Article

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

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Abstract

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, multi-surgeon, IRB-approved investigational device prospective study. The first 100 consecutive iOCT-assisted DMEK surgeries performed by one attending corneal surgeon (JMG) and six 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. 3. Frequency of post-operative complications. Results: One hundred eyes of 76 patients were enrolled. Forty-three cases were performed by one staff physician and 57 cases were performed by six cornea fellows. Concurrent phacoemulsifcation 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.

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... One promising surgery to reap the benefits of iOCT is Descemet membrane endothelial keratoplasty (DMEK) (3)(4)(5)(6). DMEK is considered the standard in endothelial keratoplasty (7)(8)(9). Despite its advantages, the rate of postoperative adverse events (AEs) for DMEK is relatively high with a reported prevalence of 20% for rebubbling and~5% for primary graft failure (9)(10)(11)(12). ...
... During DMEK surgery the iOCT provides valuable feedback in evaluating graft-host apposition, faster graft positioning with fewer manipulations, and verifying graft orientation in DMEK (3)(4)(5). These insights led to the conceptualization of an iOCT-optimized DMEK surgical protocol by our group, consisting of iOCTguidance during unfolding and refraining from prolonged overpressuring of the globe. ...
... In line with similar reports, we found that the iOCT enables the surgeon in a 27% faster unfolding and positioning of the graft. Though not assessed in this study a shorter duration of unfolding and positioning the graft may be related to less manipulation of the graft and improved graft viability and survival (3)(4)(5). Efficiency gains from refraining from overpressure and a faster unfolding time may be offset by the time taken to assess the iOCT images. Future development in automated image analysis may aid to reduce this offset (1,27,28). ...
Article
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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.ResultsIn 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.ConclusionsiOCT-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 registrationhttps://clinicaltrials.gov/ct2/show/NCT03763721 (NCT03763721).
... Currently, the Moutsouris sign, ink-stamps, and circular cuts are used to determine intraocular graft orientation [4,[7][8][9]. However, poor visualization of the anterior chamber and graft hinders a proper assessment [10][11][12]. In addition, the presence of the Moutsouris sign is not always self-evident and both stamps and cuts damage the graft resulting in endothelial cell loss. ...
... In addition, the presence of the Moutsouris sign is not always self-evident and both stamps and cuts damage the graft resulting in endothelial cell loss. More recently, intraoperative optical coherence tomography (iOCT) has been used to determine graft orientation, as the iOCT signal is not perturbed by corneal edema [10][11][12][13][14]. Residual stromal fibers in the Descemet's membrane of the DMEK graft result in a distinctive inward curve of the graft's ends indicative of a correct orientation, which can be visualized and assessed using iOCT (Fig. 1.) [13][14][15]. ...
... Several studies have reported on the use of iOCT during DMEK surgery for determining the orientation of the graft. In all studies the graft orientation could be correctly determined based on the inward rolling of the graft edges visible on the cross-sectional iOCT image [10,12,14,16]. Importantly, the surgeon was able to assess the graft orientation in cases where assessment of the Moutsouris sign or S-stamp was challenging or not possible [10][11][12]. ...
Article
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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.
... One promising surgery to reap the benefits of iOCT is Descemet membrane endothelial keratoplasty (DMEK). [3][4][5][6] DMEK is a recent iteration of endothelial keratoplasty and reported advantages include faster visual recovery, superior visual acuity, and reduced rates of endothelial rejection compared to Descemet stripping endothelial keratoplasty. [7][8][9] Despite these advantages the rate of postoperative adverse events (e.g., graft detachment requiring rebubbling) for DMEK is relatively high with a reported prevalence of ranging between 2% and 82% for rebubbling and 3% and 11% for primary graft failure. ...
... 23 iOCT enables surgeons to directly assess graft adherence, the need for additional surgical manoeuvres, and facilitates DMEK orientation without the need for external markings that may damage the graft and increase the risk of complications. 5,6 In the PIONEER and DISCOVER study Ehlers et al. reported that iOCT aided and altered clinical decision making in, respectively, 48 and 43% of corneal surgeries. 24,25 The iOCT provided valuable feedback in evaluating graft-host apposition, graft positioning, and verifying graft orientation in DMEK. ...
... In a pilot study, the incidence of postoperative adverse events was lower and operation time was shorter using this protocol. 6 Notwithstanding, in this pilot protocol changes were gradually introduced and a control without iOCT guidance was missing. The promising results warranted followup in a head-to-head comparison with a conventional surgical protocol. ...
Preprint
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Purpose 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). Design A multicenter international prospective non-inferiority randomized control trial Subjects Sixty-five pseudophakic eyes of 65 patients with corneal endothelial dysfunction resulting from Fuchs endothelial corneal dystrophy were enrolled in 3 corneal centers in The Netherlands and Belgium. Methods The study was powered to include 63 patients scheduled for routine DMEK. 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 raising the intraocular pressure. The RD and 95% confidence intervals (95% CI) were calculated from a logistic regression model using 1,000 bootstrap samples. Secondary outcomes included the incidence of graft detachment, surgeon-reported iOCT-aided surgical decision making, surgical time, endothelial cell density (ECD), and corrected distance visual acuity (CDVA). Main Outcome Measures The primary outcome was the incidence of postoperative surgery-related adverse events, defined as rebubbling, graft failure, and iatrogenic acute glaucoma. The non-inferiority margin was set at a risk difference (RD) of 10%. Results In the control group, 13 adverse events were recorded in 10 subjects compared to 13 adverse events in 12 subjects in the intervention group. The mean unadjusted RD measured 0.38% (95%CI: - 9.64–10.64) and the RD adjusted for study site measured -0.32% (95%CI: -10.29–9.84). No significant differences in ECD and CDVA were found between the two groups 3 and 6 months postoperatively. Surgeons reported that iOCT aided surgical decision-making in 40% of cases. Surgical- 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 surgeons reported the iOCT aided surgical decision-making in 40% of cases. Refraining from prolonged overpressure did not affect postoperative ECD or CDVA.
... Furthermore, iOCT can be useful while determining orientation, unfolding, and positioning the graft during DMEK [84,88,89]. Proper orientation of the graft must be determined in order to ensure functional graft adhesion (Fig. 5). ...
... Proper orientation of the graft must be determined in order to ensure functional graft adhesion (Fig. 5). Currently used signs/ methods (e.g., the Moutsouris-sign, stamps or circular cuts) are not always self-evident and poor visualization hinder proper assessment [88,89]. Not to mention, both stamps and cuts damage the graft resulting in endothelial cell loss [79]. ...
... The natural rolling behavior of DMEK grafts can be well appreciated on the iOCT image, thereby preventing the need to manipulate, cut, or mark the graft to determine the orientation, subsequently preventing endothelial cell loss. In addition, both Saad et al. and Patel et al. reported that iOCT resulted in a shorter duration for unscrolling and positioning the DMEK graft, thereby reducing graft manipulation and improving surgical efficiency [88,91]. ...
Article
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.
... Microscope integrated OCT-aided visualization [Steven P et al.]. [59][60][61] ...
... [140] In today's date, the literature is replete with both comparative and noncomparative studies, evaluating the outcomes of DMEK in comparison with other forms of endothelial transplantation such as DSAEK and ultrathin DSAEK and as a standalone procedure in various clinical scenarios. Over a e while newer advancements have been incorporated such as the use of intraoperative OCT [61,59] to help in intraoperative and postoperative decision making and the use of femtosecond laser for assisting descemetorhexis. [141] a) Changes in corneal biomechanical and optical properties after DMEK DMEK allows near-normal visual, anatomical as well as ultrastructural rehabilitation without altering the biomechanical properties of the cornea. ...
Article
Full-text available
Descemet membrane endothelial keratoplasty (DMEK) is the closest to the physiological replacement of endothelial cells. In the initial years, the technique was surgically challenging. Over the years, with better understanding and modifications in the surgical steps, the technique has evolved as an alternative to more popular procedure Descemet stripping endothelial keratoplasty. The article highlights the various preoperative, intraoperative, and postoperative nuances of DMEK. Additionally, it summarizes the various comparative and noncomparative studies on DMEK outcomes.
... In DSAEK and DMEK, iOCT can provide critical information from intraoperative decision-making in all surgical steps [7,12,14,19,29,41,42], which may lead to enhanced anatomical and visual outcomes. [10, 12-15, 19, 38] In both DSAEK and DMEK, iOCT can visualize donor-recipient attachment and residual interface fluid, which may help achieve tight apposition and prevent graft dislocation ( Figure 3) [1,7,10,14]. ...
... In DMEK, iOCT can be a valuable tool for verification of graft orientation, particularly in cases with severe corneal edema or haze [5,7,14,15,19,38]. Based on the scrolling configuration of the endothelial graft visualized using iOCT, the DMEK orientation can be easily confirmed prior to the identification of the orienting marker (Figure 3 marking of the donor tissue may become unnecessary, which can be beneficial for the preservation of donor corneal endothelial cells [1,14,15,19,38,41]. iOCT can also help shorten the learning curve for DMEK [12]. ...
Article
Full-text available
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.
... iOCT serves as a guidance tool for key surgical processes in endothelial keratoplasty, from scoring the Descemet membrane to guaranteeing graft apposition at the conclusion of the procedure. For this reason, both Descemet stripping anterior endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) are made easier by intraoperative OCT [21,27,42,43]. ...
... In the last update of the DISCOVER study, those findings were confirmed. Patel et al. noted that iOCT offered helpful real-time feedback in all instances (100%) and did not interfere with the surgical operation in any manner [43]. In all instances, the iOCT picture on the linked external video display was preferred, because of the smaller, lower-definition picture on the inside display. ...
Article
Full-text available
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.
... Several studies have evaluated the utility of iOCT in DMEK surgery. These reports demonstrated that iOCT aided in identifying remnants of host Descemet membrane, identifying and facilitating correct graft orientation [23][24][25]. Recently, Patel et al. reported in a prospective study (n = 100) that for novice DMEK surgeons, complication rates and unscrolling times compared favorably with alternative tissue orientation methods while avoiding the need for external markings [25]. ...
... These reports demonstrated that iOCT aided in identifying remnants of host Descemet membrane, identifying and facilitating correct graft orientation [23][24][25]. Recently, Patel et al. reported in a prospective study (n = 100) that for novice DMEK surgeons, complication rates and unscrolling times compared favorably with alternative tissue orientation methods while avoiding the need for external markings [25]. ...
Article
Full-text available
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.
... To identify the correct graft orientation during surgery, 3point-marking [66], 4-point-marking [83], triangle marking [84], S or F stamps [85][86][87], and OCT-assisted unfolding [88][89][90] have been described worldwide. From Asia, a 4-pointmarking technique with 2 pairs of asymmetrical semicircular marks on the edge of the donor graft has been introduced (Fig. 2a) [83]. ...
... Even in very opaque corneas, intraoperative OCT was helpful in checking and adjusting graft orientation/positioning without the need for peripheral marking. (Fig. 3) [88][89][90]. However, special devices are necessary for intraoperative OCT, which has so far hindered the use of intraoperative OCT as standard in DMEK surgery, at least in the majority of countries. ...
Article
Full-text available
Purpose of Review Descemet membrane endothelial keratoplasty (DMEK) has become the treatment of choice for endothelial diseases such as Fuchs endothelial corneal dystrophy (FECD), especially in the United States and Europe. In this review, we give an overview of current knowledge about DMEK in Asian eyes and describe novel surgical modifications of this technique for these cases. Recent Findings Although many scientific reviews about DMEK in Caucasian eyes have already been published, there is still little knowledge about clinical outcomes of DMEK in Asian eyes. This is of particular importance, as there are substantial differences between DMEK in Asian and Caucasian eyes. Bullous keratopathy is the main indication for endothelial keratoplasty in Asia, whereas it is FECD in Caucasian countries. Considering etiological and anatomical differences, we have adapted DMEK for Asian eyes and have developed several technical modifications to improve clinical outcome. Summary Our work might be helpful in performing successful DMEK in the Asian setting.
... [2][3][4] Results of studies from around the world as well as my own personal experience suggest that ophthalmic surgeons doing complex corneal surgeries, such as endothelial keratoplasty, anterior lamellar keratoplasty, or deep anterior lamellar keratoplasty (DALK), could benefit from the additional information that intraoperative OCT provides. [5][6][7][8][9][10][11] Intraoperative OCT has been available in the United States for several years, either commercially or for investigational use, with 3 manufacturers in the market, Carl Zeiss Meditec USA, Dublin, CA; Leica, Wetzlar, Germany; and Haag-Streit USA, Mason, OH. These devices provide 3 ways to view the OCT image: on a monitor specifically for the OCT unit, as an inset in the video recording, and as an image injected into the oculars. ...
... Intraoperative OCT also facilitates Descemet membrane endothelial keratoplasty (DMEK), 5,[9][10][11] which is our most common keratoplasty procedure. With intraoperative OCT, we do not need to mark the donor tissue, thereby preserving endothelial cells. ...
... Posterior corneal procedures like Descemet stripping (automated) endothelial keratoplasty (DSEK/DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) can also benefit from the use of I-OCT. The handling, unfolding, and positioning of the graft can be performed more quickly and definitively with simultaneous I-OCT, which can also verify its correct orientation (176)(177)(178)(179)(180)(181). Apart from this, fluid between the cornea and the graft (interface fluid) and areas of graft nonadherence or folds can be assessed and addressed (176,(182)(183)(184). ...
Article
Full-text available
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.
... Nanothin DSAEK was introduced to use a ≤50 μm graft that enables a minimal posterior stromal tissue transplant. 6,7 Intraoperative optical coherence tomography (OCT) has been employed for lamellar corneal surgery [8][9][10][11] and other types of ocular surgeries. Microscope-integrated OCT can visualize real-time B scan images, and facilitate surgical decision-making during the operation. ...
Article
Full-text available
Purpose To report use of intraoperative optical coherence tomography (OCT) for nanothin Descemet stripping automated endothelial keratoplasty (DSAEK) in a patient with an extremely thickened cornea due to advanced bullous keratopathy. Observations A 90-year-old woman with a history of multiple trabeculectomies was referred to us for treatment of advanced bullous keratopathy (1400 μm central corneal thickness). Nanothin DSAEK was planned and performed. In brief, after the removal of the loose corneal epithelium, the anterior chamber was meticulously observed using a surgical microscope and oblique light via an endoillumination probe; however, the visibility of the anterior chamber was limited because of severe corneal edema. Subsequently, a nanothin (47 μm) DSAEK graft stained with trypan blue was inserted into the anterior chamber using an NS endoinserter. Intraoperative OCT was used successfully to visualize the graft unfolding, air tamponade, and graft attachment. At 3 months postoperatively, significant corneal clearing (625 μm central corneal thickness), improvement of visual acuity (decimal 0.04), and pain relief were obtained. Conclusions and importance: Intraoperative OCT is useful for nanothin DSAEK even when the surgical microscope view is compromised by a remarkably thickened host cornea due to advanced bullous keratopathy. As an alternative to a penetrating keratoplasty, less invasive nanothin DSAEK was successfully performed.
... Similarly, DMEK donor tissue preparation, its orientation, and configuration, while injecting into theanterior chamber and contemplation of its complete attachment were evidenced on iOCT. 34,35 In 100 cases of DMEK, results on iOCT discussed by Patel et al, 36 revealed the greater advantage for novice surgeons as it reduced the complication and unscrolling time in comparison to senior surgeons. In addition, markings along the graft tissue for orientation were also mitigated. ...
Article
Amar Pujari,* Divya Agarwal,* Rohan Chawla, Atul Kumar, Namrata Sharma Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India*These authors contributed equally to this workCorrespondence: Amar PujariDr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, IndiaTel +91 8447226221Email dramarpujari@gmail.comAbstract: 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.Keywords: intraoperative optical coherence tomography, iOCT, hand-held optical coherence tomography and intraoperative microscope integrated optical coherence tomography
... b Bare sclera after removal of the pterygium (arrow) with corneal edema and impaired visibility for the surgeon. Beneficial effects of iOCT have also been described by other authors [19,20]. Possible beneficial effects regarding the rebubbling rate should be evaluated in studies comparing iOCT to standard methods. ...
Article
Full-text available
Purpose: Recently, intraoperative optical coherence tomography (iOCT) has evolved in the field of ophthalmic surgery. So far, the use of iOCT was mainly focused to lamellar keratoplasty, especially deep anterior lamellar keratoplasty (DALK) and Descemet membrane endothelial keratoplasty (DMEK). The aim of this study was to report our experiences with iOCT to introduce new possibilities of this application. Methods: We used iOCT in 18 patients who underwent the following surgeries: DALK, DMEK, penetrating keratoplasty, autologous limbal transplantation, transscleral suture fixation of a posterior chamber lens, pannus removal on corneal surface and newborn investigation in Peters' anomaly. We obtained qualitative video data for all procedures. Results: With the iOCT, the cannula placement during DALK preparation of the recipient cornea and bubble formation could be visualized to improve the success rate of the big bubble injection. In DMEK, the iOCT enables the visualization of Descemet's membrane removal in the recipient and graft orientation as well as better control of graft attachment. The iOCT enables intraoperative visualization of the graft-host interface during penetrating keratoplasty. During autologous limbal transplantation, transscleral suture fixation of a posterior chamber lens and removal of corneal surface pannus the iOCT is capable of showing the thickness of lamellar preparations to avoid penetrations and to save healthy recipient's tissue. Conclusion: The iOCT is a helpful device for intraoperative anterior segment imaging not only for DALK and DMEK. It is also beneficial in penetrating keratoplasty and every other form of lamellar preparation during corneoscleral surgery.
... A report of the outcomes of the first 100 DMEK procedures in the DISCOVER study described a reduced unfolding time and rebubbling rate using MI-OCT, compared to the average values reported in the literature about DMEK, which was not assisted by MI-OCT, 4.4 min versus 5.7-6.4 min and 6.4% versus 28.8%, respectively [37]. Likewise, Saad et al. reported a rebubbling rate of 7% in a case series of 14 DMEK assisted by MI-OCT [34]. ...
Article
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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.
Article
Background In recent years, great progress has been made in intraoperative imaging using optical coherence tomography (iOCT). There are now several commercially available iOCT systems that allow high-resolution imaging of all structures of the eye without interrupting surgery. This real-time visualisation can provide additional information to conventional surgical microscopy, but is relatively expensive. The aim of our study was to find out how often OCT integrated into the surgical microscope is used by trained surgeons, or to what extent they consider that iOCT is relevant for intraoperative procedures. Patients and Methods A prospective monocentric analysis was conducted of the field of application and user-friendliness of the EnFocus Ultra-Deep OCT (Leica Microsystems), a mobile device combination of surgical microscope and OCT. The use and benefit were investigated of iOCT, which was not mandatory. Standardised documentation and evaluation using a questionnaire was performed by the respective surgeon (n = 5) immediately after surgery. Results Over a period of 25 working days, 118 procedures were performed in the operating theatre equipped with the microscope-OCT combination. The iOCT was used in 24.6% of the 118 procedures performed. iOCT was regarded as crucial to the intraoperative procedure in 3 of the 29 patients. In one patient, it was possible to check graft orientation during a DMEK operation in a very opaque cornea and, in the second patient, to visualise the correct positioning of an iris diaphragm in the capsular bag. In the third patient, the risk of developing a pseudoforamen was assessed, and this led to the decision not to perform a full gliosis peel. Conclusion Experienced surgeons in a university eye hospital with a full surgical spectrum considered that intraoperative OCT was decisive for the course of surgery in only a few selected surgical situations, e.g. in case of limited corneal transparency. The impact of the use of iOCT on post-operative outcome quality still needs to be evaluated by larger prospective studies. On the basis of this survey, the cost-benefit ratio is still unclear.
Article
Intraoperative optical coherence tomography (OCT) has the potential to revolutionize lamellar corneal surgery and facilitate many other types of ocular surgery because it readily visualizes ocular structures that can be difficult to discern with a coaxial microscope, particularly through a cloudy cornea. Systems that can provide a high-quality image on demand in the surgeon's oculars, rather than just on an adjacent monitor, are the most useful because they allow the surgeon to rely on the OCT image while operating, without having to look away from the surgical field. Useful applications in lamellar corneal surgery include assessing graft attachment with Descemet stripping endothelial keratoplasty and discerning graft orientation with Descemet membrane endothelial keratoplasty, which otherwise could be challenging in an eye with a cloudy cornea. Intraoperative OCT is particularly helpful when performing deep anterior lamellar keratoplasty in cases in which a big bubble should not be attempted or cannot be achieved because it enables better intraoperative control of the incision depth and allows the surgeon to assess the uniformity of the dissection plane to optimize visual outcomes. Intraoperative OCT is also useful when judging the depth of a scar for a lamellar dissection, when evaluating intraocular lens positioning in the capsular bag, or when locating and removing retained nuclear fragments from an eye with a poor view because of a cloudy cornea. The primary barrier to the adoption of this valuable technology is cost.
Article
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In April 2019, the US Food and Drug Administration, in conjunction with 11 professional ophthalmic, vision science, and optometric societies, convened a forum on laser-based imaging. The forum brought together the Food and Drug Administration, clinicians, researchers, industry members, and other stakeholders to stimulate innovation and ensure that patients in the US are the first in the world to have access to high-quality, safe, and effective medical devices. This conference focused on the technology, clinical applications, regulatory issues, and reimbursement issues surrounding innovative ocular imaging modalities. Furthermore, the emerging role of artificial intelligence in ophthalmic imaging was reviewed. This article summarizes the presentations, discussion, and future directions.
Article
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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.
Article
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.
Article
PURPOSE: To evaluate whether the speed of stripping a Descemet membrane endothelial keratoplasty graft influences the graft scroll width. METHODS: Human corneas suitable for research were selected for the study. Pairs of corneas were randomly divided into 2 groups: 1 cornea was stripped with a slow speed (group 1) and the contralateral with a fast speed (group 2). Slow speed was defined as the total time greater than 150 seconds or speed <0.057 mm/s. Fast peeling was defined as less than 75 seconds or speed >0.11 mm/s. The grafts acquired were evaluated by microscopy for the graft scroll width and endothelial cell density change pre- and post-preparation. RESULTS: Twenty corneas of 10 donors were included in the analysis. The mean donor age was 68.6 ± 7.58 years. The mean total time of the tissue preparation in group 1 was 282.7 ± 28 seconds and in group 2 was 126 ± 50 seconds (P-value = 0.00000047). The mean speed of stripping in group 1 was 0.045 ± 0.006 mm/s and in group 2 was 0.266 ± 0.093 mm/s (P-value = 0.000027). The graft width in group 1 was 6.4 ± 0.92 mm and in group 2 was 2.87 ± 0.32 mm (P-value = 0.00000014). The mean endothelial cell loss in group 1 was 389 ± 149 cells/mm and in group 2 was 186 ± 63.44 cells/mm (P-value = 0.00134). CONCLUSION: We found a correlation between the speed of stripping, scroll width, and endothelial cell loss. Slow-peeled Descemet membrane endothelial keratoplasty grafts result in a wider scroll width but were associated with a greater reduction in endothelial cell density.
Article
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Importance: Descemet membrane endothelial keratoplasty (DMEK) is a challenging procedure for the surgeon, particularly because of deficient visibility of the delicate tissue due to the natural en face view through the operating microscope. A cross-sectional view would greatly enhance intraoperative overview and enable the surgeon to better control the procedure. Objective: To retrospectively analyze the use of intraoperative optical coherence tomography (iOCT) for improving the safety of DMEK. Design: Intraoperative OCT during DMEK was performed in 26 eyes of 26 patients. We retrospectively analyzed imaging and video data. Setting: Department of Ophthalmology, University of Cologne. Participants: Seven men and 19 women aged 39 to 93 years with corneal endothelial dysfunction undergoing DMEK. Exposure: Descemet membrane endothelial keratoplasty. Main outcomes and measures: Visibility of surgical steps, overall duration of DMEK, overall time for complete intraoperative air filling of the anterior chamber, and correlation between donor age and Descemet rolling behavior. RESULTS Intraoperative OCT enables visualization of all steps of the DMEK procedure. Overall mean (SD) duration of the DMEK procedure was 25.7 (6.9) minutes when using iOCT. Overall mean (SD) complete intraoperative anterior chamber air-filling time was 236 (108) seconds in contrast to 60 to 90 minutes for standard air-filling time. Descemet membrane rolling behavior showed significant inverse correlation between donor age (range, 39-93 years) and the extent of rolling (R2 = 0.5 [P = .006]). Conclusions and relevance: Intraoperative OCT enhances the visibility of graft orientation and unfolding, thereby improving safety of the DMEK procedure. Overall, iOCT is a helpful device that may support surgeons in all steps of DMEK procedures.
Article
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To evaluate the clinical outcome and complications of Descemet membrane endothelial keratoplasty (DMEK), using Descemet-stripping endothelial keratoplasty (DSEK) as a back-up procedure, in the management of Fuchs endothelial dystrophy. Non-randomised prospective clinical study. The first fifty consecutive eyes that underwent DMEK, that is, transplantation of an isolated donor Descemet membrane carrying its endothelium, for Fuchs endothelial dystrophy were evaluated. In all eyes, the best-corrected visual acuity (BCVA) as well as the endothelial cell density (ECD) was measured before and at 6 months after surgery, as clinical outcome parameters. Ten patients required a secondary DSEK for failed DMEK. In the remaining 40 DMEK eyes, 95% had a BCVA of > or = 20/40 (> or = 0.5) and 75% > or = 20/25 (> or = 0.8) at 6 months after surgery. ECD averaged 2618 (+ or - 201) cells/mm(2) before, and 1876 (+ or - 522) cells/mm(2) at 6 months after surgery (n = 35). When the outcomes of DMEK and secondary DSEK procedures were combined, 94% reached a BCVA of > or = 20/40 (> or = 0.5) and 66% > or = 20/25 (> or = 0.8) (n = 47), and ECD averaged 2623 (+ or - 193) cells/mm(2) before, and 1815 (+ or - 578) cells/mm(2) at 6 months after surgery (n = 43). With DSEK as a back-up procedure, DMEK may provide relatively quick and complete visual rehabilitation in a majority of patients operated on for Fuchs endothelial dystrophy. Endothelial cell survival may be similar to earlier types of (lamellar) keratoplasty. Early graft detachment was the main complication in this first series of DMEK surgeries for Fuchs endothelial dystrophy.
Article
Purpose: To quantify endothelial cell loss (ECL) caused by orientation stamps on prestripped and preloaded Descemet membrane endothelial keratoplasty (DMEK) grafts, and to examine a method for reducing ECL using a smaller stamp. Methods: Ten prestripped and 10 preloaded DMEK grafts were prepared with S-stamps. Ten additional preloaded DMEK grafts were prepared with both an S-stamp and a smaller F-stamp in different paracentral areas of the graft. The footprint of each stamp was measured using ink on cardstock. DMEK grafts were stored in viewing chambers filled with 20 mL of Optisol-GS for 3 days at 4°C. ECL was quantified using Calcein-AM staining and FIJI Weka Segmentation. Results: S-stamps on prestripped DMEK grafts contributed an average ECL of 1.1% ± 0.5% (range: 0.6%-2.2%) toward total graft damage, whereas S-stamps on preloaded DMEK grafts contributed approximately twice that amount (average ECL: 2.0% ± 0.7%, range: 1.3%-3.1%, P = 0.004). Overall ECL for prestripped grafts (average: 7.1% ± 3.3%, range: 3.3%-13.7%) and preloaded grafts (average: 11.3% ± 4.2%, range: 6.9%-19.4%) was similar to previous reports. The footprint of the S-stamp was approximately 45% larger than that of the F-stamp. In 10 preloaded grafts marked with both stamps, the S-stamp caused an average ECL of 1.9% ± 0.6% (range: 1.2%-3.2%), whereas the smaller F-stamp caused an average ECL of 1.0% ± 0.2% (range: 0.8%-1.4%, P = 0.0002). Conclusions: Loss of endothelial cells associated with graft-stamping was greater in preloaded tissue than in prestripped tissue and was less with a smaller F-stamp than with a larger S-stamp. Using a smaller stamp could help minimize ECL in prestripped and preloaded DMEK grafts.
Article
Purpose: To report the 3-year assessment of feasibility and usefulness of microscope-integrated intraoperative OCT (iOCT) during ophthalmic surgery. Design: Prospective, consecutive case series. Participants: Adult participants undergoing incisional ophthalmic surgery with iOCT imaging who consented to be enrolled in the Determination of Feasibility of Intraoperative Spectral-Domain Microscope Combined/Integrated OCT Visualization during En Face Retinal and Ophthalmic Surgery (DISCOVER) study. Methods: The DISCOVER study is a single-site, multisurgeon, institutional review board-approved investigational device prospective study. Participants included patients undergoing anterior or posterior segment surgery who underwent iOCT imaging with 1 of 3 prototype microscope-integrated iOCT systems (i.e., Zeiss Rescan 700, Leica EnFocus, or Cole Eye iOCT systems). Clinical characteristics were documented, iOCT was directed by the operating surgeon at predetermined surgical time points, and each surgeon completed a questionnaire after surgery to evaluate the usefulness of iOCT during surgery. Main outcome measures: Feasibility of iOCT based ability to obtain an OCT image during surgery and usefulness of iOCT based on surgeon reporting during surgery. Results: Eight hundred thirty-seven eyes (244 anterior segment cases and 593 posterior segment cases) were enrolled in the DISCOVER study. Intraoperative OCT demonstrated feasibility with successful image acquisition in 820 eyes (98.0%; 95% confidence interval [CI], 96.8%-98.8%). In 106 anterior segment cases (43.4%; 95% CI, 37.1%-49.9%), the surgeons indicated that the iOCT information impacted their surgical decision making and altered the procedure. In posterior segment procedures, surgeons reported that iOCT enabled altered surgical decision making during the procedure in 173 cases (29.2%; 95% CI, 25.5%-33.0%). Conclusions: The DISCOVER iOCT study demonstrated both generalized feasibility and usefulness based on the surgeon-reported impact on surgical decision making. This large-scale study confirmed similar findings from other studies on the potential value and impact of iOCT on ophthalmic surgery.
Article
Purpose: To review the published literature on the safety and outcomes of Descemet membrane endothelial keratoplasty (DMEK) for the surgical treatment of corneal endothelial dysfunction. Methods: Literature searches were last conducted in the PubMed and the Cochrane Library databases most recently in May 2017. The searches, which were limited to English-language abstracts, yielded 1085 articles. The panel reviewed the abstracts, and 47 were determined to be relevant to this assessment. Results: After DMEK surgery, the mean best-corrected visual acuity (BCVA) ranged from 20/21 to 20/31, with follow-up ranging from 5.7 to 68 months. At 6 months, 37.6% to 85% of eyes achieved BCVA of 20/25 or better and 17% to 67% achieved BCVA of 20/20 or better. Mean endothelial cell (EC) loss was 33% (range, 25%-47%) at 6 months. Overall change in spherical equivalent was +0.43 diopters (D; range, -1.17 to +1.2 D), with minimal induced astigmatism of +0.03 D (range, -0.03 to +1.11 D). The most common complication was partial graft detachment requiring air injection (mean, 28.8%; range, 0.2%-76%). Intraocular pressure elevation was the second most common complication (range, 0%-22%) after DMEK, followed by primary graft failure (mean, 1.7%; range, 0%-12.5%), secondary graft failure (mean, 2.2%; range, 0%-6.3%), and immune rejection (mean, 1.9%; range, 0%-5.9%). Overall graft survival rates after DMEK ranged from 92% to 100% at last follow-up. Best-corrected visual acuity after Descemet's stripping endothelial keratoplasty (DSEK) ranged from 20/34 to 20/66 at 9 months. The most common complications after DSEK were graft detachment (mean, 14%; range, 0%-82%), endothelial rejection (mean, 10%; range, 0%-45%), and primary graft failure (mean, 5%; range, 0%-29%). Mean EC loss after DSEK was 37% at 6 months. Conclusions: The evidence reviewed supports DMEK as a safe and effective treatment for endothelial failure. With respect to visual recovery time, visual outcomes, and rejection rates, DMEK seems to be superior to DSEK and to induce less refractive error with similar surgical risks and EC loss compared with DSEK. The rate of air injection and repeat keratoplasty were similar in DMEK and DSEK after the learning curve for DMEK.
Article
Purpose: To assess the relationship between intraoperative unscrolling time of the donor Descemet membrane endothelial keratoplasty (DMEK) tissue and 6-month postoperative endothelial cell loss (ECL), and to determine whether donor age, scroll tightness, and the presence of an S stamp are related to unscrolling time. Methods: Ninety-three consecutive uncomplicated DMEK surgeries performed on eyes with Fuchs endothelial dystrophy using our standardized technique (ie, prestripped tissue with or without a premarked S stamp from our eye bank, overstripping the recipient, Straiko glass injector, no-touch tap technique, and bubble of 20% SF6 gas) were evaluated. Intraoperative unscrolling times and 6-month endothelial cell densities were measured and analyzed. Results: Sixty-nine cases comprised the study cohort. The median unscrolling time was 4 minutes (range: 0.8-17.5 minutes), and the median ECL was 26.9% (range: -4.3% to 80.0%). There was no relationship between unscrolling time and ECL at 6 months by the Pearson correlation coefficient (r = -0.02, P = 0.89). Younger donor age, tighter scrolls, and absence of an S stamp had no correlation with longer unscrolling times (all P > 0.05). Only 2 of 4 cases of iatrogenic primary graft failure had unscrolling times available for analysis; in this limited sample, there was no association between iatrogenic primary graft failure and unscrolling time. Conclusions: Once the DMEK tissue is safely in the anterior chamber, surgeons need not rush the "DMEK dance" because longer unscrolling times may not endanger the endothelium.
Article
Purpose: To present 6-month clinical outcomes from a series of 165 consecutive Descemet membrane endothelial keratoplasty (DMEK) procedures before and after the introduction of a novel stromal-sided S-stamp preparation technique that has decreased the incidence of iatrogenic primary graft failure by eliminating upside-down grafts. Design: Retrospective nonrandomized comparative case series. Participants: We included 165 consecutive eyes that had undergone DMEK surgery for Fuchs' or pseudophakic bullous keratopathy. These cases were divided into 2 cohorts: the first cohort comprised 31 cases that used unstamped tissue before the S-stamp was introduced, and the second cohort comprised 133 cases after the S-stamp was incorporated into the standardized technique. A single unstamped DMEK case was performed after the introduction of the S-stamp for a total of 32 unstamped cases. Methods: Donor materials were prepared at a single eye bank using a standardized technique, which subsequently incorporated the addition of a dry ink gentian violet S-stamp to the stromal side of Descemet membrane. All surgeries were performed at a single clinical site by 5 surgeons (2 attending surgeons and 3 fellows). Two of the 165 DMEK cases were performed for pseudophakic bullous keratopathy (2 cases, 1 in each cohort), and the remaining cases were for Fuchs' endothelial dystrophy. Primary outcome measures were assessed at 6 months and maintained in a prospective institutional review board-approved study. Main outcome measures: We analyzed the 6-month endothelial cell density, incidence of iatrogenic primary graft failure, upside-down graft implantation, and rebubble events. Results: The S-stamp eliminated upside-down graft implantations (0/133 S-stamped vs 3/32 unstamped) and did not significantly alter 6-month endothelial cell loss (31±17% S-stamped vs 29±14% unstamped; P = 0.62) or frequency of rebubble (17/133 S-stamped vs 1/32 unstamped; P = 0.20). Conclusion: The incorporation of a stromal-sided S-stamp eliminates iatrogenic primary graft failure owing to upside-down implantation of DMEK grafts, without adversely affecting early postoperative complications or 6-month endothelial cell loss.
Article
To report endothelial cell loss (ECL) caused by a novel S-stamp preparation technique for Descemet membrane endothelial keratoplasty (DMEK). Six cadaveric human corneas were prepared for DMEK transplantation using a single standardized technique, including the application of a dry ink gentian violet S-stamp to the stromal side of Descemet membrane. Endothelial cell death was evaluated and quantified using computerized analysis of vital dye staining. ECL caused by the S-stamp was 0.6% (range 0.1%-1.0%), which comprised less than one-tenth of the total ECL caused by our preparation of the DMEK graft from the start to finish, including recovery, prestripping, S-stamping, and trephination (13.7% total ECL, range 9.9%-17.6%). Our novel S-stamp donor tissue preparation technique is intuitive to learn and holds the promise of preventing iatrogenic primary graft failure due to upside-down grafts without causing unacceptable increases in ECL.
Article
To investigate the utility of intraoperative optical coherence tomography (OCT) for Descemet Membrane Endothelial Keratoplasty (DMEK) surgery. Prospective consecutive interventional case series. DISCOVER (NCT02423213) is a prospective consecutive interventional case series examining the feasibility and utility microscope-integrated intraoperative OCT in ophthalmic surgery. This report focuses on those eyes in the DISCOVER study undergoing DMEK surgery. The eight cases were the first DMEK cases performed by the primary surgeon (J.M.G.) with microscope integrated intraoperative OCT feedback (Rescan 700, Carl Zeiss Meditec). Qualitative OCT analysis was performed at multiple surgeon-defined time points, including host and donor tissue preparation, graft orientation, graft apposition, and tissue interface fluid dynamics. Correct graft orientation was confirmed by intraoperative OCT prior to unscrolling in 100% of cases. Seven of eight grafts were fully attached at the conclusion of surgery and on postoperative day one. One graft had a linear paracentral fixed area of interface separation corresponding to posterior stromal irregularities which was visible during surgery and unchanged on postoperative day one. Two eyes developed significant peripheral graft dehiscence visible by the first postoperative week. Both grafts were successfully re-attached with repeat gas injection. All eyes demonstrated improvement in best corrected visual acuity and there was a 100% graft survival rate at last follow-up (minimum = 4 months). Surgeon feedback indicated that intraoperative OCT provided valuable information in all eight cases. Real-time intraoperative OCT can provide useful information, which may directly impact surgical decision-making during DMEK surgery. Intraoperative OCT may facilitate the transition for novice DMEK surgeons by increasing surgeon confidence and reducing the risk of iatrogenic graft failure. Copyright © 2015 Elsevier Inc. All rights reserved.
Article
To describe the utility of a new intraoperative optical coherence tomographer (OCT) to evaluate endothelio-Descemet graft orientation during Descemet membrane endothelial keratoplasty (DMEK) procedures. Prospective, observational, and single-center pilot case series including 14 eyes of 14 patients consecutively scheduled for DMEK surgery. After injecting the graft into the anterior chamber, the graft orientation was assessed with the help of anterior segment OCT. The surgical time and unfolding time were measured. The postoperative measurements included best-corrected visual acuity, central pachymetry, and specular microscopy at 1 month. Using the OCT images, it was possible to evaluate the graft orientation in all cases. The mean unfolding time was 6.1 ± 3.0 minutes, the mean best-corrected visual acuity was 0.3 ± 0.3 logarithm of the minimum angle of resolution, the mean decrease in central pachymetry was 213 ± 177 μm, and the mean central endothelial cell count was 1906 ± 319 cells per square millimeter. Live intraoperative OCT is useful to visualize and assess graft orientation in DMEK surgery. It enables faster graft positioning with less graft manipulation in the presence of severe corneal edema.
Article
Importance Descemet membrane endothelial keratoplasty (DMEK) is a challenging procedure for the surgeon, particularly because of deficient visibility of the delicate tissue due to the natural en face view through the operating microscope. A cross-sectional view would greatly enhance intraoperative overview and enable the surgeon to better control the procedure. Objective To retrospectively analyze the use of intraoperative optical coherence tomography (iOCT) for improving the safety of DMEK.Design Intraoperative OCT during DMEK was performed in 26 eyes of 26 patients. We retrospectively analyzed imaging and video data. Setting Department of Ophthalmology, University of Cologne.Participants Seven men and 19 women aged 39 to 93 years with corneal endothelial dysfunction undergoing DMEK.Exposure Descemet membrane endothelial keratoplasty.Main Outcomes and Measures Visibility of surgical steps, overall duration of DMEK, overall time for complete intraoperative air filling of the anterior chamber, and correlation between donor age and Descemet rolling behavior.Results Intraoperative OCT enables visualization of all steps of the DMEK procedure. Overall mean (SD) duration of the DMEK procedure was 25.7 (6.9) minutes when using iOCT. Overall mean (SD) complete intraoperative anterior chamber air-filling time was 236 (108) seconds in contrast to 60 to 90 minutes for standard air-filling time. Descemet membrane rolling behavior showed significant inverse correlation between donor age (range, 39-93 years) and the extent of rolling (R2 = 0.5 [P = .006]).Conclusions and Relevance Intraoperative OCT enhances the visibility of graft orientation and unfolding, thereby improving safety of the DMEK procedure. Overall, iOCT is a helpful device that may support surgeons in all steps of DMEK procedures.
Article
To evaluate visual outcome and endothelial cell survival after Descemet membrane endothelial keratoplasty (DMEK) in comparison with Descemet stripping automated endothelial keratoplasty (DSAEK). Single-center, retrospective, consecutive case series. Thirty-eight eyes of 38 consecutive patients undergoing DMEK, who completed a 6-month follow-up, were compared with 35 eyes of 35 consecutive patients undergoing DSAEK for Fuchs endothelial dystrophy or pseudophakic bullous keratopathy. Main outcome measures included best-corrected visual acuity (in logarithm of the minimal angle of resolution [logMAR] units) and endothelial cell density within a 6-month follow-up. Best-corrected visual acuity increased from 0.70 ± 0.48 logMAR and 0.75 ± 0.32 logMAR before surgery to 0.21 ± 0.14 logMAR and 0.48 ± 0.19 logMAR 3 months after DMEK and DSAEK (P < .001), respectively, and to 0.17 ± 0.12 logMAR and 0.36 ± 0.15 logMAR 6 months after DMEK and DSAEK (P < .001), respectively. Endothelial cell density decreased from 2575 ± 260 cells/mm(2) and 2502 ± 220 cells/mm(2) before surgery to 1498 ± 244 cells/mm(2) and 1778 ± 420 cells/mm(2) 3 months after DMEK and DSAEK (P < .001), respectively, and to 1520 ± 299 cells/mm(2) and 1532 ± 495 cells/mm(2) 6 months after DMEK and DSAEK (P = .483), respectively. Central corneal thickness decreased from 652 ± 92 μm before surgery to 517 ± 45 μm 6 months after DMEK, and from 698 ± 137 μm before surgery to 618 ± 66 μm 6 months after DSAEK. DMEK provided faster and more complete visual rehabilitation when compared with DSAEK. However, there were no significant differences concerning endothelial cell survival within a 6-month follow-up.
Article
To evaluate the relative risk of immunologic rejection episode in patients who underwent Descemet's membrane endothelial keratoplasty (DMEK), Descemet's stripping endothelial keratoplasty (DSEK), and penetrating keratoplasty (PK). Comparative case series. One hundred forty-one eyes treated with DMEK at Price Vision Group, Indianapolis, Indiana. The patients in the DMEK group were compared retrospectively with cohorts of DSEK (n = 598) and PK (n = 30) patients treated at the same center, with similar demographics, follow-up duration, and indications for surgery. The postoperative steroid regimen and rejection criteria were identical in the 3 groups. Kaplan-Meier survival analysis, which takes varying length of follow-up into consideration, was performed to determine the cumulative probability of a rejection episode 1 and 2 years after surgery. Proportional hazards analysis was used to determine the relative risk of rejection episodes between the 3 groups. P<0.05 was considered significant and calculated using the log-rank test. Rejection-free survival and cumulative probability of a rejection episode. The mean recipient age was 66 years (56% females and 94% Caucasian) and median follow-up duration was 13 months (range, 3-40) in the DMEK group. Fuchs' dystrophy was the most common indication for surgery (n = 127; 90%) followed by pseudophakic bullous keratopathy (n = 4; 4%) and regrafts (n = 9; 6.4%). Only 1 patient (0.7%) had a documented rejection episode in the DMEK group compared with 54 (9%) in the DSEK and 5 (17%) in the PK group. The Kaplan-Meier cumulative probability of a rejection episode at 1 and 2 years was 1% and 1%, respectively, for DMEK; 8% and 12%, respectively, for DSEK; and 14% and 18%, respectively, for PK. This was a highly significant difference (P = 0.004). The DMEK eyes had a 15 times lesser risk of experiencing a rejection episode than DSEK eyes (95% confidence limit [CL], 2.0-111; P = 0.008) and 20 times lower risk than PK eyes (95% CL, 2.4-166; P = 0.006). Patients undergoing DMEK had a significantly reduced risk of experiencing a rejection episode within 2 years after surgery compared with DSEK and PK performed for similar indications using the same corticosteroid regimen.
Article
Descemet membrane endothelial keratoplasty is a new technique for the replacement of diseased corneal endothelium with healthy donor endothelium. During this procedure, manipulation of the donor endothelium-Descemet membrane layer within the recipient anterior chamber can be associated with loss of the correct anterior-posterior orientation. Herein, we describe a simple method to keep the correct donor orientation during transplantation by marking the edge of the endothelium-Descemet membrane layer. Interventional case series. Donor discs were created by stripping of the endothelium-Descemet membrane layer from corneoscleral buttons. Before completion of stripping, 3 circular marks were set in an identifiable order at the edge of the donor disc. After removal of the recipient Descemet membrane, the donor graft was inserted into the anterior chamber, unfolded, and attached to the posterior corneal stroma with an air bubble. Correct anterior-posterior orientation of the graft was identified by the clockwise order of the 3 marks. The marks allowed identification of the anterior-posterior orientation of the endothelium-Descemet membrane layer after unfolding in the anterior chamber and attachment to the recipient stroma in all cases. In 4 of 25 patients, orientation was upside down after unfolding of the roll, requiring inversion of the refolded donor graft. Marking the edges of the endothelium-Descemet membrane layer helps to keep the correct orientation without adverse effects on donor detachment or corneal clarity during and after Descemet membrane endothelial keratoplasty.
Article
To describe Descemet's membrane endothelial keratoplasty (DMEK) techniques, perioperative challenges, management, and visual and refractive outcomes. Prospective, multicenter, consecutive case series. Sixty eyes of 56 patients with Fuchs' endothelial dystrophy, pseudophakic bullous keratopathy, or failed previous graft. Descemet's membrane (DM) and endothelium were stripped from donor corneas submerged in corneal storage solution in a corneal viewing chamber. Donor DM diameters were 8.5 or 9.0 mm. The central 7 mm of DM was stripped from the recipient cornea. After staining with trypan blue to improve visualization, donor DM was inserted through a 2.8-mm incision. Descemet's membrane endothelial keratoplasty was performed alone (n = 48) or was combined with phacoemulsification and lens implantation (n = 11), pars plana vitrectomy (n = 2), or both. Best spectacle-corrected visual acuity (BSCVA), manifest refraction, and endothelial cell density. Median BSCVA was 20/30 at 1 month (range, 20/20-20/60), improving from 20/50 (range, 20/25-hand movements) before DMEK, excluding 4 eyes (7%) with preexisting ocular pathologic features that limited visual potential. At 3 months, 26% had 20/20 vision, 63% saw 20/25 or better, and 94% saw 20/40 or better. Refractive cylinder remained unchanged at 0.9 diopters (D; P = 0.93), and a hyperopic shift of 0.49+/-0.63 D (P = 0.0091) was noted in DMEK single procedures. Endothelial cell loss was 30%+/-20% at 3 months and 32%+/-20% in 38 eyes that reached the 6-month examination. Median pachymetry decreased from 660 mum before surgery to 530 mum. Descemet's membrane stripped successfully from 60 of 72 donor corneas; 6 were converted successfully to Descemet's stripping automated endothelial keratoplasty (DSAEK) and 6 (8%) were discarded. Only 1 graft detached completely, but air was reinjected in 38 eyes (63%), mainly for partial detachments. Five DMEK corneas (8%) failed to clear and were replaced successfully with DMEK or DSAEK. All remained clear at last follow-up. Compared with DSAEK, DMEK provided a significantly higher rate of 20/20 and 20/25 vision, with comparable endothelial cell loss. Descemet's membrane endothelial keratoplasty restored physiologic pachymetry, but donor preparation and attachment currently are more challenging than with DSAEK.
Article
To describe Descemet membrane endothelial keratoplasty (DMEK) with organ cultured Descemet membrane (DM) in a human cadaver eye model and a patient with Fuchs endothelial dystrophy. In 10 human cadaver eyes and 1 patient eye, a 3.5-mm clear corneal tunnel incision was made. The anterior chamber was filled with air, and the DM was stripped off from the posterior stroma. From organ-cultured donor corneo-scleral rims, 9.0-mm-diameter "DM rolls" were harvested. Each donor DM roll was inserted into a recipient anterior chamber, positioned onto the posterior stroma, and kept in position by completely filling the anterior chamber with air for 30 minutes. In all recipient eyes, the donor DM maintained its position after a 30-minute air-fill of the anterior chamber followed by an air-liquid exchange. In the patient's eye, 1 week after transplantation, best-corrected visual acuity was 1.0 (20/20) with the patient's preoperative refraction, and the endothelial cell density averaged 2350 cells/mm. DMEK may provide quick visual rehabilitation in the treatment of corneal endothelial disorders by transplantation of an organ-cultured DM transplanted through a clear corneal tunnel incision. DMEK may be a highly accessible procedure to corneal surgeons, because donor DM sheets can be prepared from preserved corneo-scleral rims.