3% (mean preop donor 2419 to postop 1779 cells/mm2; P = 0.000). Conclusion: Our study shows good long?term clinical outcome of DSAEK using Taco technique through a 2.8?mm clear corneal incision in a tertiary hospital

Clinical Outcomes of Descemet's Membrane Endothelial Keratoplasty: A 1-Year Retrospective Study

PURPOSE: To evaluate the 1-year results of Descemet's membrane endothelial keratoplasty (DMEK) in Korea. METHODS: The medical records of 9 patients (10 eyes) with endothelial disease who underwent DMEK from January 2012 to December 2013, and were followed up for more than 12 months were reviewed retrospectively. RESULTS: In 8 eyes with successful results after surgery, best corrective visual acuity (BCVA) was significantly improved from 1.64 +/- 0.21 (log MAR, mean) to 0.35 +/- 0.22 at 1 month and was maintained at 12 months (p = 0.012, Wilcoxon signed ranks test). BCVA at postoperative 3, 6 and 12 months were gradually increased (0.25 +/- 0.23, 0.20 +/- 0.17 and 0.16 +/- 0.17 log MAR). Endothelial cell counts were 1,996 +/- 528/mm2, 1,564 +/- 174/mm2 and 1,463 +/- 541/mm2, 1,205 +/- 358/mm2 at 1, 3, 6, and 12 months after surgery, tended to decrease but showed no statistical significance. There was no statistical difference in astigmatism before and 3 months after the operation (3.32 +/- 2.36 diopter and 2.57+/- 1.44 diopter). Primary graft failure occurred in 2 eyes and 1 received reoperation. Total detachment was found in 1 eye. CONCLUSIONS: The 1-year results of DMEK showed fast visual recovery which was maintained for 12 months. DMEK may be a very efficient option for the surgical management of corneal endothelial disease.

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.