Intraoperative OCT-Assisted DMEK: 14 Consecutive Cases

Can high-resolution optical coherence tomography provide an optical biopsy for ocular surface lesions?

High-resolution optical coherence tomography (HR-OCT) has transformed the diagnosis and management of ocular surface lesions. Providing a detailed cross-sectional view of the cornea and conjunctiva, HR-OCT can be used to identify characteristic features of various benign and malignant ocular surface lesions, aiding in their diagnosis and guiding treatment. When incorporated into an ophthalmology clinic, HR-OCT provides morphological images of lesions in a noninvasive means, akin to an "optical biopsy". The characteristic HR-OCT features of several lesions have been well described in the literature, including for ocular surface squamous neoplasia, papilloma, melanoma, primary acquired melanosis, complexion associated melanosis, nevus, pterygium, pinguecula, lymphoma, and amyloidosis. HR-OCT can be used to differentiate between lesions with similar clinical features, lesions that co-exist on the same ocular surface, and atypically presenting lesions, such as pigmented ocular surface squamous neoplasia or amelanotic melanoma. The management of ocular surface lesions has been transformed by the implementation of HR-OCT, providing clinicians with the ability to monitor tumor response to topical chemotherapies, follow previously excised lesions for recurrence, and map out tumor borders intraoperatively. While there are some limitations to HR-OCT, including imaging of thick or deep lesions, it has become an essential tool for ocular oncologists in the management of ocular surface lesions.

Descemet Membrane Endothelial Keratoplasty in Corneal Endothelial Decompensation After a Forceps-Induced Corneal Birth Injury: Case Series and Technique

PURPOSE

The aim of this study was to describe the efficacy of Descemet membrane endothelial keratoplasty (DMEK) in patients with corneal endothelial decompensation secondary to a forceps-induced corneal birth injury.

METHODS

This was a retrospective, noncomparative, interventional case series. Four eyes of 4 patients (1 female and 3 males; mean age, 64.0 ± 4.7 years) with corneal endothelial decompensation due to forceps-induced corneal birth injury were included. DMEK was performed in all cases, using a combined technique, including the use of intraoperative optical coherence tomography, vital staining of Descemet membrane of both host and donor, removal of scarred Descemet membrane with side-port forceps and vitreous cutter to smoothen the posterior corneal surface, epithelial peeling, and illumination for visualization. The examination included preoperative and postoperative ophthalmologic examinations: best-corrected visual acuity (converted to logarithm of the minimum angle of resolution [logMAR]), intraocular pressure, endothelial cell density (ECD), and central corneal thickness.

RESULTS

No postoperative complications were noted, and corneal transparency was maintained during follow-up (mean follow-up period, 32.0 ± 27.0 months; range, 3-71 months). The mean best-corrected visual acuity was 0.52 ± 0.35 logMAR preoperatively and 0.15 ± 0.09 logMAR at the last visit. The mean postoperative ECD was 1632 ± 631 cells/mm 2 (mean ECD at baseline, 3167 cells/mm 2 ). Central corneal thickness decreased from 640 ± 67 μm preoperatively to 576 ± 58 μm postoperatively.

CONCLUSIONS

This study suggests that DMEK can be performed uneventfully in eyes with a forceps-induced corneal birth injury. The combination of surgical techniques may be an effective approach for DMEK.

DMEK surgical training: An instructional guide on various wet-lab methods

Descemet membrane endothelial keratoplasty (DMEK) is a partial-thickness corneal transplantation procedure that involves selective transplantation of the Descemet membrane and endothelium. DMEK offers significant advantages over other keratoplasty techniques, such as faster visual rehabilitation, better final visual acuity due to minimal optical interface effects, lower risk of allograft rejection, and less long-term dependence on topical steroids. Despite all its advantages, DMEK has been found to be more challenging than other corneal transplantation techniques, and its steep learning curve appears to be an obstacle to its widespread use and adoption by corneal surgeons worldwide. DMEK surgical training laboratories (wet labs) provide a window of opportunity for surgeons to learn, prepare, manipulate, and deliver these grafts in a risk-free environment. Wet labs are a significant learning tool, especially for those institutions that have limited tissue availability in their local centers. We provide a step-by-step guide for preparing DMEK grafts using different techniques on human and nonhuman models with instructional videos. This article should eventually help the trainees and the educators understand the requirements for performing DMEK and conducting a DMEK wet lab and develop their skills and interests from a wide variety of available techniques.

Intraoperative OCT for Lamellar Corneal Surgery: A User Guide

Intraoperative OCT is an innovative and promising technology which allows anterior and posterior segment ocular surgeons to obtain a near-histologic cross-sectional and tomographic image of the tissues. Intraoperative OCT has several applications in ocular surgery which are particularly interesting in the context of corneal transplantation. Indeed, iOCT images provide a direct and meticulous visualization of the anatomy, which could guide surgical decisions. In particular, during both big-bubble and manual DALK, the visualization of the relationship between the corneal layers and instruments allows the surgeon to obtain a more desirable depth of the trephination, thus achieving more type 1 bubbles, better regularity of the plane, and a reduced risk of DM perforation. During EK procedures, iOCT supplies information about proper descemetorhexis, graft orientation, and interface quality in order to optimize the postoperative adhesion and reduce the need for re-bubbling. Finally, mushroom PK, a challenging technique for many surgeons, can be aided through the use of iOCT since it guides the correct apposition of the lamellae and their centration. The technology of iOCT is still evolving: a larger field of view could allow for the visualization of all surgical fields, and automated tracking and iOCT autofocusing guarantee the continued centration of the image.

Outcomes of the advanced visualization in corneal surgery evaluation trial; a non-inferiority randomized control trial to evaluate the use of intraoperative OCT during Descemet membrane endothelial keratoplasty

Objective

To evaluate if an intraoperative-OCT (iOCT) optimized surgical protocol without prolonged overpressure is non-inferior to a standard protocol during Descemet membrane endothelial keratoplasty (DMEK).

Methods

Sixty-five pseudophakic eyes of 65 patients with Fuchs endothelial dystrophy scheduled for routine DMEK were recruited in this prospective non-inferiority international multicenter randomized control trial. Subjects were randomized to the control arm (n=33) without iOCT-use and raising the intraocular pressure above normal physiological limits for 8 minutes (i.e., overpressure) or the intervention arm (n=32) with OCT-guidance to assess graft orientation and adherence, while refraining from prolonged overpressure. The primary outcome was the incidence of postoperative surgery-related adverse events (AE). The non-inferiority margin was set at a risk difference of 10%. Secondary outcomes included iOCT-aided surgical decision making, surgical times, and endothelial cell density (ECD) corrected distance visual acuity (CDVA) at 6 months follow-up.

Results

In the intervention group, 12 subjects developed 13 AEs compared to 13 AEs in 10 subjects in the control group (P=0.644). The risk difference measured -0.32% (95%CI: -10.29 - 9.84). The ECD and CDVA did not differ between the two groups 3 and 6 months postoperatively (P=>0.05). Surgeons reported that iOCT aided surgical decision-making in 40% of cases. Surgery and graft unfolding time were, respectively, 13% and 27% shorter in the iOCT-group.

Conclusions

iOCT-guided DMEK surgery with refraining from prolonged over-pressuring was non-inferior compared to conventional treatment. Surgery times were reduced considerably and iOCT aided surgical decision-making in 40% of cases. Refraining from prolonged overpressure did not affect postoperative ECD or CDVA.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT03763721 (NCT03763721).

Clinical outcomes of Descemet membrane endothelial keratoplasty performed in eyes with keratoconus and corneal endothelial dysfunction

PURPOSE

To evaluate the clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) performed in eyes with comorbid keratoconus (KCN) and corneal endothelial dysfunction.

METHODS

Twenty-five consecutive eyes of 14 patients with comorbid stable KCN underwent DMEK for corneal endothelial dysfunction; best spectacle corrected visual acuity (BSCVA), maximum corneal curvature (Kmax), maximum corneal power (Pmax), central corneal thickness (CCT), and intra- and postoperative complications were assessed.

RESULTS

Excluding eyes requiring re-transplantation for primary graft failure (n = 3), all eyes showed improvement in BSCVA, reaching ≥ 20/40 (0.5) in 86%, ≥ 20/25 (0.8) in 55%, and ≥ 20/20 (1.0) in 27% by one month postoperatively; 90%, 76%, and 48% by 6 months postoperatively; and 88%, 76%, and 47% by 12 months postoperatively. CCT decreased from 571μm preoperatively to 485μm at 1 month (p < 0.001) and 481μm at 12 months (p < 0.001). Kmax decreased by a median of 1.4 diopters (D) at 1 month (p = 0.003) and 3.1 D at 12 months (p = 0.021), and every eye with a preoperative Kmax ≥ 46 D demonstrated flattening. Pmax decreased by 2.1 D at 1 month (p = 0.001) and 4.0 D at 12 months (p = 0.016).

CONCLUSION

DMEK is technically feasible in eyes with comorbid KCN and may give excellent outcomes visual and refractive outcomes, including significant corneal flattening, which may potentially create a visually significant hyperopic shift in patients with severely ectatic corneas.

Long-Term Results of Postoperative Rescuing of Inverted DMEK Grafts: Two Case Reports

PURPOSE

The purpose of this study was to report the clinical outcomes of postoperative repositioning of 2 inverted Descemet membrane endothelial keratoplasty (DMEK) grafts in 2 patients with endothelial dysfunction.

METHODS

Two patients underwent DMEK surgery in a tertiary referral corneal clinic. Initial surgery was performed by 2 different corneal surgeons, and a third surgeon repositioned both cases. In the early postoperative period, partial and subtotal detachments were observed at slitlamp and inverted graft orientation was confirmed by anterior segment optical coherence tomography. In both cases, uneventful reposition of the inverted graft was performed by an experienced DMEK surgeon on days 2 and 9 after initial DMEK surgery.

RESULTS

Repositioning surgery was successful in both patients. The Moutsouris sign was used to confirm proper orientation. One patient had total graft adherence at day 1 postrepositioning. The second patient required a rebubbling procedure, despite the correct orientation confirmed by using anterior segment optical coherence tomography. Visual acuity and corneal thickness were stable in both cases (case 1: 20/30, 567 μm; case 2: 20/80, 543 μm). Both patients had clear corneas and functional cell counts 2 years after repositioning (451 cells/mm 2 and 1052 cells/mm 2 ).

CONCLUSIONS

Postoperative repositioning of an inverted DMEK graft may be a viable procedure to delay or prevent regrafting.

The Development and Clinical Application of Innovative Optical Ophthalmic Imaging Techniques

The field of ophthalmic imaging has grown substantially over the last years. Massive improvements in image processing and computer hardware have allowed the emergence of multiple imaging techniques of the eye that can transform patient care. The purpose of this review is to describe the most recent advances in eye imaging and explain how new technologies and imaging methods can be utilized in a clinical setting. The introduction of optical coherence tomography (OCT) was a revolution in eye imaging and has since become the standard of care for a plethora of conditions. Its most recent iterations, OCT angiography, and visible light OCT, as well as imaging modalities, such as fluorescent lifetime imaging ophthalmoscopy, would allow a more thorough evaluation of patients and provide additional information on disease processes. Toward that goal, the application of adaptive optics (AO) and full-field scanning to a variety of eye imaging techniques has further allowed the histologic study of single cells in the retina and anterior segment. Toward the goal of remote eye care and more accessible eye imaging, methods such as handheld OCT devices and imaging through smartphones, have emerged. Finally, incorporating artificial intelligence (AI) in eye images has the potential to become a new milestone for eye imaging while also contributing in social aspects of eye care.

Automatic evaluation of graft orientation during Descemet membrane endothelial keratoplasty using intraoperative OCT

Correct Descemet Membrane Endothelial Keratoplasty (DMEK) graft orientation is imperative for success of DMEK surgery, but intraoperative evaluation can be challenging. We present a method for automatic evaluation of the graft orientation in intraoperative optical coherence tomography (iOCT), exploiting the natural rolling behavior of the graft. The method encompasses a deep learning model for graft segmentation, post-processing to obtain a smooth line representation, and curvature calculations to determine graft orientation. For an independent test set of 100 iOCT-frames, the automatic method correctly identified graft orientation in 78 frames and obtained an area under the receiver operating characteristic curve (AUC) of 0.84. When we replaced the automatic segmentation with the manual masks, the AUC increased to 0.92, corresponding to an accuracy of 86%. In comparison, two corneal specialists correctly identified graft orientation in 90% and 91% of the iOCT-frames.

Application of Intraoperative Optical Coherence Tomography Technology in Anterior Segment Surgery

The use of optical coherence tomography (OCT) technology in anterior segment diseases allows for precise assessment of the changes following anterior segment surgery. Advances in microscope-integrated OCT systems have allowed the utilization of intraoperative OCT (iOCT) in anterior segment surgeries, i.e., cornea, cataract, and refractive surgery. iOCT has enabled real-time precise visualization of anterior segment tissues as well as interactions between surgical instruments and ocular tissue; thus, the device can facilitate surgical procedures and provide valuable information for decision-making during anterior segment surgeries. In this review, the authors will introduce studies regarding the development of iOCT technology and its application in various anterior segment surgeries. Multiple studies have shown the efficacy of the iOCT for intraoperative assistance and guidance, suggesting the potential of the device for optimizing the surgical outcomes after cornea, cataract, and refractive surgery.

An Overview of Intraoperative OCT-Assisted Lamellar Corneal Transplants: A Game Changer?

Intraoperative optical coherence tomography (iOCT) is a noninvasive imaging technique that gives real-time dynamic feedback on surgical procedures. iOCT was first employed in vitreoretinal surgery, but successively served as a guidance in several anterior segment surgical approaches: keratoplasty, implantable Collamer lens (ICL) implantation, and cataract surgery. Among all of those approaches, the unbeatable features of iOCT are fully exploited in anterior and posterior lamellar keratoplasty, and the purpose of this review is to focus on the advantages and shortfalls of iOCT in these techniques, in order to assess whether this technology could be a real step forward. In deep anterior lamellar keratoplasty (DALK), iOCT is useful to evaluate the needle depth into the corneal stroma, the big bubble dissection plane, and residual stromal bed, thus aiding the standardization of the technique and the reduction of failures. In Descemet stripping automated endothelial keratoplasty (DSAEK), iOCT allowed for clear visibility of fluid at the graft/host interface, allowing for immediate rescue maneuvers and granting the best graft apposition. In Descemet membrane endothelial keratoplasty (DMEK), iOCT can track the lenticule unfolding in real time and assess graft orientation even in severe hazy corneas, thus optimizing surgical times, as well as avoiding the use of potentially hazardous exterior markers (such as the “S” stamp) and preventing unnecessary manipulation of the graft. Overall, the role of iOCT appeared crucial in several complicated cases, overcoming the difficulties of poor visualization in a fast, non-invasive way, thus raising this approach as possible gold standard for challenging conditions. Further improvements in the technology may enable autonomous centering and tracking, overcoming the current constraint of instrument-induced shadowing.

Current Perspectives on Corneal Transplantation

Disease of the cornea is the third leading cause of blindness worldwide. Corneal graft surgery is one of the most successful forms of solid organ transplantations in humans, with ever-increasing developments in surgical technique. To date, approximately 4504 corneal transplants are performed in the United Kingdom each year. While full thickness transplantation was the most commonly performed keratoplasty over the last few decades, selective lamellar transplantation of the diseased layers of the cornea has been universally adopted. This comprehensive review aims to provide an updated synthesis on different types of corneal transplantations, their treatment outcomes, and the associated complications of each procedure in both adult and paediatric population. In addition, we also present an up-to-date summary of the emerging therapeutic approaches that have the potential to reduce the demand for donor-dependent keratoplasty.

Clinical applications for intraoperative optical coherence tomography: a systematic review

In this systematic review, we provide an overview of the current state of intraoperative optical coherence tomography (iOCT). As iOCT technology is increasingly utilized, its current clinical applications and potential uses warrant attention. Here, we categorize the findings of various studies by their respective fields, including the use of iOCT in vitreoretinal surgery, corneal surgery, glaucoma surgery, cataract surgery, and pediatric ophthalmology. The trend observed in recent decades towards performing minimally invasive ophthalmic surgery has caused practitioners to recognize the limitations of using a conventional surgical microscope for intraoperative visualization. Thus, the superior visualization provided by iOCT can improve the safety of these surgical techniques and promote the development of new minimally invasive ophthalmic surgeries. Landmark prospective studies found that iOCT can significantly affect surgical decision making and can cause a subsequent change in surgical strategy, and the use of iOCT has potential to improve surgical outcome. Despite these advantages, however, iOCT is still a relatively new technique, and beginning users of iOCT can encounter limitations that can preclude their reaching the full potential of iOCT and in this respect several improvements are needed.

INTRAOPERATIVE OPTICAL COHERENCE TOMOGRAPHY -AVAILABLE TECHNOLOGIES AND POSSIBILITIES OF USE. A REVIEW

Optical coherence tomography (OCT) is a non-contact and non-invasive imaging and diagnostic method, that allows the imaging of ocular tissues on transverse sections in extremely high quality of micrometer resolution. The physical principle of OCT is analogous to ultrasound, but it uses infrared radiation instead of acoustic waves. By using a low coherent radiation source, it is possible to achieve a higher resolution. Based on the obtained data, the computer can reconstruct two or three-dimensional images of the examined tissue. In recent years, we have seen a rapid development in ophthalmic surgery, especially in surgical instruments and imaging methods. However, the technology of surgical microscopes does not change significantly and thus becomes a limiting factor in the development of ophthalmic microsurgery. The integration of the OCT into surgical microscopes, so the introduction of the Intraoperative Optical Coherence Tomography (iOCT), opens up further possibilities for displaying/looking at the operating field and adapting surgical techniques to the current situation during the surgery. On the contrary, the disadvantage is the prolongation of the surgery time and thus the theoretical increase in possible complications related to the surgery. iOCT can be used for operations on the anterior and posterior segment of the eye. In anterior segment surgery, it is used mostly in penetrating and lamellar keratoplasty, glaucoma surgery and cataract surgery. In posterior segment surgery, it is used during pars plana vitrectomy. The aim of the article is to provide a comprehensive overview of the current possibilities of using iOCT in eye surgery.

Correlation between intraoperative and postoperative vaulting of the EVO implantable Collamer lens: a retrospective study of real-time observations of vaulting using the RESCAN 700 system

Background

Implantable Collamer lens (ICL) vaulting is one of the most important parameters for the safety, aqueous humor circulation, and lens transparency after ICL implantation. This study aimed to investigate the factors associated with the actual vaulting after refractive EVO-ICL surgery.

Methods

This retrospective study included patients who underwent EVO-ICL surgery at a tertiary eye hospital between October and December 2019. A RESCAN 700 was used for the intraoperative and CIRRUS HD-OCT was used for postoperative observation of vaulting. Subjective and objective refractions, anterior ocular segment, corneal morphology, intraocular pressure (IOP), anterior chamber volume (ACV), crystalline lens rise (CLR), white-to-white distance (WTW), anterior chamber depth (ACD), axial length, corneal endothelial cell density (ECD), and fundoscopy were examined. A multivariable analysis was performed to determine the factors independently associated with 1-month postoperative vaulting.

Results

Fifty-one patients (102 eyes) were included. Compared with the eyes with normal vaulting, those with high vaulting had higher preoperative diopter values (P = 0.039), lower preoperative corrected visual acuity (P = 0.006), lower preoperative IOP (P = 0.029), higher preoperative ACD (P = 0.004), lower preoperative CLR (P = 0.046), higher ICL spherical equivalent (P = 0.030), higher intraoperative vaulting (P < 0.001), and lower IOP at 1 month (P = 0.045). The multivariable analysis showed that the only factor independently associated with high vaulting at 1 month after surgery was the intraoperative vaulting value (odds ratio = 1.005, 95% confidence interval: 1.002–1.007, P < 0.001). The intraoperative and 1-month postoperative vaulting values were positively correlated (R² = 0.562).

Conclusions

The RESCAN700 system can be used to perform intraoperative optical coherence tomography to predict the vaulting value of ICL at 1 month.

Marking DMEK Grafts Using Bandage Contact Lens Interface Technique: Doubling the Utilization During the Acute Shortage of Donor Corneas

PURPOSE

The purpose of this study was to describe a novel bandage contact lens (BCL) interface technique for marking the Descemet membrane endothelial keratoplasty (DMEK) graft so that a single donor cornea can be used effectively for 2 recipients during acute shortage.

METHODS

This was a retrospective comparative case series. In group A, 37 eyes underwent DMEK using a graft marked by the [DOUBLE HIGH-REVERSED-9 QUOTATION MARK]BCL interface technique" that was compared with 49 conventional DMEK grafts marked through the stromal window (group B). In group A, a resized BCL with a central 3-mm hole with the concavity up was placed between the stroma and peeled-off DM. This BCL with DM was flipped for S-stamping on the DM side. Final trephination was performed on a second Teflon block. The remaining anterior lamellar tissues of group A were used on the same day for other keratoplasty procedures. Endothelial cell density (ECD) and endothelial cell loss between the 2 groups were compared after 3 and 6 months.

RESULTS

The ECD at 3 months in group A (n = 35) versus group B (n = 45) was 2228 ± 270/mm2 versus 2302 ± 254/mm2 (P = 0.48), and the ECD at 6 months (n = 23 and 22) was 2058 ± 324/mm2 versus 2118 ± 260/mm2 (P = 0.72). The corresponding endothelial cell loss was 23.3% ± 6.8% versus 20.3% ± 6.1% (P = 0.18) at 3 months and 29.1% ± 8.4% versus 26.7% ± 8.0% (P = 0.34) at 6 months. Among anterior tissues of group A, 17 (45.9%) were used for deep anterior lamellar keratoplasty, 18 (48.6%) were used for larger therapeutic and tectonic grafts, and 2 were used as keratoprosthesis carriers. Donor detachment rate (8.6% vs. 8.9%) was similar in both groups without primary graft failures.

CONCLUSIONS

The BCL interface technique is a simple and safe technique for stamping DMEK grafts. Anterior corneal tissues can be used for additional keratoplasties during donor shortage.

Clinical results after single asymmetrical shark fin for graft orientation in DMEK

PURPOSE

Evaluating the effect of a single peripheral triangular mark to ensure the correct anterior-posterior graft orientation in DMEK.

METHODS

Retrospective study of patients scheduled for DMEK due to Fuchs endothelial dystrophy and divided into 2 study groups: Group -M (n = 184) had no mark of the EDM (Endothelial Descemet membrane) and group + M (n = 193) had a triangular peripheral mark. Follow-up time was 1 year after surgery.

RESULTS

The postoperative graft turning and Re-DMEK rate could be significantly reduced by the use of a peripheral mark (p = 0.002, p = 0.001, respectively). Re-DMEK due to primary graft failure was significantly associated with prior graft turning (p < 0.001). Both groups showed comparable values for visual acuity, central corneal thickness and endothelial cell count after a follow-up of 1 year.

CONCLUSION

Single peripheral triangular marking is a simple and cost-saving addition to EDM preparation to ensure the correct orientation of the graft intraoperatively and could lead to a significant reduction in graft turning and re-DMEK rate in this study.

Three-quarter DMEK in eyes with glaucoma draining devices to avoid secondary graft failure

PURPOSE

To present a case series of a modified three-quarter Descemet's membrane endothelial keratoplasty (3/4-DMEK) technique to treat pseudophakic bullous keratopathy in the presence of a glaucoma drainage device (GDD) tube in the anterior chamber by reducing the risk of donor endothelial damage due to absence of donor endothelial cells overlying the GGD tube area.

METHODS

In this prospective case series, four eyes of three patients with stable glaucoma underwent 3/4-DMEK surgery for pseudophakic bullous keratopathy after GDD insertion. The patients were followed up to 24 ± 2.5 months postoperatively.

RESULTS

No intraoperative or postoperative complications were noted. The average central endothelial cell density (ECD) was 1093 ± 74 cells/mm² at 12 months postoperatively, corresponding to an ECD decrease of 58 (±6)% as compared to preoperative values. Average best-corrected visual acuity increased from finger counting before surgery to 20/60 (logMar 0.5) at 12 months after 3/4-DMEK and remained stable up to 24 months postoperatively. All corneas remained clear at the last available follow-up.

CONCLUSION

This case series demonstrates the technical feasibility of 3/4-DMEK in eyes with pseudophakic bullous keratopathy in the presence of a GDD tube. The absence of a donor DM and donor cells above the silicone tube excludes direct tube contact with the graft. Longer term studies are needed to show the effect of this modified graft pattern and dimensions on transplant survival.

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.

Intraoperative Versus Postoperative Vault Measurement After Implantable Collamer Lens Implantation in a Large Cohort of Patients

PURPOSE

To compare intraoperative and postoperative central vault measurement after implantable Collamer lens (ICL; STAAR Surgical) implantation using optical coherence tomography (OCT).

METHODS

A total of 574 eyes of 338 consecutive patients undergoing myopic ICL implantation were evaluated (mean age of 30.8 ± 5.7 years, 117 men and 221 women). Central ICL vault was measured both intraoperatively using the microscope-integrated iOCT (Optomedical Technologies GmbH) mounted on a standard surgical microscope (HS Hi-R NEO 900A; Haag-Streit Surgical GmbH), and postoperatively using the CASIA2 swept-source OCT (Tomey GmbH) at 4 and 24 hours.

RESULTS

Mean differences between intraoperative and postoperative vault values were 11.5 ± 29.0% of the mean value 4 hours postoperatively (P < .001) and 2.7 ± 33.5% of the mean value 24 hours postoperatively (P < .001). Correlation analysis shows significant agreement between vault values obtained intraoperatively and at the two postoperative times, 4 hours (Spearman Rho = 0.850, P < .001) and 24 hours (Spearman Rho = 0.745, P < .001). In 73% of cases, postoperative vault values 4 hours after the surgery could be predicted from intraoperative vault values, and so were 56% of vault values 1 day after surgery. Significant differences in vault were found at the different times, grouping cases by ICL size (Kruskal-Wallis, P = .028 for intraoperative vault, and P < .001 for both postoperative vault times), with smaller vault values for the smaller ICL size.

CONCLUSIONS

Intraoperative determination of ICL vault using iOCT is an effective method for predicting postoperative ICL vault and minimizing postoperative vault surprises that could require surgical retouching. [J Refract Surg. 2021;37(7):477-483.].

Intraoperative optical coherence tomography guided corneal sweeping for removal of remnant Interface fluid during ultra-thin Descemet stripping automated endothelial keratoplasty

BACKGROUND

Remnant interface fluid following Descemet stripping automated endothelial keratoplasty (DSAEK) is associated with postoperative detachments. The aim of this study was to assess outcomes of intraoperative optical coherence tomography (iOCT) guided meticulous peripheral corneal sweeping for removal of interface fluid during ultra-thin (UT) DSAEK.

METHODS

This retrospective study included all eyes underwent iOCT guided UT-DSAEK from October 2016 to February 2018 at the Hanusch Hospital, Vienna, Austria. Peripheral meticulous corneal sweeping was performed to remove excess fluid. Central graft thickness (CGT) was measured prior to surgery, after graft bubbling and after corneal sweeping. Remnant interface fluid rates were compared between eyes that underwent rebubbling and those that did not.

RESULTS

Overall, 28 eyes of 28 patients with a mean age of 73.9 ± 10.0 years were included. An iOCT guided meticulous peripheral sweeping was performed in 89.3% (n = 25) of the cases. Following 84% (n = 21) of the peripheral sweeping performed, remnant fluid was no longer identified. Following peripheral sweeping the interface fluid height was reduced from 17.31 ± 15.96 μm to 3.46 ± 9.52 μm (p < 0.001) and CGT was reduced by 7% (p < 0.001). Rebubbling was performed in 17.9% (n = 5) of the cases. The rebubbling group had a greater proportion of patients that had remnant fluid identified with iOCT at the end of surgery despite meticulous peripheral sweeping (60.0% versus 4.4%, p = 0.01).

CONCLUSION

The iOCT identified subclinical remnant fluid in nearly 90% of UT-DSAEK cases. An iOCT guided peripheral corneal sweeping led to resolution of interface fluid in a majority of cases. Eyes with persistent remnant fluid despite peripheral corneal sweeping are more likely to require subsequent rebubbling.

Agreement between intraoperative anterior segment spectral-domain OCT and 2 swept-source OCT biometers

Purpose: To evaluate the agreement of different biometric parameters obtained using intraoperative spectral-domain optical coherence tomography (SD-OCT) and two swept-source optical coherence tomography (SS-OCT) based biometers.Methods: 102 eyes were assessed using the intraoperative SD-OCT integrated into the Catalys femtosecond-laser, and the IOLMaster 700 and Anterion SS-OCT-based-biometers. Central corneal thickness (CCT), anterior chamber depth (ACD), white-to-white (WTW), and lens thickness (LT) were measured.Results: There were statistically significant differences for CCT, ACD, WTW and LT between devices (p < 0.001). The mean difference for ACD ranged from -0.067 to -0.250 mm, with the largest mean difference being between the IOLMaster 700 and Catalys. CCT mean differences ranged from 7 to 32 µm, with the largest mean difference being between the Anterion and Catalys. For WTW, the comparison between the IOLMaster 700 vs Catalys showed the largest mean difference (0.38 mm). However, the mean differences for LT from all three devices were quite similar, ranging from -0.02 to -0.08 mm.Conclusions: SS-OCT biometers showed good agreement for ACD, CCT, WTW and LT. The SD-OCT showed ACD, CCT and WTW values that do not seem to be interchangeable with the SS-OCT biometers; however, this device did show excellent agreement in the case of LT.

Non stripping descemet membrane endothelial keratoplasty in difficult cases: A case series

Endothelial keratoplasty (EK) has been increasingly used instead of penetrating keratoplasty (PK) in the management of post PK graft rejection. Both DSAEK and DMEK involve the surgical removal of the diseased host endothelial cell layer and Descemet's membrane (DM) (descemetorhexis) before transplantation, a technically challenging step, especially in post-PK eyes. Understandably, interest arose when non-stripping DMEK (nDMEK) was described in 2013, and recent studies suggested encouraging results without increased early postoperative failures or complications requiring rebubbling. The purpose of our series was to further study the feasibility and safety of nDMEK and to compare the results with traditional DMEK. This is a single center case series of 3 eyes which underwent nDMEK performed by experienced surgeons (C.P, A.M). Two eyes had nDMEK as a secondary procedure following a failed/rejected PK, while the third case underwent nDMEK on a virgin eye. Undiseased donor DM and a regular host endothelium were required to be eligible for nDMEK. The average change in CCT at last follow-up was -21.2% (±13.3). All required intracameral air injection (rebubbling) within the first few days, with a mean of 2.33 rebubblings per eye, the first one occurring at 6.33±2.52 days after surgery. Non-stripping DMEK surgery appears to be a feasible option, and results are satisfactory at mid to long term. However, in our series, the immediate postoperative period was marked by an increased rebubbling rate. While foreseeable particularly in high-risk cases, surgeons considering this technique should expect a higher risk of early rejection.

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.

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

PURPOSE

To evaluate the intraoperative use of ultrasound biomicroscopy (UBM) during Descemet's membrane endothelial keratoplasty (DMEK) to determine graft's orientation.

METHODS

Prospective interventional study of eight eyes of seven patients who underwent DMEK. Following the identification of correct graft orientation using 'Blue cannula tip' sign during DMEK surgery, UBM was used to ascertain graft's orientation. The rate of successful DMEK graft orientation determined by the UBM was registered and verified postoperatively by anterior segment-optical coherence tomography (OCT). Intra- and postoperative complications, postoperative clearance of the cornea, corrected distance visual acuity and endothelial cell loss were also noted.

RESULTS

The study included five males and two females aged 54-82 years with corneal oedema due to Pseudophakic bullous keratopathy (n = 5), Fuchs' endothelial dystrophy (n = 2). In all cases, the technique allowed proper determination of the graft's orientation. In one case, 'blue cannula tip' sign showed correct orientation while UBM identified an upside-down graft. The graft was inverted in the anterior chamber using fluid jets, and repeat 'blue cannula tip' sign and UBM examination both showed correct orientation. In all cases, postoperative anterior segment-OCT demonstrated correct graft orientation.

CONCLUSIONS

Use of intraoperative UBM to determine graft orientation during DMEK correlated with proper graft orientation, as was verified postoperatively by anterior segment-OCT. The use of UBM can be particularly helpful in cases of poor graft visibility due to opaque corneal stroma, pigment or blood in the anterior chamber during surgery, or when the blue tint of the graft fades rapidly, which may preclude proper determination of graft's orientation.

Fuchs endothelial corneal dystrophy: The vicious cycle of Fuchs pathogenesis

Fuchs endothelial corneal dystrophy (FECD) is the most common primary corneal endothelial dystrophy and the leading indication for corneal transplantation worldwide. FECD is characterized by the progressive decline of corneal endothelial cells (CECs) and the formation of extracellular matrix (ECM) excrescences in Descemet's membrane (DM), called guttae, that lead to corneal edema and loss of vision. FECD typically manifests in the fifth decades of life and has a greater incidence in women. FECD is a complex and heterogeneous genetic disease where interaction between genetic and environmental factors results in cellular apoptosis and aberrant ECM deposition. In this review, we will discuss a complex interplay of genetic, epigenetic, and exogenous factors in inciting oxidative stress, auto(mito)phagy, unfolded protein response, and mitochondrial dysfunction during CEC degeneration. Specifically, we explore the factors that influence cellular fate to undergo apoptosis, senescence, and endothelial-to-mesenchymal transition. These findings will highlight the importance of abnormal CEC-DM interactions in triggering the vicious cycle of FECD pathogenesis. We will also review clinical characteristics, diagnostic tools, and current medical and surgical management options for FECD patients. These new paradigms in FECD pathogenesis present an opportunity to develop novel therapeutics for the treatment of FECD.

Corneal transplantation after failed grafts: Options and outcomes

Corneal transplantation is the most commonly performed human tissue transplantation procedure worldwide. Because of the large number of transplants, corneal graft failure has become one of the most common indications for corneal transplantation. The relatively recently developed lamellar transplant techniques have brought about specific potential complications leading to graft failure that may require different approaches to repeat transplantation other than penetrating keratoplasty. On the other hand, these new lamellar techniques also provide novel ways of rescuing failed penetrating grafts, with potential advantages over successive penetrating keratoplasties, such as reduced intraoperative risks and faster visual rehabilitation. We summarize the incidence and risk factors of graft failure for penetrating and lamellar (stromal and endothelial) corneal transplants and discuss the various surgical alternatives currently available to rescue such failed grafts, with a focus on the reported outcomes and limitations.

Corneal endothelial dysfunction: Evolving understanding and treatment options

The cornea is exquisitely designed to protect the eye while transmitting and focusing incoming light. Precise control of corneal hydration by the endothelial cell layer that lines the inner surface of the cornea is required for optimal transparency, and endothelial dysfunction or damage can result in corneal edema and visual impairment. Advances in corneal transplantation now allow selective replacement of dysfunctional corneal endothelium, providing rapid visual rehabilitation. A series of technique improvements have minimized complications and various adaptations allow use even in eyes with complicated anatomy. While selective endothelial keratoplasty sets a very high standard for safety and efficacy, a shortage of donor corneas in many parts of the world restricts access, prompting a search for alternatives. Clinical trials are underway to evaluate the potential for self-recovery after removal of dysfunctional central endothelium in patients with healthy peripheral endothelium. Various approaches to using cultured human corneal endothelial cells are also in clinical trials; these aim to multiply cells from a single donor cornea for use in potentially hundreds of patients. Pre-clinical studies are underway with induced pluripotent stem cells, endothelial stem cell regeneration, gene therapy, anti-sense oligonucleotides, and various biologic/pharmacologic approaches designed to treat, prevent, or retard corneal endothelial dysfunction. The availability of more therapeutic options will hopefully expand access around the world while also allowing treatment to be more precisely tailored to each individual patient.

Intraoperative Optical Coherence Tomography Imaging in Corneal Surgery: A Literature Review and Proposal of Novel Applications

Intraoperative optical coherence tomography (iOCT) is widely used in ophthalmic surgeries for cross-sectional imaging of ocular tissues. The greatest advantage of iOCT is its adjunct diagnostic efficacy, which facilitates to decision-making during surgery. Since the development of microscopic-integrated iOCT (MIOCT), it has been widely used mainly for vitreoretinal and anterior segment surgeries. In corneal transplantation, MIOCT allows surgeons to visualise structure underneath the turbid and distorted cornea, which are impossible to visualise with a usual microscope. Real-time visualisation of hard-to-see area reduces the operation time and leads to favorable surgical outcomes. The use of MIOCT is advantageous for a variety of corneal surgical procedures. Here, we have reviewed articles focusing on the utility of iOCT  and MIOCT in penetrating keratoplasty, deep anterior lamellar keratoplasty, Descemet stripping automated endothelial keratoplasty, and Descemet membrane endothelial keratoplasty. The applications of MIOCT to corneal surgery in terms of surgical education for trainees, emergency surgery, and novel surgery are also discussed, with our cases performed using RESCAN^® 700.

Intraoperative Optical Coherence Tomography Guided Ocular Surgeries: Critical Analysis of Clinical Role and Future Perspectives

Intraoperative imaging of ocular tissues for diagnostic and therapeutic applications has gained immense admiration in recent years. The real time cross-sectional imaging, as well as three and four dimensional reconstruction abilities of intraoperative optical coherence tomography (iOCT), has enhanced our knowledge on many fronts in surgical maneuvers. In this review, we discuss the iOCT discovered constructive knowledge in the cornea, cataract, refractive, glaucoma, pediatric ocular, and various retinal conditions. The practical utility with decision modifying aspects along the specified ocular tissues and with respect to specific ocular entities have been narrated. Moreover, limitations and future directions have also been emphasized to make ophthalmic care more comprehensive in the future.

Intraoperative optical coherence tomography in anterior segment surgery

Intraoperative optical coherence tomography (iOCT) enables real-time visualization of ocular structures during surgery and enhances our understanding of intraoperative dynamics. iOCT aids in decision-making during various anterior segment surgeries, and its efficacy and feasibility in anterior lamellar keratoplasty and endothelial keratoplasty is well established. The landmark DISCOVER study observed that iOCT altered the surgeon decision in 38% of cases undergoing lamellar keratoplasty and provided guidance regarding the need for secondary surgical intervention. iOCT also finds an application in phacoemulsification wherein it helps to assess corneal incisions, intralenticular pressure, and posterior capsule integrity during nuclear emulsification. iOCT aids in the visualization of angle structures during placement of tubes and shunts in glaucoma surgeries and allows precise creation of partial thickness scleral flaps. In addition, iOCT helps in establishing a diagnosis, as well as provide intraoperative guidance, in pediatric patients who are not cooperative for examination. The role of iOCT in refractive surgeries and ocular surface disorders is increasingly being evaluated. The limitations of present-day iOCT systems are related to instrument compatibility, automated tracking of the surgical field, and on-table volumetric analysis of the real-time images. Technological advances may facilitate complete integration of OCT in the surgical microscopes for all surgical procedures.

Heads-up Descemet Membrane Endothelial Keratoplasty Surgery: Feasibility, Surgical Duration, Complication Rates, and Comparison With a Conventional Microscope

PURPOSE

To assess the feasibility of Descemet membrane endothelial keratoplasty (DMEK) surgery using the glasses-assisted 3-dimensional (3D) display system NGENUITY (Alcon Laboratories, Fort Worth, TX) and to compare with standard DMEK surgery by using a conventional operating microscope.

METHODS

Twelve consecutive cases of DMEK surgery were performed using the glasses-assisted 3D display system NGENUITY (Alcon) and matched with similar cases performed by using the OPMI-Lumera 700 surgical microscope (Carl Zeiss Meditec, Jena, Germany) in this prospective cross-sectional study realized at the Rothschild Foundation, Paris, France. DMEK graft preparation time, graft unfolding time, time to perform the descemetorhexis (DM), and overall surgical time were recorded. Best corrected visual acuity, endothelial cell density of the donor tissue measured by specular microscopy, and the recipient's central corneal thickness were recorded preoperatively and again at 1 and 3 months postoperatively.

RESULTS

In the 3D group, time to perform the graft preparation, DM, and global surgical time were significantly higher in the 3D group than in the conventional groups (17 minutes 36 seconds ± 3 minutes 13 seconds and 14 minutes 50 seconds ± 1 minutes 28 seconds, P = 0.04; 6 minutes 18 seconds ± 2 minutes 30 seconds vs. 3 minutes 50 seconds ± 2 minutes 8 seconds, P = 0.03; and 31 minutes 30 seconds ± 6 minutes 10 seconds vs. 24 minutes 10 seconds ± 3 minutes 26 seconds, respectively, P = 0.05). The time to unfold the graft was higher, although not significantly so, in the 3D group compared with the conventional group (5 minutes 15 seconds ± 2 minutes 40 seconds vs. 4 minutes 40 seconds ± 2 minutes 25 seconds, P = 0.89). Mean central corneal thickness decreased about 168 ± 82 μm at 3 months after surgery in the 3D group and about 228 ± 123 μm in the conventional group without significant difference (P = 0.60). Best corrected visual acuity in the 3D group was 0.33 ± 0.32 LogMAR at 3 months after surgery with no significant differences found when compared with conventional surgery. The percent endothelial cell loss from preoperative at 3 months was 35% in the 3D group and 26% in the conventional group, respectively, with no significant difference (P > 0.05).

CONCLUSIONS

Performing DMEK surgery using a 3D display system is feasible; however, it is more challenging and the total surgical time is longer. This method would certainly be useful for instructional courses.

Comparison of the Success Rate of Two Different Marking Techniques (F-Mark and Asymmetric Triangular Mark) to Orient the Donor Graft During Descemet Membrane Endothelial Keratoplasty

OBJECTIVES

We evaluated the effects of various graft-marking techniques on surgical results in patients undergoing Descemet membrane endothelial keratoplasty.

MATERIALS AND METHODS

In this single-center retrospective study, 65 eyes from 55 patients that had received various types of marking or no marking and that had been used for Descemet membrane endothelial keratoplasty endothelial graft preparation were included. Patients were divided into 3 groups according to the marking technique used: group I (F-marked graft; 17 eyes), group II (asymmetric triangle-marked graft; 12 eyes), and group III (unmarked graft; 36 eyes). The main outcome measurements were best-corrected visual acuity, endothelial cell density, central corneal thickness, postoperative complications, rebubbling, and secondary keratoplasty rates.

RESULTS

In groups I, II, and III, rates of patients with 6-month best-corrected visual acuity ≥ 20/32 were 35.7%, 77.8%, and 71.9%, respectively (P = .04). The mean 6-month endothelial cell density decrease for each group was 43.3%, 48.8%, and 46.4%, respectively (P = .589), whereas the mean 6-month central corneal thickness decrease for each group was 7.7%, 15.8%, and 34.0%, respectively (P = .001). Rates of primary graft failure for groups I, II, and III were 35.3%, 8.3%, and 13.9%, respectively. Rebubbling was performed in 21.5% of eyes, and secondary keratoplasty was required in 29.2% of eyes.

CONCLUSIONS

Although graft-marking techniques for Descemet membrane endothelial keratoplasty greatly facilitate graft positioning during surgery, both the potential toxic effects of alcohol on the endothelium when marking with gentian violet dye and the risk of graft detachment with asymmetric marking must be considered.

What Is the Impact of Intraoperative Microscope-Integrated OCT in Ophthalmic Surgery? Relevant Applications and Outcomes. A Systematic Review

Background: Optical coherence tomography (OCT) has recently been introduced in the operating theatre. The aim of this review is to present the actual role of microscope-integrated optical coherence tomography (MI-OCT) in ophthalmology. Method: A total of 314 studies were identified, following a literature search adhering to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. After full-text evaluation, 81 studies discussing MI-OCT applications in ophthalmology were included. Results: At present, three microscope-integrated optical coherence tomography systems are commercially available. MI-OCT can help anterior and posterior segment surgeons in the decision-making process, providing direct visualization of anatomic planes before and after surgical manoeuvres, assisting in complex cases, and detecting or confirming intraoperative complications. Applications range from corneal transplant to macular surgery, including cataract surgery, glaucoma surgery, paediatric examination, proliferative diabetic retinopathy surgery, and retinal detachment surgery. Conclusion: The use of MI-OCT in ophthalmic surgery is becoming increasingly prevalent and has been applied in almost all procedures. However, there are still limitations to be overcome and the technology involved remains difficult to access and use.

Management of Upside-Down Descemet Membrane Endothelial Keratoplasty: A Case Series

Purpose

To present the management of upside-down Descemet membrane endothelial keratoplasty (DMEK) following combined phacoemulsification with DMEK (phaco-DMEK) in cases of Fuchs endothelial dystrophy (FED).

Methods

This is a comparative interventional case series extracted from a prospective interventional case series (clinical outcome of DMEK combined with phacoemulsification for FED). We report five cases of upside-down DMEK. Two cases of upside-down DMEK were managed with re-orientation and the other two with repeat DMEK. The 5^th case underwent an initial re-orientation and then a subsequent repeat graft. Graft re-orientation and repeat surgery were performed 9-20 days after initial phaco-DMEK. All the five cases were followed up over a 6-month period, and the following outcomes were assessed: best corrected visual acuity (BCVA), contrast sensitivity (CS), central corneal thickness, endothelial cell density (ECD), and central macular thickness.

Results

At the final 6-month postoperative follow-up, all the five cases achieved good outcomes in terms of BCVA and CS. Overall, the results were comparable to 32 control cases. One case of re-orientation and the case of re-orientation with subsequent repeat DMEK performed slightly less well than control cases in terms of postoperative ECD.

Conclusions

Re-orientation of the original DMEK scroll in cases of upside-down DMEK can be a safe and cost-effective alternative to repeat DMEK. If re-orientation does not result in corneal deturgescence, a repeat DMEK may be done subsequently.

Microscope Integrated Intraoperative Optical Coherence Tomography-Guided DMEK in Corneas with Poor Visualization

PURPOSE

To assess the utility of microscope-integrated intraoperative optical coherence tomography (Mi-OCT) for performing Descemet membrane endothelial keratoplasty (DMEK) in corneas with poor visualization.

METHODS

It is a prospective interventional case series that included 25 consecutive cases of corneal decompensation with poor visualization that underwent Mi-OCT-guided DMEK at a tertiary eye care centre. The main outcome measures were graft attachment on day 3 and requirement for re-bubbling.

RESULTS

The etiology for corneal decompensation was pseudophakic bullous keratopathy (n=17), Fuchs endothelial corneal dystrophy (n=4), failed graft (n=2), iridocorneal endothelial syndrome (n=1) and failed Descemet stripping automated endothelial keratoplasty (n=1). Complete graft attachment was noted in 72% of cases. Graft detachment was noted in 16% of cases which required re-bubbling. No intervention was done for shallow peripheral detachment (n=2) and peripheral Descemet membrane (DM) fold (n=1). All grafts were attached at six-months follow-up. The mean corrected distance visual acuity and central corneal thickness improved from 1.4 ± 0.5 logMAR and 799.6 ± 110.9 µm at baseline to 0.3 ± 0.3 logMAR and 536.28 ± 11.44 um at six months. Mi-OCT was helpful in visualizing areas of peripheral anterior synechiae, missing DM, retained DM tags after descemetorhexis, DMEK roll configuration and orientation in the injector and anterior chamber, interface fluid and peripheral folds in the DMEK graft.

CONCLUSION

Mi-OCT helps in identification of the anatomy and dynamics of the host DM, DM roll and anterior chamber in cases with poor visualization and is a useful tool while performing DMEK in such cases.

Intraoperative Optical Coherence Tomography-Assisted Descemet Membrane Endothelial Keratoplasty in the DISCOVER Study: First 100 Cases

PURPOSE

Intraoperative optical coherence tomography (iOCT) may facilitate successful transition to Descemet membrane endothelial keratoplasty (DMEK) surgery via improved efficiency of tissue orientation. The purpose of this study is to report a large consecutive series of iOCT-assisted DMEK, inclusive of all learning curve cases.

DESIGN

Prospective consecutive case series.

METHODS

The Determination of Feasibility of Intraoperative Spectral Domain Microscope Combined/Integrated OCT Visualization During En Face Retinal and Ophthalmic Surgery (DISCOVER) study is a single-site, multisurgeon, IRB-approved investigational device prospective study. The first 100 consecutive iOCT-assisted DMEK surgeries performed by 1 attending corneal surgeon (JMG) and 6 novice surgeons (cornea fellows under supervision) were reviewed. iOCT was utilized for tissue orientation. Patient demographics, tissue characteristics, intraoperative parameters, and postoperative complications are reported.

OUTCOMES

(1) Utility of iOCT based on surgeon reporting during surgery, (2) intraoperative graft unscrolling efficiency, and (3) frequency of postoperative complications.

RESULTS

One hundred eyes of 76 patients were enrolled. Forty-three cases were performed by 1 staff physician and 57 cases were performed by 6 cornea fellows. Concurrent phacoemulsification with lens implantation was performed in 52 cases (52%). Nine eyes (9%) required rebubbling. Two eyes (2.0%) experienced primary graft failure. One graft failure resulted from surgeon error in interpreting the iOCT. Average unscrolling time was 4.4 ± 4.1 minutes (range: 0.7-27.6 minutes).

CONCLUSIONS

iOCT facilitates DMEK orientation without the need for external markings. For novice DMEK surgeons, complication rates and unscrolling times compare favorably with alternative tissue orientation methods.

Intra-operative optical coherence tomography in glaucoma surgery-a systematic review

The application of the OCT in clinical ophthalmology has expanded significantly since its introduction more than 20 years ago. There has been recent growing interest in the application of intra-operative optical coherence tomography (iOCT). The iOCT's ability to enhance visualisation and depth appreciation has the potential to be further exploited in glaucoma surgery, especially with the emergence of Minimally Invasive Glaucoma Surgery (MIGS)-to facilitate targeted device placement and fine surgical manoeuvres in the angles, the sub-conjunctival layer and the suprachoroidal space. Hence, this study aims to appraise the current literature on the applications of iOCT in glaucoma surgery. A total of 79 studies were identified following a literature search adhering to PRISMA guidelines. After full text evaluation, 10 studies discussing iOCT use in glaucoma surgery were included. Traditional glaucoma filtering procedures reviewed included trabeculectomy surgery, goniosynechiolysis, bleb needling and glaucoma drainage device implantation. MIGS procedures reviewed included canaloplasty, trabecular aspiration, ab-interno trabectome and the XEN45 gel stent. iOCT use in ophthalmic surgery is becoming increasingly prevalent and has already been applied in various surgeries and procedures in the field of glaucoma. With the greater adoption of MIGS, iOCT may further contribute in facilitating surgical techniques and improving outcomes. While iOCT offers many advantages, there are still limitations to be overcome-iOCT technology continues to evolve to optimise imaging quality and user-experience.

How to Avoid an Upside-Down Orientation of the Graft during Descemet Membrane Endothelial Keratoplasty?

Purpose

Incorrect anterior-posterior orientation of the Descemet endothelial complex (DEC) is one of the causes of failure of Descemet membrane endothelial keratoplasty (DMEK). We evaluated a new marking technique to avoid such a misorientation.

Method

A new marking technique of the DEC was evaluated in patients requiring primary DMEK. A Braille-“R”-letter was applied dot by dot onto the stromal surface of the DEC after lifting it by injecting an air-bubble into the interface between the endothelial surface of the partially stripped graft. The positioning of the graft was intraoperatively controlled by an orientation of the Braille-“R”-letter. Laboratory tests were conducted to test the impact of the marking technique on endothelial cell count.

Results

We included prospectively 37 eyes of 30 patients. Four eyes were phakic and 33 pseudophakic. Five grafts (14%) presented an undifferentiated rolling tendency in the anterior chamber, and evaluation of their positioning was possible due to orientation of the mark alone. In case of an upside-down orientation, grafts were flipped immediately. A correct orientation of the graft was achieved in all cases at the end of the surgery. The endothelial cell loss due to the mark was estimated to be less than 0.3%. At 3- and 6-month follow-ups, the mean best-corrected visual acuity was 0.21 ± 0.15 and 0.15 ± 0.11 logMAR, respectively, and endothelial cell density was 1661 ± 349 and 1618 ± 396 cells/mm², respectively. Only one patient (3%) needed re-bubbling.

Conclusions

To rely on the natural rolling tendency of the graft alone does not assure its correct positioning in all cases. Creation of the mark with 4 dots punctuated on the air-lifted stromal side of the DEC is a simple and endothelial cell saving marking method to ensure correct orientation of the graft during DMEK.

[Transplantation of endothelium and Descemet's membrane]

Nowadays, endothelial keratoplasty has become an alternative to penetrating keratoplasty (PKP) in the management of corneal endothelial dysfunction. Descemet membrane endothelial keratoplasty (DMEK) is a relatively new corneal transplantation surgery technique suited for patients with endothelial insufficiency, an increasing number of surgeons are learning the graft preparation technique and the surgery itself after seeing its excellent postoperative visual outcomes and faster rehabilitation of patients. DMEK has significant advantages in comparison with automated and manual Descemet Stripping Endothelial Keratoplasty (DSAEK/DSEK) and PKP including lower risk of immunologic graft rejection (1-2%), lower cost of the procedure, and it does not require expensive equipment such as a microkeratome or a femtosecond laser device. Another advantage is that the corneal graft tissue can be used for several recipients - e.g. when the Descemet's membrane and endothelium are used for a patient with endothelial dysfunction of the cornea, the retained stroma and epithelium can be then used for another patient with pathology of these corneal layers. Key problematic issues regarding this surgery are the technical difficulties during graft preparation and during surgery itself, however the majority of surgeons report very good results after gaining some experience. The article reviews latest clinical trials on DMEK and describes its strengths and weaknesses.

Does Fluid Temperature Affect Corneal Endothelium-Descemet Membrane Scroll Formation? An In Vitro Study

Objectives:

To investigate whether unfolding time of Descemet membrane (DM) graft rolls changes at various fluid temperatures.

Materials and Methods:

The study was prospective, ex vivo, and experimental. The study was conducted at the tertiary center for corneal disease in Adana Numune Training and Research Hospital between June 2014 and June 2015. DMs were divided into 4 categories according to baseline roll tightness and these were distributed among 4 different groups using 4 different balanced salt solution (BSS) temperatures (8, 16, 23, and 36 °C). Sixteen donor corneas were obtained from the hospital eye bank.

Results:

DM roll formations may vary according to the donor cornea received. Some form tighter rolls while others can form a more open roll. No differences in roll tightness were observed in any of the DM rolls after 5 or 10 minutes in the different BBS temperatures. In all groups, neither tightening nor opening was observed in DM roll formations.

Conclusion:

Different BSS temperatures were found to have no effects on DM unfolding time in this study.

Postoperative Repositioning of Inverted Descemet Membrane Endothelial Keratoplasty Grafts

PURPOSE

To present 4 cases of postoperative repositioning of inverted grafts after Descemet membrane endothelial keratoplasty (DMEK).

METHODS

Retrospective case reports of 4 patients presenting with subtotal to total graft detachment after DMEK, most probably owing to upside-down graft positioning. Graft repositioning was performed 1 to 14 days after initial DMEK surgery. In 3 cases (cases 1, 3, and 4), repositioning was performed without removing the graft from the anterior chamber (AC), whereas for case 2, the graft had to be removed from the AC to attain correct graft orientation.

RESULTS

In all 4 cases, the initially upside-down DMEK grafts could be successfully repositioned postoperatively. Three cases showed complete graft attachment after graft repositioning with clear corneas until the last available follow-up. One case manifested a persistent central detachment with central corneal edema, eventually requiring re-DMEK. Endothelial cell density decreased from 2800 cells/mm preoperatively to 2373 cells/mm at 2 years postoperatively for case 1 and from 2600 to 600 cells/mm at 6 months postoperatively for case 2. Case 3 showed a clear cornea until the last available follow-up at 1 year postoperatively.

CONCLUSIONS

In cases of upside-down grafts after DMEK, attempting to reposition the graft, with or without removing the graft from the AC, may be a cost- and tissue-efficient alternative before converting to re-DMEK.

BrightOcular® Cosmetic Iris Implant: A Spectrum from Tolerability to Severe Morbidity

Purpose

The BrightOcular® implants are the newest model of cosmetic iris devices that are currently advertised as safe. The previous generation known as NewColorIris® have had severe ocular side effects and were subsequently withdrawn from the market. There is little literature on the safety profile of BrightOcular® implants.

Case Report

Herein we describe two cases with varying degrees of ocular tolerability. The first case had a normal ocular exam 1 year after implantation, whereas the second case had unilateral severe corneal edema requiring explantation of the iris device and Descemet membrane endothelial keratoplasty 9 months after bilateral implantation.

Conclusions

These two cases attest to the unpredictability of the results of these cosmetic surgeries. Patients should be counseled about the vision-threatening complications of iris implants.