Double-Bubble Technique in Descemet Membrane Endothelial Keratoplasty for Vitrectomized Eyes: A Case Series

Descemet Membrane Endothelial Keratoplasty in Aphakic, Aniridic, and Vitrectomized Eyes: A Review

PURPOSE

The aim of this review is to examine the techniques, complications, and outcomes of Descemet membrane endothelial keratoplasty (DMEK) in aphakic, aniridic, and vitrectomized eyes.

METHODS

A literature search was conducted in the MEDLINE database (via PubMed), using as keywords "(DMEK) AND (aphakia OR aniridia OR vitrectomy OR vitrectomized)." The research was limited to 10 years (January 2014-March 2024), in view of lack of literature before 2014. Articles, including case reports and case series, were included.

RESULTS

Twenty articles were included. No randomized controlled trials were found nor comparative studies with more than 1 technique used. Mean rebubbling rate in complex eyes was 29%, whereas mean endothelial cell loss at 6 months was 37%. The mean postoperative visual acuity improved from 1.47 logarithm of the minimal angle of resolution to 0.7 logarithm of the minimal angle of resolution.

CONCLUSIONS

Despite being more challenging, compared with the techniques reported in literature, DMEK can be considered a valid option for the management of endothelial decompensation in complex eyes, with rebubbling rate and endothelial cell loss at 6 months, which are similar to non-complex eyes.

Double-Bubble Technique Assisted by Holding Forceps: A Modified Technique in Descemet Membrane Endothelial Keratoplasty for Vitrectomized Eyes With Scleral Fixated Intraocular Lens

PURPOSE

Several techniques have been developed for graft unfolding approaches in Descemet membrane endothelial keratoplasty (DMEK). However, despite these techniques, graft deployment and configuration in eyes with deep anterior chambers remain challenging in some cases. Therefore, in this study, we described a modified technique for DMEK, known as the "double-bubble technique assisted by holding forceps."

METHODS

This was a retrospective interventional case series. Patients who underwent DMEK between August 2022 and July 2023, including cases with a history of vitrectomy and scleral fixation of intraocular lens, were enrolled in this study. Two experienced surgeons performed DMEK. In brief, after graft insertion into the anterior chamber, the first bubble with a small volume of air was injected above the graft to open the tight roll, and the graft edge was held using a 25-gauge graft manipulator. The second bubble was injected underneath the graft for fixation, while the graft edge was grasped using forceps during gas injection. The graft was released from the forceps. Best spectacle corrected visual acuity, central corneal thickness, endothelial cell density, and incidence of postoperative complications were measured before and after DMEK.

RESULTS

Eleven eyes of 11 patients were included in this study (mean follow-up period, 4.5 ± 4.4 months). Best spectacle corrected visual acuity and central corneal thickness significantly improved postoperatively ( P < 0.001). Rebubbling was required in 2 eyes; no other postoperative complications or primary graft failure were observed.

CONCLUSIONS

The present technique enables safe and feasible DMEK surgery in vitrectomized eyes with scleral fixated IOLs and in those with a deep anterior chamber.

Novel technique to improves graft unfolding in vitrectomized eyes during Descemet membrane endothelial keratoplasty

INTRODUCTION

Descemet membrane endothelial keratoplasty (DMEK) is commonly used to treat endothelial pathologies in bicameral pseudophakic eyes with a normal depth of the anterior chamber. However, performing this procedure on eyes that have undergone vitrectomy carries a higher risk of complications. Therefore, this report presents a novel technique for improving the unfolding of a DMEK graft in a vitrectomized eye.

PRESENTATION OF CASE

A 49-year-old man with a history of complicated cataract surgery one year prior was referred to our clinic with pseudophakic bullous keratopathy in his left eye. The surgery involved a posterior capsular rupture, anterior vitrectomy, and implantation of a sulcus three-piece intraocular lens. DMEK and anterior vitrectomy were performed. However, the conventional tap technique was unsuccessful in unfolding the DMEK graft, owing to intraoperative hypotony and an inability to flatten the anterior chamber.

DISCUSSION

To minimize excessive manipulation of the donor tissue, a 27-gauge cannula attached to a 3-cc syringe was used. A cannula was introduced through paracentesis near the edge of an unfolded DMEK graft. We then created a suction force by pulling back the plunger while slowly moving the needle backward during the graft unfolding. The postoperative course was uneventful, with a clear and fully attached DMEK graft.

CONCLUSIONS

This technique reduces the complexity of DMEK graft unfolding in vitrectomized eyes, enabling easier and more controlled unfolding. However, further research with larger patient populations is required to determine the clinical relevance of this method.

Descemet Membrane Endothelial Keratoplasty with cornea press technique and implantation of a Carlevale scleral-fixated intraocular lens

Purpose

We describe a combined Descemet Membrane Endothelial Keratoplasty (DMEK) using the Cornea-press (C-Press) technique, with implantation of a new sutureless, scleral fixated intraocular lens (IOL) (Carlevale, Soleko), in a case of bullous keratopathy and IOL mispositioning.

Observations

Two scleral pockets were created along two scleral radial incisions, 180° apart, followed by two 23 G sclerotomies at the pockets' sites. After removal of the dislocated IOL through a corneoscleral incision, posterior vitrectomy was completed. The Carlevale IOL was injected into the anterior chamber (AC) and placed above the iris. The haptics were then externalized using opening distal forceps through the sclerotomies, and the plugs were secured in the scleral pockets. DMEK was then performed using the "C-press" technique, where corneal indentation allowed to artificially shallow the AC to ensure successful graft unrolling. Fifteen months postoperatively, the cornea was clear, the Carlevale IOL well positioned, and the patient's vision improved.

Conclusions and importance

DMEK using the C-Press technique, combined with a sutureless, scleral-fixated IOL such as the Carlevale in a single procedure, may be a safe and effective option to restore vision in case of bullous keratopathy and dislocated IOL.

A Comparison of the Corneal Thickness Following Descemet's Stripping Automated Endothelial Keratoplasty and Descemet's Membrane Endothelial Keratoplasty

PURPOSE

To compare the central corneal thickness before and after Descemet's stripping automated endothelial keratoplasty (DSAEK) and Descemet's membrane endothelial keratoplasty (DMEK), and to evaluate the recipient corneal thickness following DSAEK.

METHODS

The corneal thickness was compared between two groups of eyes following DMEK and DSAEK, performed by a single surgeon between 2015 and 2017. We evaluated the recipient corneal thickness and central corneal thickness pre- and postoperatively at 1, 3, and 6 months using anterior segment optical coherence tomography. Recipient corneal thickness was defined as the corneal thickness without graft thickness.

RESULTS

We included DMEK and DSAEK eyes (n = 26 each), which were similar in terms of their etiologies. Preoperatively, there was no significant difference in the central corneal thickness between the groups (DSAEK, median [interquartile range]: 721 [606.5 to 847.8] µm; and DMEK: 690 [618 to 722.3] µm; p = 0.30). Despite the tendency of the central corneal thickness to be significantly greater (p < .01) at 6 months following DSAEK (619.5 [607.8 to 661.3] µm) compared with that following DMEK (497.5 [475.8 to 525.3] µm), there was no significant difference at 6 months between the recipient corneal thickness following DSAEK (488.5 [443.8 to 515] µm) and central corneal thickness following DMEK (p = 0.54).

CONCLUSIONS

DSAEK eyes display a similar tendency of stromal thinning as DMEK eyes.

Risk factors for intraocular pressure elevation following Descemet membrane endothelial keratoplasty in Asian patients

PURPOSE

To investigate risk factors for increased intraocular pressure (IOP) after Descemet membrane endothelial keratoplasty (DMEK) in Asian patients.

METHODS

Data from January 2015 to February 2021 were obtained from our prospective database. IOP elevation after DMEK was defined as IOP ≥ 22 mmHg or an increase in IOP of ≥ 10 mmHg from baseline. In addition, we examined maximum IOP. Using iCare, we measured IOP 1, 2, 3, and 6 months after DMEK, and every 6 months thereafter. Logistic regression and linear regression were performed to find factors predictive of IOP elevation and maximum IOP, respectively, based on the results of univariate analysis.

RESULTS

We enrolled 90 eyes (mean patient age, 74.9 ± 7.5 years; mean follow-up duration, 25.6 ± 9.9 months) that underwent DMEK. IOP elevation was present in 19 eyes (21%). IOP increased from 12.6 ± 3.9 mmHg preoperatively to a postoperative maximum of 17.0 ± 5.5 mmHg up to 36 months after DMEK (p < 0.0001). In univariate logistic regression analysis for IOP elevation, only one variable, pseudoexfoliation syndrome (PEX) and preexisting glaucoma, was significant (p < 0.05). Preexisting glaucoma without PEX (OR, 19.33; 95% CI, 4.75-93.46), PEX without glaucoma (OR, 7.25; 95% CI, 1.20-41.63), and PEX glaucoma (OR, 58.00; 95% CI, 6.78-1298.29) were associated with higher risk of IOP elevation.

CONCLUSIONS

In this cohort, the eyes of patients with PEX and preexisting glaucoma were found to be prone to IOP elevation after DMEK.

Posterior Segment Air Injection-Assisted Descemet Membrane Endothelial Keratoplasty in Pseudophakic and Vitrectomized Eyes

PURPOSE

This study aimed to present a novel technique for Descemet membrane endothelial keratoplasty (DMEK) in pseudophakic and vitrectomized eyes.

METHODS

The sterile air was injected into the posterior eye segment (anterior vitreous cavity) as a barrier to prevent the fluid of the vitreous cavity flowing into the anterior chamber, levitating the iris-lens diaphragm to flatten the anterior chamber during the surgery. This approach assists in the unfolding of the donor endothelial graft, helping to perform DMEK surgery on patients with a posterior intraocular lens (IOL) and vitrectomy.

RESULTS

Four cases presented with corneal endothelial decompensation (pseudophakic bullous keratopathy) with previous IOL implantation and vitrectomy underwent DMEK with this technique. The Descemet endothelial graft unfolding time after air injection was 68.75 ± 8.96 seconds. No graft displacement occurred during the surgery. The uncorrected and corrected distance visual acuities were improved in 3 of 4 patients. The corneas were transparent, and there was no graft detachment observed postoperatively in all 4 patients.

CONCLUSIONS

The posterior eye segment air injection can reduce the difficulty of unfolding the DMEK graft in patients after IOL implantation and vitrectomy and the potential intraoperative and postoperative complications, allowing for easy performance of DMEK surgery on pseudophakic and vitrectomized eyes for corneal endothelial dysfunction.

The Descemet Membrane Endothelial Keratoplasty (DMEK) "Wave Maneuver"

A novel technique for Descemet membrane endothelial keratoplasty (DMEK) graft handling and centration without the endothelium touching the posterior part of the anterior chamber (AC), is presented here. It is particularly suitable for vitrectomized eyes, deep AC, and AC intraocular lenses (ACIOLs), potentially reducing surgery time and endothelial cell loss during surgery. This retrospective interventional case series includes 27 eyes with complex ocular pathology. All utilized a “Wave maneuver” to center an early elevated graft without completing graft centration on the bottom of the AC. Successful graft attachment and centration were evaluated intra and post-operatively. Best-corrected visual acuity (BCVA), central corneal thickness (CCT), and donor endothelial cell density (ECD) were measured pre-operatively, and three and six months post-operatively. DMEK grafts were successfully attached and centered in all cases. No maneuver-related complications were observed intraoperatively. BCVA improved from a pre-operative 0.2 ± 0.63, to 0.43 ± 0.49 and 0.76 ± 0.51 at the three- and six-month follow-ups, respectively (p < 0.01). CCT decreased from a pre-operative 742 ± 118, to 546 ± 87 and 512 ± 67 at three and six months, respectively (p < 0.01). ECD decreased from 2878 ± 419 cells/mm2 to 1153 ± 466 cells/mm2 at three and six months, respectively (p < 0.01). The “Wave maneuver” may be very beneficial in DMEK cases where the AC is either very deep or the bottom of the AC is compromised. The “Wave maneuver” learning curve was brief.

Descemet membrane endothelial keratoplasty in complex eyes

PURPOSE OF REVIEW

To review the current literature on Descemet membrane endothelial keratoplasty (DMEK) in complex eyes.

RECENT FINDINGS

DMEK surgery has become a standardized procedure in Fuchs endothelial dystrophy and simple bullous keratopathy. But eyes with more complex disease present unique intraoperative and postoperative challenges to the DMEK surgeon. Poor visualization during surgery, complex anterior segment anatomy, altered anterior chamber dynamics, glaucoma shunts, and congenital or iatrogenic missing or altered iris and lens make DMEK surgery extremely difficult to accomplish.

SUMMARY

DMEK is feasible in complex eyes, including advanced bullous keratopathy, eyes with history of glaucoma or vitreoretinal surgery, previous penetrating keratoplasty, uveitis, pediatric, and congenital anterior segment disorders. The tools and methods reported in the literature to accomplish DMEK in complex eyes vary widely with no particular consensus or standardization of techniques. The outcomes noted for some of these conditions demonstrate the difficulty of the surgery and the uncertainty of long-term graft survival in complex eyes. Both surgical standardization and randomized prospective data will better help elucidate DMEK's role in the corneal rehabilitation of complex eyes.

Evaluation of corneal nerves and dendritic cells by in vivo confocal microscopy after Descemet's membrane keratoplasty for bullous keratopathy

This study evaluated changes in corneal nerves and the number of dendritic cells (DCs) in corneal basal epithelium following Descemet membrane endothelial keratoplasty (DMEK) surgery for bullous keratopathy (BK). Twenty-three eyes from 16 consecutive patients that underwent DMEK for BK were included. Eyes of age-matched patients that underwent pre-cataract surgery (12 eyes) were used as controls. In vivo confocal microscopy was performed pre- and postoperatively at 6, 12, and 24 months. Corneal nerve length, corneal nerve trunks, number of branches, and the number of DCs were determined. The total corneal nerve length of 1634.7 ± 1389.1 μm/mm² before surgery was significantly increased in a time-dependent manner to 4485.8 ± 1403.7 μm/mm², 6949.5 ± 1477.1 μm/mm², and 9389.2 ± 2302.2 μm/mm² at 6, 12, and 24 months after DMEK surgery, respectively. The DC density in BK cornea pre- and postoperatively at 6 months was significantly higher than in the controls, and decreased postoperatively at 12 and 24 months and was significantly lower than that at 6 months postoperatively. Thus, our results suggest that DMEK can repair and normalize the corneal environment.

Effective Cannula Vacuuming Maneuver to Unfold the Descemet Membrane Graft

OBJECTIVES

To present the cannula vacuuming maneuver (CVM) in the Descemet membrane endothelial keratoplasty (DMEK) and to investigate the efficacy of CVM in reducing the unfolding time (UT) of the graft in cases with an unstable anterior chamber (AC).

SUBJECTS/METHODS

Forty-four eyes of 44 patients, who underwent DMEK at the ophthalmology clinic of a training and research hospital, were included in this retrospective study. Surgical videos and patient charts were examined retrospectively. In 21 cases, only no-touch technique maneuvers were used (group 1), and in 23 cases, CVM was used in addition to the no-touch technique (group 2). Demographic data, the status of AC, graft diameter, width, and formation of graft rolls and UT were recorded and compared between the groups. The causes of increased UT and the reason for using CVM were investigated in group 2.

RESULTS

Although an unstable AC was observed more frequently in group 2, the difference between the groups was not statistically significant (P=0.054). Unfolding time of rolls in group 2 was significantly shorter than group 1 (P=0.040).

CONCLUSION

Cannula vacuuming maneuver shortens the UT of the graft roll in the AC and facilitates the graft unfolding maneuvers in complicated cases.

Descemet Membrane Endothelial Keratoplasty (DMEK) in Previously Vitrectomized Eyes: Complications and Clinical Outcomes

PURPOSE

To evaluate the results and complications of Descemet membrane endothelial keratoplasty (DMEK) in previously vitrectomized eyes.

DESIGN

Retrospective study of 35 eyes that had undergone DMEK, due to Fuchs endothelial corneal dystrophy (FECD), at our department with a follow-up after 6 months postoperatively. We compared the intraoperative procedure, complications, and results of DMEK between 14 previously vitrectomized pseudophakic eyes (group 1) and a control group of 21 pseudophakic non-vitrectomized eyes (group 2).

RESULTS

The unfolding time (in minutes) was significantly longer in group 1 than in group 2 (10.5 ± 6.4 vs. 3.2 ± 1.5, p < 0.01). A single re-bubbling was needed in 8 patients in group 1 (57.1%) and in 3 patients in group 2 (14.2%) (p < 0.01). Repeated re-bubbling (≥ 1 time) was performed in only 5 patients of group 1 (35.7%). There was significant postoperative improvement in best-corrected visual acuity (BCVA, in LogMAR) in both groups (p = 0.04 in group 1 and p < 0.01 in group 2). The central corneal thickness (CCT, in µm) did not differ significantly between the two groups preoperatively (p = 0.4) or postoperatively (p = 0.1). However, the CCT decreased significantly postoperatively in both groups (p < 0.01 in both groups). The postoperative endothelial cell density (ECD in cell/mm²) was significantly lower in group 1 than in group 2 (p = 0.03).

CONCLUSION

DMEK in previously vitrectomized eyes presents a surgical challenge, which requires special, and sometimes unpredictable, intraoperative maneuvers, but good functional and morphological results can be achieved. The use of the endothelial Descemet membrane lamellae (EDML) of older donors might be recommended to facilitate the intraoperative unfolding process.

Descemet Membrane Endothelial Keratoplasty for corneal decompensation due to migrating metallic intracorneal foreign bodies in an aphakic eye following a 39-year-old blast injury: A case report

Purpose

To report the use of Descemet Membrane Endothelial Keratoplasty (DMEK) for secondary surgical removal of intraocular foreign bodies (IOFB) years after the trauma as migration occurred through the endothelium, damaging the endothelium, and causing corneal edema.

Observations

We report the case of a blast injury in 1972, that led to left eye traumatic cataract managed with vitrectomy and lensectomy. Although thorough removal was attempted, some corneal and conjunctival foreign bodies remained.

Despite aphakia, the patient maintained acceptable best corrected visual acuity (BCVA) (0.30 LogMAR) but >30 years later, experienced visual deterioration. IOFB protruding through the Descemet membrane (DM) were seen, with extensive edema. Descemet Membrane Endothelial Keratoplasty was performed in an attempt to treat the endothelium and remove the foreign bodies protruding through the DM. The procedure was done uneventfully under sulfur hexafluoride gas (SF6) and the patient improved. Four years after the surgery, BCVA was 0.63, however, 6 years later, a new episode of migrating intracorneal foreign bodies with corneal edema reduced BCVA to 0.40. The decision was made to observe the patient, and delay a second DMEK.

Conclusions and importance

Corneal decompensation caused by IOFB breaching the Descemet membrane can safely be managed with a DMEK. DMEK is feasible even in complex cases and should be attempted due to its lower risk of graft rejection and likely benefits, while saving the option of more aggressive transplantation techniques, such as penetrating keratoplasty, in cases of failure.

Descemet membrane endothelial keratoplasty in vitrectomized eyes: a case series of outcomes and complications

BACKGROUND

The aim of this study was to evaluate the clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) in vitrectomized eyes.

METHODS

A multi-surgeon, retrospective case series of previously vitrectomized eyes that underwent DMEK between 2013 and 2018 at Moorfields Eye Hospital. Patients' demographics, preoperative, intraoperative and postoperative data were collected.

RESULTS

In total, 14 eyes of 13 patients, aged 63 ± 14.6 years were included. Three eyes had intraoperative posterior dislocation of the DMEK graft into the vitreous cavity, two of these were aphakic and one had an unstable PCIOL. Postoperatively, one graft had a total detachment and required repeat keratoplasty for primary failure, two grafts had visually significant partial detachment and needed rebubbling. Three patients developed high intraocular pressure (IOP) and one required an urgent glaucoma drainage device 1-month post-DMEK. The mean corrected distance visual acuity was 0.81 ± 0.42 logMAR preoperatively, and postoperatively was 0.6 ± 0.51 at 3 months (p = 0.414); 0.69 ± 0.81 at 6 months (p = 0.684); and 0.7 ± 0.8 at 12 months (p = 0.658).

CONCLUSIONS

DMEK in vitrectomized eyes has unique challenges that necessitate careful preoperative planning. We observed a significant proportion of dislocated grafts in vitrectomized eyes with either unstable IOL or aphakic. Moreover, vitrectomized eyes with secondary glaucoma may be particularly vulnerable to uncontrolled IOP postoperatively and close monitoring is essential to prevent worsening of visual acuity. We recommend that DMEK may not be a feasible option in eyes that are prone to collapse, in particular aphakic vitrectomized eyes, as opposed to DSAEK or penetrating keratoplasty.

Descemet Membrane Endothelial Keratoplasty versus Descemet Stripping Automated Endothelial Keratoplasty in Complicated Vitrectomized Eyes

PURPOSE

Vitrectomized eyes pose a technical challenge when performing endothelial keratoplasty (EK). The aim of the study was to compare outcomes of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK) in complex eyes undergoing pars plana vitrectomy (PPV) prior to or during surgery.

METHODS

This retrospective study included consecutive eyes that underwent pars plana infusion-assisted DMEK or pull-through DSAEK which underwent PPV prior to or during the EK at a tertiary center. Included were eyes with at least 1-year follow-up. The main outcome measures were best-corrected visual acuity (BCVA) and serious adverse events.

RESULTS

Fifty-two eyes (n = 52) with a mean follow-up time of 24.6 ± 7.4 months were included. Both groups were similar in terms of baseline characteristics although the DMEK group had a significantly larger proportion of Fuchs' patients (p = .009). There was no significant difference in postoperative logMAR BCVA between groups at each visit (p > .05 for all). There was a significantly higher proportion of overall serious adverse events (50.0% versus 15.4%, p = .02), retinal detachments (19.2% versus 0.0%, p = .05) and cystoid macular edema (23.1% versus 0.0%, p = .02) following DMEK. Graft detachment occurred more often following DMEK (53.9% versus 11.5%, p = .001) with no significant difference in rebubbling rates (23.1% versus 11.5%, p = .27).

CONCLUSIONS

A significant and similar improvement in BCVA was achieved following DMEK and DSAEK in complex vitrectomized eyes. Patients should be advised regarding the higher rates of potential serious complications associated with a pars plana infusion DMEK in this situation.

Anterior segment reconstruction with artificial iris and Descemet membrane endothelial keratoplasty: a staged surgical approach

PURPOSE

To describe a surgical approach that involves anterior segment reconstruction with CustomFlex Artificial Iris (CAI; HumanOptics, Erlangen, Germany) followed by Descemet membrane endothelial keratoplasty (DMEK) in complex eyes with corneal decompensation.

METHODS

Restrospective case series of eyes that underwent anterior segment restoration involving (1) synechiolysis of peripheral anterior synechiae and excision of iris remnants, (2) securing a well-fixated posterior chamber intraocular lens and (3) suture-fixated or capsular bag placement of CAI. All eyes then underwent DMEK using a pull-through technique with the DMEK EndoGlide (Network Medical Products, Ripon, UK). Main outcomes were successful anterior segment restoration and corneal clarity with central corneal thickness (CCT).

RESULTS

Five eyes of five patients (median age 61 years, range 27-69 years; 60% female) underwent anterior segment reconstruction with CAI implantation (4 suture-fixated), followed by successful DMEK surgery (median 2 months later, range 1-5 months). There were no major intraoperative complications or primary graft failure, with one peripheral graft detachment that underwent a successful re-bubble at 1 week. All eyes had stable CAI implants and DMEK grafts remained clear at last follow-up with reduction in mean central corneal thickness (preoperative: 658±86 µm vs postoperative: 470±33 µm, p=0.005).

CONCLUSION

This pilot study highlights a feasible approach of initial anterior segment reconstruction with CAI implantation, prior to DMEK, in eyes with significant anterior segment abnormalities such as iris damage or extensive peripheral anterior synechiae and corneal decompensation.

Graft Edge Reflection of a Tightly Scrolled Roll Using Endoillumination as a Simple Method for Determining Graft Orientation in Descemet Membrane Endothelial Keratoplasty

PURPOSE

To describe a simple finding that can be used to determine donor tissue orientation in Descemet membrane endothelial keratoplasty (DMEK). This involves the appearance of a highly reflective round curved line from an overlapping graft edge within the anterior chamber using light from an endoilluminator. We here name this Kobayashi sign (K-sign).

METHODS

Twelve consecutive eyes from 12 patients who underwent DMEK were evaluated for the presence of a K-sign. The presence of Berrospi sign (B-sign), a double-line reflection from the peripheral curls of the Descemet membrane (DM) roll that has been reported to be useful for correct graft orientation, was also evaluated.

RESULTS

Of 12 cases, 3 donors showed a loosely scrolled roll soon after DM donor insertion; all 3 of these showed a positive B-sign only when the endoilluminator was used. Nine donors showed a tightly scrolled DM roll without a B-sign; among these 9 donors, a K-sign was visible in 7 cases only when the endoilluminator was used. The remaining 2 cases with a tight scroll configuration showed no K-sign even with the use of endoillumination, indicating that the roll edge was located completely downward; rotation of the roll using a small jet of fluid from paracentesis revealed K-sign in these cases.

CONCLUSIONS

This technique is useful for determining the correct orientation of a tightly scrolled DM roll, subsequently enabling rapid DMEK surgery. For loosely scrolled DM roll, endoillumination enhanced B-sing is proven useful.

Optical characteristics after Descemet membrane endothelial keratoplasty: 1-year results

PURPOSE

To evaluate the corneal characteristics after Descemet membrane endothelial keratoplasty (DMEK) compared with normal corneas.

METHODS

Patients who underwent DMEK at Yokohama Minami Kyosai Hospital were included and prospectively evaluated pre-operatively and at postoperative months 1, 3, 6, and 12, and compared to healthy controls. Corneal characteristics evaluated included corneal curvature (keratometric value [KV]; D), central corneal thickness (CCT), peripheral corneal thickness (PCT), and corneal higher-order aberrations [HOAs] at 6.0 mm diameter, calculated by anterior segment optical coherence tomography and logarithm of the minimal angle of resolution [logMAR].

RESULTS

A total of 30 eyes of 30 patients (6 men, 24 women, mean age 73.4 ± 7.4 years) were included and compared with 31 age-matched healthy control eyes (13 men, 18 women; mean age 73.0 ± 6.7 years). LogMAR after DMEK improved from 0.87 ± 0.07 preoperatively to 0.04 ± 0.07 at 12 months postoperatively (p<0.001). Although anterior KVs of DMEK eyes were similar to those of control eyes, posterior KVs were significantly larger (-6.4 ± 0.3 D vs. -6.3 ± 0.2 D; p = 0.02). Total HOAs after DMEK improved from 1.94 ± 1.05 μm preoperatively to 1.05 ± 0.16 μm at 12 months postoperatively (p<0.001), which was significantly higher than that in control eyes (0.63 ± 0.06) (p<0.001). Despite the similar CCTs in the two groups, the PCT was significantly larger in DMEK eyes (704 ± 41 μm vs 669 ± 38 μm, p = 0.002) at 12 months.

CONCLUSION

Despite achieving good visual function and excellent corneal clarity, eyes that underwent DMEK showed a steeper posterior KV and higher corneal HOAs than normal eyes even at 12 months after surgery.

[Descemet membrane endothelial keratoplasty DMEK - Donor and recipient step by step]

In 2020 Descemet membrane endothelial keratoplasty (DMEK) has become the gold standard in Germany for the treatment of corneal endothelial diseases; however, the widespread use of DMEK was initially limited due to problems with donor preparation and the difficulty of correctly and gently unfolding the endothelial Descemet membrane (EDM) in the anterior chamber. Following the situational donor selection, the safe single-handed donor preparation of the cornea without tearing or even rupturing the EDM, including the indispensable peripheral semicircular orientation marking. Also presented is a step by step atraumatic loading of the glass cartridge, the introduction of the EDM roll into the anterior chamber, and its safe step by step unfolding based on (1) the sequential use of jets of fluid, (2) repeated tapping on the peripheral/central cornea, (3) controlled flattening of the anterior chamber, (4) use of air bubbles of defined size and finally, the fixation of the EDM in correct orientation to the back of the host cornea with a gas bubble. Since every wrong step with DMEK can have far-reaching consequences for patient and surgeon, this step by step pragmatic approach should minimize the incidence of donor tissue damage and failure in patient maneuvers.

Optimizing pre-Descemet endothelial keratoplasty technique

Pre-Descemet endothelial keratoplasty (PDEK) is an alternative technique to Descemet membrane endothelial keratoplasty (DMEK). The preparation of PDEK tissue by pneumatic dissection is simple and reproducible. The PDEK clamp helps to consistently obtain a type 1 big bubble. The mean size of type 1 big bubble is 7.255 ± 0.535 × 6.745 ± 0.668 mm. The volume of air required to obtain type 1 big bubble is 0.14 to 0.37 mL. Dissection of PDEK tissue can be achieved by trephination or manual excision. Insertion of tissue into the recipient eye can be by injection or pulling. Unfolding techniques used for PDEK are similar to those used in DMEK. Unlike DMEK, PDEK tissue is easier to handle and unscroll and allows use of younger donors. It could help surgeons converting to endothelial keratoplasty, with significant advantages in preparation, handling, and unscrolling in the eye.