Techniques for Learning Descemet Membrane Endothelial Keratoplasty for Eyes of Asian Patients With Shallow Anterior Chamber

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Descemet Membrane Endothelial Keratoplasty (DMEK) Anesthesia Analysis

PURPOSE

Comparison of safety and clinical results of Descemet membrane endothelial keratoplasty (DMEK) in topical, peribulbar, or general anesthesia.

METHODS

Retrospective, post hoc matched study of 346 patients who received DMEK surgery with different types of anesthesia (n = 54 topical, n = 137 peribulbar, n = 155 general anesthesia). Outcome criteria were intraoperative complications, endothelial cell count (ECC), central corneal thickness (CCT) and graft rejection rate, rebubbling rate, and visual acuity (VA). Mean follow-up time was 9.4 ± 2.8 months.

RESULTS

The group with topical anesthesia showed intraoperative difficulties such as vitreous pressure (p = 0.01) and difficult graft unfolding (p = 0.4), possibly leading to a higher rebubbling rate (p = 0.03) and therefore graft failure (p = 0.39). However, rebubbling and graft failure occurred more often when the graft preparation was more difficult (p = 0.2, p = 0.13, respectively), which was independent of anesthesia. All three groups achieved comparable functional results regarding VA, ECC, and CCT after 6 months.

CONCLUSION

DMEK under topical anesthesia is feasible and shows comparable final visual outcomes but should be limited to selected cooperative patients and performed by experienced surgeons due to the potential for increased intraoperative challenges.

Clinical Outcomes of Descemet Membrane Endothelial Keratoplasty Using a Preloaded Imported Graft

PURPOSE

Although the popularity of Descemet membrane endothelial keratoplasty (DMEK) is increased, there is still few clinical studies in Korea. In this study, we aimed to report the initial clinical outcomes of DMEK in patients followed up for more than 6 months.

METHODS

A total of 96 eyes that underwent DMEK by a single surgeon for Fuchs endothelial corneal dystrophy, pseudophakic bullous keratopathy, or other indications were evaluated for best-corrected visual acuity (BCVA), endothelial cell density (ECD), central corneal thickness (CCT), postoperative complications, and graft survival.

RESULTS

The postoperative BCVA significantly increased compared to the preoperative BCVA by 59.4% (1.00 ± 0.77 logarithm of the minimum angle of resolution vs. 0.67 ± 0.76 logarithm of the minimum angle of resolution, p < 0.001). The average preoperative ECD was 754 ± 382 cells/mm2, increasing to 1,333 ± 562 cells/mm2 at 3 months (76.8%, p < 0.001), 1,334 ± 632 cells/mm2 at 6 months (76.9%, p < 0.001), 1,121 ± 474 cells/mm2 at 12 months (48.7%, p = 0.024), and 972 ± 458 cells/mm2 at 24 months postoperatively (28.9%, p = 0.445). Compared to 3 months, the ECD declined by 15.9% at 12 months (p = 0.009) and 27.1% at 24 months postoperatively (p = 0.158). The average CCT was 675 ± 113 μm preoperatively, decreasing to 581 ± 102, 574 ± 101, and 594 ± 94 μm at 6, 12, and 24 months after DMEK, respectively (p < 0.001 between all follow-up time points). Allograft rejection was detected in three (3.1%) and 14 eyes (14.6%) underwent retransplantation at an average of 10.1 ± 8.4 months after DMEK.

CONCLUSIONS

DMEK is promising for maintaining corneal clarity, low postoperative complication rates, and stable graft longevity.

The effect of anterior segment parameters on surgical success of Descemet membrane endothelial keratoplasty: a prospective study

PURPOSE

To investigate how anterior segment parameters affect the success of Descemet membrane endothelial keratoplasty (DMEK) in patients with endothelial insufficiency without stromal opacities and to identify factors predisposing them to repeat keratoplasty.

METHODS

Our prospective observational study included patients who underwent primary DMEK for Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy between March 2019 and March 2020. After a detailed ophthalmologic examination, corneal topographic analysis, anterior segment optical coherence tomography (AS-OCT) scans, endothelial cell density (ECD) and axial length (AL) measurements were performed. Surgical success was defined as no endothelial dysfunction during follow-up. Changes in the parameters and how preoperative parameters affect surgical success were investigated.

RESULTS

In 43 eyes of 43 patients (mean age: 68.58 ± 8.51 years), mean visual acuity was 1.73 ± 0.74 LogMAR before DMEK and 0.31 ± 0.29 LogMAR in the final visit. Central corneal thickness (CCT, p = 0.026) and mean anterior chamber depth (ACD, p = 0.001) affected surgical success. Preoperative CCT values greater than 770 µm increased the risk of repeat keratoplasty by 8.75-fold, whereas preoperative ACD values less than 2.5 mm increased the risk by 2.92-fold.

CONCLUSION

Preoperative higher CCT and lower ACD values were associated with surgical failure after DMEK. Early surgery may be considered for more successful results.

TRIAL REGISTRATION

This prospective study has been registered on the ClinicalTrials.gov system with the registration number NCT04420429 on 06/06/2020.

Descemet membrane endothelial keratoplasty: Update on preoperative considerations, surgical techniques, and outcomes

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.

Graft Size and Double Scroll Formation Rate in Descemet Membrane Endothelial Keratoplasty

PURPOSE

This study aimed to evaluate the usefulness of intentional double scroll formation of donor Descemet membrane (DM) inside a glass tube inserter (the Fogla technique) in DM endothelial keratoplasty (DMEK) for controlled insertion and unfolding of grafts.

METHODS

Eleven consecutive patients who underwent DMEK were included in this study. We sought to specify graft characteristics in which double scroll configuration was successfully formed using the Fogla technique. We compared donor age, graft size, surgical time, unfolding time, and visual outcomes between patients with and without double scroll configuration. The ability to form double scroll formation of DM grafts of various diameters and unfolding time of DM grafts was evaluated using total seven eye-bank eyes in ex vivo experiments.

RESULTS

A double scroll configuration inside a glass tube was successfully obtained in six DMEK grafts (54.5%). When comparing clinical features between those with and without double scroll configuration, only graft size was significantly larger in those with double scroll configuration (7.9 ± 0.2 mm) than in those without (7.4 ± 0.4, P = 0.03). There were no significant differences in other features and clinical outcomes, although unfolding-time was shorter in eyes with double scroll configuration (4.6 ± 2.0 min) compared to those without (8.6 ± 8.1, P = 0.21). Ex vivo experiments showed that unfolding time was significantly shorter in double scroll configuration (2.71 ± 0.49 min) than in single scroll (5.02 ± 0.79, P = 0.01).

CONCLUSIONS

A double scroll configuration within a glass tube can be obtained more frequently in larger DMEK grafts (8.0 mm in diameter), which may result in easier and faster DMEK procedures.

Clinical outcome of Descemet membrane endothelial keratoplasty (DMEK) with imported donor corneas in eyes of Asian patients; endothelium-in versus endothelium-out method

Objective

We investigated whether (1) imported pre-cut tissue is feasible for Descemet membrane endothelial keratoplasty (DMEK) in eyes of Asian patients, (2) the clinical outcome is comparable between the endothelium‐in and endothelium‐out methods, and (3) the corneal edema-induced anterior curvature changes may have an effect on the refractive error.

Methods

The medical records of 32 DMEK patients who underwent either the endothelium-out or endothelium-in method using imported pre-cut grafts with a 3-day pre-cut-to-use time were retrospectively analyzed. Fuchs’ endothelial dystrophy (37.5%) and bullous keratopathy (62.5%) cases were included. The main clinical outcome measures were graft survival, best corrected visual acuity (BCVA), endothelial cell density (ECD), corneal thickness (CT), and complications. Correlation of the anterior curvature changes with refractive error was analyzed in the DMEK with cataract surgery group.

Results

The overall survival rate was 71.9%. Final graft failures were caused by rejection, glaucoma, and infection. Visual acuities improved by 89.3%. BCVA better than 20/40 and 20/20 was found in 75% and 28.6% of patients, respectively. The ECDs at 3 months and 1 year were 1400 and 1083 cells/mm², respectively. The mean survival time, ECD, BCVA, CT, and complication rates were not different between the endothelium-in and endothelium-out methods. A hyperopic shift by +0.42 D was not related to the anterior curvature changes.

Conclusion

Imported pre-cut tissues with a ≤ 3-day pre-cut-to-use time are feasible for DMEK in the treatment of corneal endothelial edema in eyes of Asian patients, and both endothelium-in and endothelium-out methods appear to be comparatively effective. Edema-induced anterior curvature change may not affect the refractive shift.

Severe Corneal Edema Increases ECL From Grafts After DSAEK-Corneal Edema and ECL After DSAEK

OBJECTIVES

To determine the relationship between the preoperative degree of corneal edema in the recipient and the endothelial cell density in grafts after Descemet stripping automated endothelial keratoplasty (DSAEK).

METHODS

This retrospective case series enrolled 111 eyes of 107 patients who underwent DSAEK. The preoperative and postoperative central corneal thickness (CCT) was measured by anterior-segment optical coherence tomography. Eyes were divided into three groups according to the preoperative recipient CCT: group A (mild edema): 550 μm

RESULTS

The recipient CCT (all groups combined) was 805.99±132.70 μm preoperatively and decreased to 656.31±105.02 μm at 1 month, decreased to 626.08±81.40 μm at 6 months, and remained stable between 12 (P=0.144) and 24 months (P=0.485) postoperatively. The mean ECL was 27.34±15.43%, 33.56±17.13%, 39.18±16.71%, and 45.87±14.27% at 1, 6, 12, and 24 months, respectively. The percentage of ECL in group C was higher than that in the other 2 groups through the 24-month follow-up. The difference in ECL between groups A and C was significant at 24 months (group A: 42.45±14.47%; group C: 52.49±10.65%; P=0.019).

CONCLUSIONS

The degree of corneal edema in the recipient was associated with implant ECL. Compared with mild and moderate corneal edema, the severe corneal edema may cause greater ECL after DSAEK.

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Key Words

• dsaek
• endothelial cell loss
• degree of corneal edema

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MESH Headings

• Corneal Diseases/etiology
• Corneal Diseases/surgery
• Corneal Edema/etiology
• Corneal Edema/surgery
• Descemet Stripping Endothelial Keratoplasty/adverse effects
• Descemet Stripping Endothelial Keratoplasty/methods
• Endothelial Cells
• Endothelium, Corneal/transplantation
• Humans
• Retrospective Studies

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Affiliation(s)

Shaofeng Gu Department of Ophthalmology (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China; and Beijing Key Laboratory of Restoration of Damaged Ocular Nerve (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China.
Rongmei Peng Department of Ophthalmology (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China; and Beijing Key Laboratory of Restoration of Damaged Ocular Nerve (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China.
Gege Xiao Department of Ophthalmology (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China; and Beijing Key Laboratory of Restoration of Damaged Ocular Nerve (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China.
Jing Hong Department of Ophthalmology (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China; and Beijing Key Laboratory of Restoration of Damaged Ocular Nerve (S.G., R.P., G.X., J.H.), Peking University Third Hospital, Beijing, China.

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

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

Trends in surgical procedures and indications for corneal transplantation over 27 years in a tertiary hospital in Japan

PURPOSE

To characterize trends in procedures, and indications for corneal transplantation over 27 years in a single referral center in Japan.

STUDY DESIGN

Retrospective study.

METHODS

Data from a consecutive series of corneal transplant surgery cases performed from 1991 to 2017at Ichikawa General Hospital were collected. The surgical procedures, indications, and causes of corneal endothelial dysfunction were evaluated.

RESULTS

Among 6,025 transplantations, a total of 3,991 cases underwent penetrating keratoplasty (PKP), 1009 underwent (deep) anterior lamellar keratoplasty, 746 underwent endothelial keratoplasty, and 309 underwent epithelial transplantation. Over that period the frequency of PKP decreased, whereas the frequency of lamellar keratoplasty increased. The four major surgical indications were bullous keratoplasty (BK 30.0%), regraft (24.2%), post-keratitis scars (17.1%), and keratoconus (11.4%). After dividing the study period into four time periods, we found that BK and regraft increased (from 20.3% to 34.5% and 18.2% to 31.1%, respectively), whereas post-keratitis scars and keratoconus decreased (from 26.0% to 9.5% and 14.1% to 7.2%, respectively) between the first and last period. Pseudophakic or aphakic BK were the major causes of corneal endothelial dysfunction until 2010. Cases of laser-iridotomy-induced BK peaked in 35 eyes (34.3% of BK) in 2000 and declined after 2013. Cases of Fuchs endothelial corneal dystrophy increased from 0 in 1991, to 15 eyes (18.5% of BK) in 2017.

CONCLUSION

Lamellar keratoplasty has replaced PKP in our hospital. BK and regraft have increased, whereas post-keratitis scars and keratoconus have decreased. Laser-iridotomy-induced BK has decreased during the past decade, whereas Fuchs endothelial corneal dystrophy has increased.

Outcomes of Descemet Membrane Endothelial Keratoplasty in Bangkok, Thailand

Purpose

To investigate the medium-term clinical outcomes and risk factors for primary graft failure after Descemet membrane endothelial keratoplasty (DMEK) in Thai patients.

Patients and Methods

This is a single-center retrospective cohort study. Sixty-two eyes of 62 patients who underwent DMEK at Ramathibodi Hospital, Bangkok, Thailand, with a minimum of 24-month follow-up were recruited. Preoperative donor and recipient characteristics, intraoperative data, and postoperative outcomes including best-corrected visual acuity (BCVA), graft clarity, endothelial cell density (ECD), central corneal thickness (CCT), and complications were evaluated at 1, 3, 6, 12, and 24 months after surgery.

Results

The mean age of the patients was 67.2 ± 9.9 years, and 52% were female. The mean follow-up time was 37.5 ± 11.0 months. The most common indications for DMEK were Fuchs' endothelial corneal dystrophy (FECD) (53.2%) and pseudophakic bullous keratopathy (PBK) (17.7%). Nearly half of patients had triple-DMEK. The median preoperative BCVA was 20/400. Postoperative BCVA of ≥ 20/40 was reached in 37.1% and of ≥ 20/20 in 6.5% after 1 month which increased to 54.8% and 17.7% after 3 months; and to 67.7% and 27.4% after 24 months. Endothelial cell loss (ECL) at 3, 6, 12, and 24 months was 30.5%, 33.8%, 44.4%, and 45.9%, respectively. Graft diameter was the single factor, showing a significant relationship with postoperative ECD. Most frequent postoperative complications included graft detachment (22.6%), increased IOP/glaucoma (17.7%), and primary graft failure (16.1%). In univariate analysis, death-to-operation time and the diagnosis of PBK were significantly associated with the occurrence of primary graft failure.

Conclusion

DMEK is a safe, effective, and feasible treatment for endothelial failure in Asian eyes. Careful case selection, use of relatively fresh donor tissues, and appropriate surgical techniques can prevent primary graft failure and facilitate optimal outcomes following surgery.

Descemet Membrane Endothelial Keratoplasty in Asian Eyes: Intraoperative and Postoperative Complications

PURPOSE

To describe intraoperative and postoperative complications of Descemet membrane endothelial keratoplasty (DMEK) in Asian eyes.

METHODS

A: prospective comparative study of consecutive cases of DMEK cases between January 2016 and January 2018. A subgroup of consecutive patients were optimized with preoperative topical eye drops and modification of donor insertion. Main outcome measures were intraoperative complications and total surgical time. Secondary outcome measures were postoperative complications and endothelial cell loss (ECL) at the 6-month follow-up.

RESULTS

We included 50 consecutive patients in this study; mean age of 66 ± 9 years old with 70% women. The indications for DMEK were Fuchs endothelial dystrophy (82%) and bullous keratopathy (18%). When compared with the standard group (n = 24 eyes), the optimized DMEK group (n = 26 eyes) was associated with a significantly reduced surgical time (33.9 ± 12.7 vs. 26.9 ± 7.6 minutes; P = 0.041), lower ECL at 6 months (27.2 ± 17.1% vs. 13.7 ± 9.7%; P = 0.012) and lower risk of high vitreous pressure causing iris prolapse (16.7% vs. 0%; P = 0.046). Multivariate analysis revealed a shorter surgical time (Odds Ratio [OR]: 0.924; 95% confidence interval: 0.858-0.995; P = 0.036) and reduced ECL (OR: 0.907; 95% confidence interval: 0.843-0.977; P = 0.01) in the optimized group.

CONCLUSIONS

We observed intraoperative challenges such as difficulty with donor insertion with increased vitreous pressure in Asian eyes by performing DMEK surgery, which may be reduced with anticipated preoperative and postoperative measures.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Graft detachments in endothelial keratoplasty

Graft detachment is the most common complication of endothelial keratoplasty. With the ongoing advancements in the field of endothelial keratoplasty, our understanding of risk factors of graft detachments and its management has been evolving. Various prevention measures have been described in literature including presoaking the donor graft, anterior chamber tamponade, venting incisions, sutures to prevent dislocation of graft. Management of a detached graft involves secondary interventions such as rebubbling, suturing and regrafts. In this review, we discuss graft detachment in different types of endothelial keratoplasty techniques including Descemet stripping endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty and Descemet's membrane endothelial keratoplasty; with emphasis on incidence, risk factors, preventive measures and their management.

Iris Posterior Synechiae After Descemet Membrane Endothelial Keratoplasty in Asian Eyes: Prevention and Management of Posterior Synechiae

OBJECTIVES

To evaluate the efficacy of a mydriatic agent for posterior synechiae after phacoemulsification and intraocular lens (IOL) implantation followed by Descemet membrane endothelial keratoplasty (staged DMEK).

METHODS

In this prospective study, the outcomes of DMEK with or without mydriasis (0.5% tropicamide and 0.5% phenylephrine hydrochloride [Mydrin-P; Santen, Osaka, Japan]) after the DMEK procedure were analyzed. Patients underwent IOL implantation approximately 4 weeks before DMEK. Six months after DMEK, the iris posterior synechiae severity score was evaluated based on the extent of posterior synechiae affecting the eight areas (45° each) of the pupillary rim (posterior synechiae score; grades 0-8). Best spectacle-corrected visual acuity, central corneal thickness, endothelial cell density, axial length, and the amount of air at the end of the surgery were also evaluated.

RESULTS

Fifteen eyes of 15 patients (mydriatic: n=8, control: n=7) were eligible for inclusion. Iris posterior synechiae were detected in all seven eyes (100.0%) in the control group, whereas they were noted in two eyes in the mydriatic group (25%). The mean iris posterior synechiae score was 0.69±1.20 in the mydriatic group and was significantly lower than that in the control group (4.57±0.90; P<0.001). There was no significant difference in other clinical factors. Although the incidence and scores of posterior synechiae in the control group were higher, the incidence was significantly reduced with the use of a mydriatic agent (in the mydriatic group).

CONCLUSIONS

Use of a mydriatic agent is an effective measure to prevent postoperative synechiae after DMEK.

A Deep Learning Approach in Rebubbling After Descemet's Membrane Endothelial Keratoplasty

PURPOSE

To evaluate the efficacy of deep learning in judging the need for rebubbling after Descemet's endothelial membrane keratoplasty (DMEK).

METHODS

This retrospective study included eyes that underwent rebubbling after DMEK (rebubbling group: RB group) and the same number of eyes that did not require rebubbling (non-RB group), based on medical records. To classify the RB group, randomly selected images from anterior segment optical coherence tomography at postoperative day 5 were evaluated by corneal specialists. The criterion for rebubbling was the condition where graft detachment reached the central 4.0-mm pupil area. We trained nine types of deep neural network structures (VGG16, VGG19, ResNet50, InceptionV3, InceptionResNetV2, Xception, DenseNet121, DenseNet169, and DenseNet201) and built nine models. Using each model, we tested the validation data and evaluated the model.

RESULTS

This study included 496 images (31 eyes from 24 patients) in the RB group and 496 images (31 eyes from 29 patients) in the non-RB group. Because 16 picture images were obtained from the same point of each eye, a total of 992 images were obtained. The VGG19 model was found to have the highest area under the receiver operating characteristic curve (AUC) of all models. The AUC, sensitivity, and specificity of the VGG19 model were 0.964, 0.967, and 0.915, respectively, whereas those of the best ensemble model were 0.956, 0.913, and 0.921, respectively.

CONCLUSIONS

This automated system that enables the physician to be aware of the requirement of RB might be clinically useful.

Anatomical Changes in the Anterior Chamber Volume After Descemet Membrane Endothelial Keratoplasty

PURPOSE

To evaluate changes in the anterior chamber of eyes that have undergone Descemet membrane endothelial keratoplasty (DMEK) and to identify factors that affect these changes.

METHODS

This retrospective study included 25 pseudophakic eyes of 25 patients who underwent DMEK. We determined the preoperative and postoperative values of the best spectacle-corrected visual acuity, spherical equivalent (SE), anterior chamber volume (ACV), anterior chamber depth (ACD), central corneal thickness (CCT), and scleral spur angle (SSA) evaluated using anterior segment optical coherence tomography and iris damage score and iris posterior synechiae score. We defined ∆ as the average change rate from the preoperative to postoperative value for each factor at 1 month (SE at 6-12 months) postoperatively. We also analyzed correlations between ∆ACV, ∆SE, and other preexisting factors.

RESULTS

Compared with the preoperative ACV value (128 ± 28 mm3), the postoperative value significantly increased to 155 ± 21 mm3 (P < 0.001); ∆SE was +1.01 ± 1.09 diopters. ∆ACV was negatively correlated with preoperative ACD (R = 0.643, P < 0.001) and SSA (R = 0.555, P = 0.001) and positively correlated with ∆ACD (R = 0.799, P < 0.001) and ∆SSA (R = 0.608, P < 0.001). ∆CCT, iris damage score, and iris posterior synechiae score were not significantly correlated with ∆ACV. ∆SE was positively correlated with ∆ACV, ∆ACD, and ∆SSA (R = 0.680, 0.455, and 0.478; P < 0.001, <0.05, and <0.05, respectively).

CONCLUSIONS

An increase in the ACV and hyperopic change was noted after successful DMEK, especially in eyes with narrow-angled shallow anterior chambers.

Analysis of different types of anesthesia in descemet membrane endothelial keratoplasty

PURPOSE

The purpose of this study is to compare the safety and clinical results of descemet membrane endothelial keratoplasty (DMEK) in topical, peribulbar or general anesthesia.

METHODS

This is a retrospective, post hoc matched study of 120 patients having received DMEK surgery with different types of anesthesia (n = 40 topical, n = 40 peribulbar, n = 40 general anesthesia). Endpoint criteria were intraoperative complications, endothelial cell count, central corneal thickness and graft rejection rate, rebubbling rate and best-corrected visual acuity after 1, 3 and 6 months.

RESULTS

The group with topical anesthesia showed more often intraoperative difficulties such as vitreous pressure (p < 0.05), difficult graft unfolding (p = 0.14) and patient restlessness (p = 0.07). However, all three groups achieved comparable functional visual results after 6 months (p = 0.96).

CONCLUSION

DMEK in topical anesthesia is feasible and shows comparable final visual results but should be restricted to selected cooperative patients and performed by experienced surgeons due to possible higher intraoperative challenges.

Risk Factors for Cystoid Macular Edema After Descemet Membrane Endothelial Keratoplasty

PURPOSE

To investigate factors associated with cystoid macular edema (CME) after Descemet membrane endothelial keratoplasty (DMEK) in Asian eyes.

METHODS

In this retrospective, interventional, consecutive case series, 77 eyes of 65 patients who underwent DMEK were evaluated; in 53 eyes, cataract surgery was performed 1 month before DMEK (staged DMEK), and 24 eyes underwent DMEK alone (simple DMEK). Central retinal thickness, incidence of CME, postoperative best-corrected visual acuity, central corneal thickness, and corneal endothelial cell density were assessed at 1, 3, and 6 months after surgery. Multiple regression analysis and stepwise variable selection were performed for parameters such as type of surgery, iris damage scores, age, sex, axial length, preoperative visual acuity, rebubbling, air volume in the anterior chamber on postoperative day 1, history of diabetes, and endothelial cell density loss rates at 6 months after surgery.

RESULTS

CME occurred in 12 (15.6%) of 77 eyes. There was no significant difference in best-corrected visual acuity between eyes with and without CME (P = 0.27). Multivariable analysis revealed that the difference in iris damage scores between before and after DMEK (P < 0.001), air volume in the anterior chamber (P = 0.012), simple DMEK (P = 0.020), and rebubbling (P = 0.036) were significantly associated with CME. Stepwise variable selection indicated that iris damage (P < 0.001) was the most important risk factor for CME.

CONCLUSIONS

Iris damage due to DMEK might be a possible risk and aggravating factor for the development of CME after DMEK. Surgeons should attempt to minimize damage to the iris.

Descemet's membrane endothelial keratoplasty for pseudoexfoliation syndrome: a case series

Background

To evaluate the clinical outcomes and features of Descemet’s membrane endothelial keratoplasty (DMEK) for eyes with pseudoexfoliation syndrome (PEX).

Methods

In this retrospective study, 37 DMEK cases were reviewed from available medical records. Patients who exhibited endothelial dysfunction derived from PEX or Fuchs endothelial corneal dystrophy (FECD) and successfully underwent cataract surgery about four weeks before DMEK were enrolled. The best spectacle-corrected visual acuity (BSCVA), central corneal thickness (CCT), endothelial cell density (ECD), and incidence of intra-operative/post-operative complications of DMEK were analyzed.

Results

This study included 14 eyes of 14 patients (PEX: n = 6, FECD: n = 8). There was no primary graft failure. In the PEX group, BSCVA improved from 0.67 ± 0.28 at the preoperative point to 0.43 ± 0.14 at 1 month, 0.27 ± 0.10 at 3 months, and 0.19 ± 0.08 at 6 months after DMEK. The donor corneal ECD was 2704 ± 225 cells/mm² at the preoperative point and decreased to 1691 ± 498 cells/mm² at 1 month, 1425 ± 366 cells/mm² at 3 months, and 1281 ± 340 cells/mm² (52.7 ± 11.7% less than ECD of the donor graft) at 6 months after DMEK. None of the patients required rebubbling. When compared with the FECD group, no statistical difference was observed in CCT (p = 0.821); BSCVA (p = 0.001) and the reduction rate of ECD (p = 0.010) were relatively worse.

Conclusions

DMEK is effective for the treatment of endothelial dysfunction due to PEX.

Electronic supplementary material

The online version of this article (10.1186/s12886-019-1130-1) contains supplementary material, which is available to authorized users.

Visual Outcome of Descemet Membrane Endothelial Keratoplasty during the Learning Curve in Initial Fifty Cases

This study was performed to evaluate the clinical outcomes of the first fifty patients who underwent Descemet membrane endothelial keratoplasty (DMEK) during the 3-month postoperative period and to describe the challenges encountered during the learning curve. In this retrospective study, we reviewed the charts of patients who underwent DMEK. All information regarding patient demographics, indication for surgery, preoperative and postoperative visual acuity at 3 months, donor age, and complications encountered intraoperatively and postoperatively was recorded. Donor endothelial cell count at the time of surgery and during the 3-month follow-up was noted. Data were analyzed using SPSS version 17. Fifty eyes of 49 patients were included in the study with majority being female patients (male : female = 2 : 3). Mean age of patients was 56.8 ± 11.4 years with the age range of 22–78 years. The common indications for DMEK were pseudophakic bullous keratopathy –57.1%, Fuchs endothelial dystrophy-34.7%, failed grafts-6.1% (Descemet stripping endothelial keratoplasty (DSEK) and failed penetrating keratoplasty), and others. Preoperative best spectacle-corrected visual acuity was <20/400 in 88% cases. Postoperative best spectacle-corrected visual acuity at 3 months was >20/63 in 41.8% of the cases, and 93% had visual acuity of 20/200 or better. Donor size was 8 mm, and average donor endothelial cell count (ECC) was 2919 ± 253 cells/mm². Average ECC at 3 months postoperatively was 1750 ± 664 cells/mm², which showed a 40% decrease in ECC. The most common encountered complication was graft detachment, which occurred in 16% cases for which rebubbling was done. Regular follow-up and timely identification of graft detachment may prevent the need for retransplantation.

Evaluation of Patent Blue as the Vital Dye in an Animal Model of Descemet Membrane Endothelial Keratoplasty

PURPOSE

To evaluate the safety and feasibility of patent blue (PB) as the vital dye in Descemet membrane endothelial keratoplasty (DMEK).

METHODS

Bovine corneal endothelial cells were incubated with different concentrations (0.02%-2.5%) of PB. The cell viability, which was assessed by Cell Counting Kit-8 assay, was compared with that of untreated control and 0.06% to 0.4% trypan blue. The dyes were also used for graft preparation and implantation in the porcine eye model to evaluate stain quality, dye retention, and the feasibility of using PB in DMEK surgery.

RESULTS

No obvious increase in cytotoxicity was detected for 0.06% to 0.4% trypan blue and PB at concentrations up to 1.0%, but the cell viability after incubating with 1.5% to 2.5% PB was significantly reduced. PB at 0.5% to 1.0% generated good staining quality that can be used to facilitate graft implantation. Although the staining quality of 0.5% to 1.0% PB faded to an intermediate level after a 30-minute wash in phosphate-buffered saline, dye retention persisted for up to 24 hours.

CONCLUSIONS

PB at 0.5% to 1.0% is biocompatible and can stain the graft sufficiently, making it an alternative for DMEK surgery.

Short Axial Length and Iris Damage Are Associated With Iris Posterior Synechiae After Descemet Membrane Endothelial Keratoplasty in Asian Eyes

PURPOSE

To evaluate the frequency and severity of iris posterior synechiae after Descemet membrane endothelial keratoplasty (DMEK) and to investigate possible causes of iris posterior synechiae.

METHODS

Twenty-three eyes were investigated in 20 Asian patients who underwent DMEK 1 month after phacoemulsification and intraocular lens implantation surgery. A preexisting iris damage score was defined by iris damage and classified into 5 grades. Six months after DMEK, the iris posterior synechiae severity score was evaluated based on the extent of posterior synechiae, according to every 45 degrees of the pupillary rim (posterior synechiae score, 0-8). Correlations were analyzed between the posterior synechiae score and preexisting factors (preexisting iris damage score, axial length [AXL], anterior chamber depth, and anterior chamber volume, both before and after cataract surgery).

RESULTS

Iris posterior synechiae appeared in 20 of 23 eyes (87.0%). Best spectacle-corrected visual acuity significantly improved at 6 months after DMEK (P < 0.001). Endothelial cell density was 1596 ± 530 cells/mm (P < 0.001); loss of cell density was 37.8 ± 19.9% at 6 months. Single regression analysis showed that the onset of iris posterior synechiae was correlated with the preexisting iris damage score (P = 0.006, r = 0.55), AXL (P < 0.001, r = -0.71), anterior chamber depth (P < 0.001, r = -0.70), and anterior chamber volume before cataract surgery (P < 0.001, r = -0.79).

CONCLUSIONS

Iris posterior synechiae after DMEK frequently appeared in Asian eyes with shorter AXLs or a damaged iris.

Development of a Donor Tissue Holding Technique for Descemet's Membrane Endothelial Keratoplasty Using a 25-Gauge Graft Manipulator

Purpose

To report a modified surgical technique called the “donor tissue holding technique for Descemet's membrane endothelial keratoplasty (DMEK)” using a newly developed 25-gauge graft manipulator.

Methods

Six consecutive patients exhibiting endothelial dysfunction were enrolled and treated by DMEK. In brief, after insertion of a DMEK donor into the anterior chamber, the edge of the roll was grasped using a graft manipulator and this grasp was maintained throughout the centering and opening of the roll (holding technique). The following parameters were evaluated in comparison to the previous 10 consecutive DMEK cases in which the no touch technique was used: time of graft unfolding, incidence of intra-/postoperative complications, and best spectacle-corrected visual acuity (BCVA) and endothelial cell density (ECD) 6 months after the procedure.

Results

In both technique groups, neither intra- nor postoperative complications were noted in any case. No differences were observed between the two groups in postoperative BCVA (p = 0.88). Also, no differences were observed between the two groups in postoperative ECD (holding technique group: 2,108.3 cells/mm², no touch technique group: 1,491.7 cells/mm²) (p = 0.08) Most notably, the time of graft unfolding prior to filling with air was significantly reduced in the holding technique group (305.5 s) compared to that of the no touch technique group (1,310.0 s; p = 0.01).

Conclusions

This donor tissue holding technique enabled rapid and safe DMEK in a reproducible manner, even in Asian eyes with shallow anterior chambers with high vitreous pressure.

Evaluation of Anterior and Posterior Corneal Irregularity After Descemet Membrane Endothelial Keratoplasty

PURPOSE

To investigate the changes in anterior and posterior corneal irregularity after Descemet membrane endothelial keratoplasty (DMEK).

METHODS

This retrospective study included 27 eyes of 23 patients who underwent DMEK and 27 eyes of age-matched healthy controls. Corneal irregularity indexes, surface regularity of height (SR_H), and higher-order aberrations were evaluated in 4- and 6-mm diameters of the cornea, preoperatively and postoperatively, using anterior segment optical coherence tomography.

RESULTS

The best spectacle-corrected visual acuity (logarithm of the minimum angle of resolution) improved from 1.01 ± 0.54 preoperatively to 0.08 ± 0.11 at 6 months postoperatively. Anterior SR_H was significantly lower at 6 months postoperatively [from 1.86 ± 0.73 to 1.20 ± 0.34 (P < 0.01) (4-mm) and from 2.29 ± 0.62 to 1.64 ± 0.42 (P < 0.01) (6-mm)]. Posterior SR_H showed a significant decrease from 6.87 ± 4.19 to 2.18 ± 0.51 (4-mm) and from 5.21 ± 2.60 to 2.44 ± 0.38 (6-mm) at 6 months postoperatively (P < 0.001). The SR_H was positively correlated with best spectacle-corrected visual acuity (anterior 4 mm: R = 0.524; anterior 6 mm: R = 0.477; posterior 4 mm: R = 0.655; posterior 6 mm: R = 0.655, P < 0.001) and with higher-order aberrations for 4-mm and 6-mm diameters (R = 0.511 and R = 0.325, P < 0.001, respectively).

CONCLUSIONS

The SR_H reflects corneal irregularity and is correlated with the visual outcome after DMEK, which may be very helpful to corneal surgeons as an index indicating the severity before DMEK, and the quality of visual function after DMEK.

Outcomes of Descemet Membrane Endothelial Keratoplasty for Vitrectomized Eyes with Sutured Posterior Chamber Intraocular Lens

Purpose

To evaluate the clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) for vitrectomized eyes that underwent pars plana vitrectomy (PPV) and transscleral-sutured intraocular lens (IOL) implantation.

Methods

In this retrospective study, DMEK cases were reviewed from medical records and divided into two groups: the eyes after PPV and transscleral-sutured IOL implantation (vitrectomized group) and the eyes with in-the-bag IOL implantation (control group) prior to DMEK. The main outcome measures included time of graft unfolding during surgery and best spectacle-corrected visual acuity (BSCVA), central corneal thickness (CCT), and endothelial cell density (ECD) at 1, 3, and 6 months after the DMEK.

Results

Twenty-three eyes (vitrectomized group, n = 8; control group, n = 15) in 23 patients were included in this study. The unfolding time was significantly longer in the vitrectomized group than in the control group (P < 0.001). Postoperative BSCVA was worse in the vitrectomized group (0.16 ± 0.15) than in the control group (−0.06 ± 0.06; P = 0.017). The improvement in BSCVA was negatively correlated with the patients' age and frequency of previous surgeries.

Conclusions

Despite the longer graft unfolding time and limited visual recovery, DMEK should be applicable to vitrectomized eyes with transscleral-sutured IOL implantation.

Prevention and Management of Descemet Membrane Endothelial Keratoplasty Complications

PURPOSE

To describe Descemet membrane endothelial keratoplasty (DMEK) complications and strategies for their prevention and management.

METHODS

Five hundred consecutive eyes with DMEK of 393 patients were reviewed in this retrospective study for intraoperative and postoperative complications up to 2 years and for corresponding management.

RESULTS

Intraoperative challenges (difficult graft unfolding/positioning, high vitreous pressure, iris root hemorrhage, and Descemet membrane remnants) were encountered in 81 eyes (16.2%). Visually significant graft detachment was the main postoperative complication (34 eyes, 6.8%). Graft failure occurred in 8 eyes (1.6%). Other postoperative complications were an increase of intraocular pressure/decompensated glaucoma in 48 eyes (9.6%), significant cataract in 11 of 124 phakic eyes (8.9%), allograft rejection in 7 eyes (1.4%), cystoid macular edema in 5 eyes (1.0%), microbial keratitis in 2 eyes (0.4%), and retinal detachment in 1 eye (0.2%). Different strategies for prevention and management of these complications have been identified.

CONCLUSIONS

DMEK shows acceptable rates of complications up to 2 years after surgery, which can be managed successfully. Anticipation of potential challenges and difficulties may aid in modifying intraoperative strategies for predisposed eyes. This knowledge may further minimize complications, in particular, when performing DMEK for an extended spectrum of corneal endothelial disorders.

Trends in Corneal Transplantation from 2001 to 2016 in Germany: A Report of the DOG-Section Cornea and its Keratoplasty Registry

PURPOSE

The purpose of this retrospective panel study was to provide an overview of absolute numbers and of trends in the types of and indications for corneal transplantation in Germany from 2001 to 2016.

METHODS

A questionnaire about absolute numbers, types of transplantation, and indications was sent to 111 ophthalmologic departments in Germany, out of which 94 (85%) provided their data.

RESULTS

Since the year 2001, the number of corneal transplantations has increased by 1.5-fold, from 4730 penetrating keratoplasties (PKPs) in 2001 to 7325 penetrating and lamellar keratoplasties in 2016. The shift from penetrating to lamellar procedures began in 2006. In 2014, lamellar procedures (231 [4%] anterior and 2883 [49%] posterior lamellar keratoplasties) surpassed PKPs (2721, 47%) for the first time. Main indications for keratoplasty in Germany (2016) are Fuchs endothelial corneal dystrophy (46%), pseudophakic corneal decompensation (bullous keratopathy, 13%), repeated keratoplasty after graft failure (11%), keratoconus (8%), and corneal scarring (6%; others: 16%). The number of Descemet membrane endothelial keratoplasties (DMEKs) was 12 times higher (3850, 53%) than Descemet stripping automated endothelial keratoplasties (DSAEKs, 319, 4.4%) in 2016. The proportion of deep anterior lamellar keratoplasties (DALKs) never exceeded 6% (269 in 2011).

CONCLUSIONS

The number of keratoplasties in Germany has increased from 2001 to 2016. Since 2014, posterior lamellar keratoplasties have surpassed PKPs. There was a constant increase of DMEKs, with a 12-fold higher number compared to DSAEKs in 2016. The shorter recovery time after DMEK seems to contribute to the trend toward earlier operative intervention in corneal endothelial diseases.

Topographic characteristics after Descemet's membrane endothelial keratoplasty and Descemet's stripping automated endothelial keratoplasty

PURPOSE

To investigate the topographic characteristics of the posterior corneal surface after Descemet's endothelial membrane keratoplasty (DMEK) and Descemet's stripping automated endothelial keratoplasty (DSAEK) and their effects on postoperative visual acuity.

METHODS

Nineteen eyes of 19 patients after DMEK, 23 eyes of 23 patients after DSAEK, and 18 eyes of 18 control subjects were retrospectively analyzed. Best spectacle-corrected visual acuity (BSCVA), aberration factors (higher-order aberrations [HOAs], spherical aberrations [SAs], and coma aberrations [Comas] at 6.0 mm) were evaluated preoperatively and at 1, 3, and 6 months postoperatively. The posterior refractive pattern of the topography map was classified into 5 grades (0-5) (posterior color grade) using anterior segment optical coherence tomography. Correlations between BSCVA and some factors (abbreviation factors, posterior color grade) were analyzed.

RESULTS

BSCVA was significantly better after DMEK than after DSAEK (P < 0.001). Posterior HOAs, SAs, and Comas after each type of endothelial keratoplasty were significantly greater compared to control (P < 0.01). Posterior HOAs, total/anterior/posterior SAs, and posterior color grade were significantly lower in the DMEK group than in the DSAEK group at 3 months (P < 0.024 [posterior HOAs], P = 0.047 [total SA], P < 0.001 [anterior SAs], P = 0.021 [posterior SAs], and P < 0.001 [posterior color grade]) and 6 months postoperatively (P = 0.034 [posterior HOAs], P < 0.001 [total SAs], P < 0.001 [anterior SAs], P = 0.013 [posterior SAs], and P = 0.004 [posterior color grade]). BSCVA was significantly correlated with HOAs, SAs, and posterior color grade (P < 0.001 for all except anterior HOAs [P = 0.004]).

CONCLUSIONS

High posterior color grades were associated with larger aberration factors and had a negative effect on visual function after endothelial keratoplasty. Rapid improvement of visual function after DMEK may be attributed to less change at the posterior surface.

Use of Brilliant Blue G in Descemet's Membrane Endothelial Keratoplasty

Vital staining of the endothelial graft is essential during Descemet's membrane endothelial keratoplasty (DMEK) to ensure surgical success. DMEK surgeons worldwide commonly use trypan blue (TB) to this end. However, TB may exert toxic effects on both the cornea and retina. Recently, Brilliant Blue G (BBG) has become recognized as an alternative stain for use during vitreoretinal surgery; BBG is associated with lower levels of toxicity. We retrospectively analyzed the utility of BBG staining during DMEK. We used 0.1% (w/v) BBG to stain the DMEK grafts of 12 patients. We evaluated the best spectacle-corrected visual acuity (BSCVA), central corneal thickness (CCT), and endothelial cell density (ECD) before and 3 and 6 months after surgery. BBG was effective in terms of graft visualization during DMEK. The BSCVA (log  MAR) improved from 0.99 ± 0.57 to 0.01 ± 0.07 (p < 0.05). The CCT decreased from 720.3 ± 58.1 μm preoperatively to 511.5 ± 50.6 μm at 6 months postoperatively (p = 0.0001). The ECD decreased from 2,754 ± 296 cells/mm² to 1,708 ± 426 cells/mm² at 6 months postoperatively (p < 0.001). The ECD loss was 37.9 ± 16.3%. The outcomes using BBG were comparable to those of earlier reports that employed TB; thus, BBG may be a viable alternative to TB.